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Nighttime eating, particularly before bed, has received considerable attention. Limiting and/or avoiding food before nighttime sleep has been proposed as both a weight loss strategy and approach to improve health and body composition. Indeed, negative outcomes have been demonstrated in response to large mixed meals in populations that consume a majority of their daily food intake during the night. However, data is beginning to mount to suggest that negative outcomes may not be consistent when the food choice is small, nutrient-dense, low energy foods and/or single macronutrients rather than large mixed-meals. From this perspective, it appears that a bedtime supply of nutrients can promote positive physiological changes in healthy populations. In addition, when nighttime feeding is combined with exercise training, any adverse effects appear to be eliminated in obese populations. Lastly, in Type I diabetics and those with glycogen storage disease, eating before bed is essential for survival. Nevertheless, nighttime consumption of small (~150 kcals) single nutrients or mixed-meals does not appear to be harmful and may be beneficial for muscle protein synthesis and cardiometabolic health. Future research is warranted to elucidate potential applications of nighttime feeding alone and in combination with exercise in various populations of health and disease.
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Nutrients 2015, 7, 2648-2662; doi:10.3390/nu7042648
ISSN 2072-6643
The Health Impact of Nighttime Eating: Old and
New Perspectives
Amber W. Kinsey 1 and Michael J. Ormsbee 1,2,*
1 Institute of Sports Sciences & Medicine, Department of Nutrition, Food and Exercise Sciences,
Florida State University, Tallahassee, FL 32306, USA; E-Mail:
2 Discipline of Biokinetics, Exercise and Leisure Sciences, University of KwaZulu-Natal,
Durban 4041, South Africa
* Author to whom correspondence should be addressed; E-Mail:;
Tel.: +1-850-644-4793; Fax: +1-850-645-5000.
Received: 25 January 2015 / Accepted: 2 April 2015 / Published: 9 April 2015
Abstract: Nighttime eating, particularly before bed, has received considerable attention.
Limiting and/or avoiding food before nighttime sleep has been proposed as both a weight
loss strategy and approach to improve health and body composition. Indeed, negative
outcomes have been demonstrated in response to large mixed meals in populations that
consume a majority of their daily food intake during the night. However, data is beginning
to mount to suggest that negative outcomes may not be consistent when the food choice is
small, nutrient-dense, low energy foods and/or single macronutrients rather than large
mixed-meals. From this perspective, it appears that a bedtime supply of nutrients can
promote positive physiological changes in healthy populations. In addition, when nighttime
feeding is combined with exercise training, any adverse effects appear to be eliminated in
obese populations. Lastly, in Type I diabetics and those with glycogen storage disease, eating
before bed is essential for survival. Nevertheless, nighttime consumption of small (~150 kcals)
single nutrients or mixed-meals does not appear to be harmful and may be beneficial for
muscle protein synthesis and cardiometabolic health. Future research is warranted to
elucidate potential applications of nighttime feeding alone and in combination with exercise
in various populations of health and disease.
Keywords: nighttime eating; health; metabolism
Nutrients 2015, 7 2649
1. Introduction
Nighttime eating, particularly before bed, is a topic that has received considerable media attention in
recent years. Over the past decades it was thought that health and weight conscious individuals should
limit and/or avoid food in the hours close to nighttime sleep because it would negatively impact health
and body composition. Ultimately, this may increase the risks for cardiometabolic diseases such as
obesity and diabetes. However, recent studies investigating the impact of pre-sleep nutrient intake have
reported positive physiological outcomes in various populations. This review will examine the factors
that have contributed to previous opinions on the health impact of nighttime eating and explore new
evidence suggesting that our understanding of nighttime eating may need to be modified based on the
content and quantity of the food consumed during this time.
2. Effect of Nighttime Eating: An Old Perspective
The arguments in favor of limiting and/or avoiding food intake late in the night are supported by data
demonstrating diurnal variations in glucose tolerance [1], gastric emptying [2], resting energy
expenditure [3]. Moreover, in healthy normal weight men, it has been demonstrated that the postprandial
metabolic response to identical meals changes throughout the day [4,5]. For instance, when identical
meals (~544 kcals; 15% protein, 35% fat, 50% carbohydrate) are consumed either in the morning,
afternoon, or night, the thermic response to that meal appears to be the lowest with nighttime intake [4].
Similarly, studies in free-living healthy adults have shown that meal satiety also varies with time of day
and that food intake during the night is less satiating and leads to greater daily caloric intake compared
to food consumed in the morning hours [6,7]. Collectively, these studies demonstrate that the fate of
ingested nutrients changes throughout the day and that nighttime intake, when compared to daytime
intake, may lead to over-eating and weight gain with potential metabolic consequences. In light of this,
it has been suggested that food consumed at night, prior to sleep, may have adverse effects on health.
While data from animal studies appear to support this concept [8,9], not all studies concur [10]. In
human trials, populations of shift workers [11], those with the Night Eating Syndrome (NES; consume
a large percentage of total daily calories after dinner) [12], and epidemiological data [13–17] suggest
that consuming a majority of daily nutrients in the evening may have adverse health consequences (see
the following references for thorough reviews on shiftwork [11,18] and NES [19])). Briefly, regarding
shiftwork (characterized by irregular work hours to provide service throughout a 24 h day), available data
suggest that shiftwork, but more so night shiftwork, is a risk factor for negative health outcomes [11,18].
For example, it has been shown that night shift workers tend to have a higher prevalence of
overweightness, abdominal obesity [20], elevated triglycerides, dyslipidemia, impaired glucose
tolerance [21–25], and decreased kidney function [26] compared to day workers. In a study of simulated
night shiftwork in normal weight women, reductions in both total daily energy expenditure and the
thermic effect of dinner were highlighted as contributing mechanisms for weight gain, obesity and
impaired health as a result of shiftwork [27]. Thus, these data demonstrate an increased cardiometabolic
risk with night shiftwork.
Similarly, NES is associated with obesity in some studies [16,28,29]. It is unclear, however, as to
whether obesity is a consequence or cause of NES. Compared to those who do not eat late at night,
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individuals with NES consume a larger portion of their total calories at night (≥50% after dinner) and
have higher overall daily and evening caloric intake in some [30,31], but not all cases [32–34]. Likewise,
those with NES have higher 24 h respiratory quotient indicative of greater carbohydrate oxidation and
less fat oxidation [35] compared to those without NES. In addition, those with NES consume double the
amount of carbohydrate and protein and four times the fat [32] in daily meals compared to those without
NES. It is practical to assume that these behaviors would predispose night eaters to weight gain,
particularly if food is consumed in chronic excess [36]. However, not all studies report differences in
daily caloric intake between night eaters and controls [3234] and, it is interesting to note that NES is also
present in normal-weight/non-obese individuals [12,30,31,37,38]. The possibility of the non-obese night
eaters engaging in compensatory weight maintenance behaviors (e.g., exercise) cannot be ignored [31] as
this would be a plausible explanation for any weight-related differences observed. It is also possible that
NES may be a precursor to obesity as one study found that the only difference in NES characteristics
between obese and non-obese adults was that the non-obese night eaters were significantly younger [37]
suggesting that in the long-term, NES may lead to obesity. Others have found that night eating impairs
weight loss attempts [39] and is only associated with weight gain in already-obese individuals [13].
These data from shift workers and NES populations provide some evidence to suggest that consuming
the majority of daily nutrients late in the evening may have health consequences. However, this concept
cannot be fully understood without considering, the influence of sleep, or lack thereof. An inverse
relationship exists between sleep duration and body mass index with a greater likelihood of obesity in
those reporting less than 7–9 h of sleep each night [40]. Indeed, both shift workers [41] and individuals
with NES [30] report higher levels of subjective sleep disturbances (short sleep, reduced sleep quality,
difficulty falling asleep) compared to their respective counterparts. Sleep duration plays a significant
role in human behavior [42] and, while speculative, when the duration of sleep is short it is likely that
there are just more opportunities (awake hours) to eat and, in the long term, promote unfavorable body
composition changes.
Indeed, some epidemiological data suggests that consuming a higher proportion of calories later in
the day, as opposed to earlier in the day, is associated weight gain [13–17]. However, not all studies
agree [12,36,38,43]. It is important to note that several inconsistencies exist in the research examining
the effect of late evening caloric intake and body weight. Some of these discrepancies include, but are
not limited to: (1) differences in the calories consumed within a specified time frame (i.e., intake after
5 pm [44] vs. 8 pm [14], (2) whether it constitutes a portion of the dinner meal [12] or solely post-dinner
intake, and (3) whether the individual wakes up from sleep to eat [12]. Despite these inconsistencies it
is evident that consuming large quantities of food (binge eating) in the late evening may have adverse
health implications.
3. Effect of Nighttime Eating: A New Perspective
As demonstrated above, consuming large meals or the majority of daily nutrients late in the evening
may increase susceptibility to obesity and other cardiometabolic diseases. While this may hold true when
large quantities of food intake occurs at night, data is beginning to mount to suggest that this finding is not
consistent if the food choice is altered to favor small, nutrient-dense, low energy foods and/or single
macronutrients (<200 kcals) [4550]. In fact, recent studies have examined the impact of low-energy
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nutrient intake that occurs in close proximity to sleep and reported positive findings [4550]. Conversely,
one study [51] compared the impact of a 200 calorie snack (carbohydrate, 20.6 ± 2.6 g; protein,
2.6 ± 1.1 g; fat 11.0 ± 1.0 g) consumed in the daytime (1000 h) or nighttime (2300 h) for 13 days in
healthy, normal weight women (n = 11, age, 23 ± 1 years, BMI 20.6 ± 2.6 kg/m2). It was reported that
despite no difference in nutrient composition or calorie intake for each 13 day period, the nighttime
eating resulted in small decreases in 24 h fat oxidation and small increases in total cholesterol [51]. The
short duration of this study does not allow for conclusions to be drawn with regard to body composition
changes, however, body weight was unchanged. Nevertheless, as there is typically a long duration
between eating dinner, sleep, and the next main meal (i.e., breakfast the following morning), the
overnight period may represent a 6–8 h window of opportunity to potentially optimize health,
metabolism and overall human performance. Fortunately, short-term preliminary studies have provided
insight to the potential benefits of pre-sleep nutrient intake and its relevance to healthy, active
young [47,52] and older individuals [45] and diseased populations [46,48–50,53,54] (Table 1).
3.1. Young, Active Individuals
It is well known that acute improvements in muscle protein synthesis, glycogen resynthesis, anabolic
hormones, and performance outcomes are optimized when nutrients are consumed in close proximity to
exercise (i.e., before, during, or immediately after exercise) [55–58] rather than delaying intake for hours
before and after exercise [59,60]. Of interest, but lacking scientific support, is whether the consumption
of nutrients prior to sleep has the potential to augment physiological adaptations and outcomes, perhaps
when combined with traditional nutrient timing strategies. The benefits of a nocturnal supply of nutrients
during the overnight period may have a pivotal role in sport and performance nutrition as active
individuals, athletes, and fitness enthusiasts alike are constantly looking for ways to maximize
physiological adaptations, achieve optimal body composition, and improve performance.
Protein intake prior to sleep is commonplace among active individuals but until now, evidence-based
outcomes from this practice were nonexistent [47,52]. Res et al. [52] was the first to investigate whether
casein protein consumed before sleep could improve post-exercise recovery. Following a full day of
dietary standardization, sixteen recreationally active males performed a single 45 min bout of resistance
type exercise in the evening (2000 h). Immediately following exercise all participants were given
identical post-exercise beverages (60 g carbohydrate, 20 g whey protein). Approximately 30 min before
sleep (~2.5 h post-exercise) participants received either 40 g of casein protein (160 kcals; intrinsically
L-[1-13C]phenylalanine-labeled casein obtained from Holstein cow infusion) or a non-caloric placebo
beverage. Compared to the placebo group, those receiving the casein before sleep had higher plasma
essential amino acid concentrations indicating that protein ingestion before sleep was effectively
digested and absorbed. The increase in amino acid availability translated to higher whole-body and
muscle protein synthesis rates (~22%, Figure 1A) and a net positive protein balance during the overnight
period in the group receiving protein compared to the placebo control [52].
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Table 1. Effects of small meals/snack consumed at night.
Waller et al. [46] Consume cereal with 2/3 cup of fat-free milk at
least 90 min post-dinner vs. or no-cereal for
4 weeks
Overweight and
obese adults Cereal (100135 kcals) with low
fat milk (~60 kcals)
↓ Body weight
(0.84 ± 1.61 kg)
Groen et al. [45] Single dose of CAS during sleep via nasogastric
tube Elderly men 40g CAS (160 kcals)
↑ Muscle protein synthesis
↓ Hunger (the following
Res et al. [52] Acute resistance exercise bout (20002100 h)
followed by single dose of CAS 2.5 h post exercise
(2330 h) and then sleep (2400 h)
active men 40g CAS (160 kcals) ↑ Muscle protein synthesis
Hibi et al. [51] Consume a snack during the day (1000 h) or night
(2300 h) for 13 days
Normal weight
200 kcal snack
(20g CHO, 3 g protein, 11g fat)
↓24 h fat oxidation
↑ Total & LDL cholesterol
Madzima et al. [47] Single dose of WH, CAS, CHO or Placebo
consumed 30 min before bed Physically active
CHO (33 g, 150 kcals)
WH (30 g, 150 kcals)
CAS (30 g,140 kcals)
Placebo (0 kcals)
↑ Morning metabolism with
Kinsey et al. [48] Single dose of WH, CAS, CHO consumed 30 min
before bed Overweight and
obese women
CHO (33 g, 150 kcals)
WH (30 g, 150 kcals)
CAS (30 g,140 kcals)
↑ Morning insulin in all
↓ Hunger (the following
Figueroa et al. [50] Single dose of WH, CAS, CHO consumed 30 min
before bed and exercise
training for 4 weeks
Obese women CHO (33 g, 150 kcals)
WH (30 g, 150 kcals)
CAS (30 g,140 kcals)
↓ Blood pressure
↓ Arterial stiffness
Ormsbee et al. [49] Single dose of WH, CAS, CHO consumed 30 min
before bed and exercise
training for 4 weeks
Overweight and
obese women
CHO (33 g, 150 kcals)
WH (30 g, 150 kcals)
CAS (30 g,140 kcals)
↑ Morning satiety with CAS
Greater magnitude of ↓ body
fat and fat mass with WH
Notes: WH, whey protein; CAS, casein protein; CHO, carbohydrate; ↑ , increase; ↓ decrease; all studies were randomized, controlled, trials.
Nutrients 2015, 7 2653
Casein protein has been suggested to be best before sleep as it is a slow-release protein [61] and may
prolong the anabolic milieu, however, the lack of available data comparing the effect of different
macronutrients and proteins consumed before sleep limits the ability to draw specific conclusions.
Recent work from Madzima et al. [47] were the first to compare different macronutrients (carbohydrate
vs. protein) and proteins (casein vs. whey) to a non-caloric placebo consumed prior to sleep on
next-morning satiety and metabolism, independent of an exercise stimulus, in healthy, physically active
young men. This study had a randomized, double blind, crossover design with treatments separated by
48–72 h. Supplements were provided in beverage form at ingested at least two hours after dinner but
within 30 min of going to bed. The authors reported no differences between casein (140 kcal; 30 g
micellar casein, 3 g carbohydrate, 0.5 g fat), whey (150 kcal; 30 g whey protein with a 50% blend of
whey protein isolate and concentrate, 4 g carbohydrate and 1.5 g fat), or carbohydrate (150 kcal; 0 g
protein, 34 g maltodextrin and 2 g fat) in satiety or metabolism. Interestingly, it was reported that
consuming a caloric beverage prior to sleep, regardless of type, increased resting energy expenditure,
measured the following morning, compared to a non-caloric beverage (Figure 2) [47].
The role of pre-sleep nutrition in active individuals is a largely unexplored area and available data are
limited. However, taken together, the data suggest that it may be advantageous for active individuals to
consume a small, nutrient dense, high protein beverage (~150 kcals) before bed [47,52]. It is plausible
to hypothesize that acute enhancements in overnight muscle protein synthesis and next morning resting
metabolism may further aid in the maintenance of and/or improvement in body composition and thereby
provide a competitive advantage in healthy, physically active individuals. While this is exciting, data
does not exist to support or refute these ideas. However, it is clear that longer-term studies are warranted
to see if meaningful differences exist over time in terms of exercise adaptations and performance or
recovery outcomes (i.e., strength or time trial performance, glycogen resynthesis, muscle damage, and
inflammation). Furthermore, when training or competition occurs late in the evening (e.g., many
recreational sports and clubs) or early in the morning following an overnight fast (e.g., endurance
events), the potential benefits of pre-sleep nutrition are evident.
Figure 1. Overnight Mixed Muscle Protein Synthesis in Younger (A) and Older Men (B).
PLA, placebo; PRO, protein. This figure was adapted and redrawn from Res et al. [52] and
Groen et al. [45]. These studies determined mixed muscle protein fractional synthetic rate
using L-[ring-2H5]phenylalanine enrichment as a precursor. * indicates significant difference
from PLA.
Nutrients 2015, 7 2654
Figure 2. Resting Energy Expenditure Following Nighttime Macronutrient Ingestion in
Young Active Men. PLA, placebo; CHO, carbohydrate; WH, whey protein; CAS, casein
protein. This figure was adapted and redrawn from Madzima et al. [47]. * indicates
significant difference from CHO, WH, and CAS.
3.2. Older Individuals
In today’s society people are living longer and the older population continues to grow at an alarming
rate. In addition, older individuals have an increased risk of developing sarcopenia, the progressive loss
of muscle mass and strength that increases the risk for physical disability, poor quality of life and reduced
physical performance [62]. As aging and life expectancy are on the rise, multifactorial strategies aimed
at attenuating sarcopenia to maintain functionality and quality of life are essential. Providing nutrients
in close proximity to or during sleep to maintain and/or attenuate the loss of muscle mass may be a novel
nutrition concept worthy of exploration.
To date, there is only one study that examined whether protein provided during sleep is properly
digested and absorbed, and can subsequently improve overnight muscle protein synthesis in sixteen
elderly men [45]. Due to the presence of a circadian variation in gastric emptying [2], it was speculated
that providing nutrients at this time may not be efficiently utilized. Groen et al. administered 40 g of
casein protein (intrinsically L-[1-13C]phenylalanine-labeled casein) through a nasogastric tube during
sleep (0200–0205 h) and simultaneously assessed dietary protein digestion and absorption kinetics and
muscle protein synthesis during overnight sleep in vivo. Consistent with findings in recreationally active
men [52], this study reported that protein administration during sleep was well digested and absorbed
and concomitantly promoted overnight muscle protein accretion in elderly men (Figure 1B) [45]. This
find is interesting and highlights the potential significance of pre-sleep protein intake in populations
susceptible to muscle loss and wasting (e.g., aging, cancer cachexia).
3.3. Obesity and Other Diseases
3.3.1. Obesity
Given the growing interest in nighttime eating and its potential link to obesity and other
cardiometabolic diseases, it is important to examine the impact of nighttime macronutrient choices on
health outcomes in these populations. Waller et al. [46] demonstrated that providing a low fat, low
calorie nighttime snack as opposed to the typical high fat/high calorie food option may be beneficial to
Nutrients 2015, 7 2655
overweight and obese adults. In this four week study, overweight and obese adults (n = 58; age,
18–65 years) were randomized to receive a structured, post-dinner snack consisting of cereal (1 cup of
ready-to-eat cereal containing 100135 kcals, 23–32 g carbohydrates, 26 g protein, <0.5g fat, and
1–1.5 g fiber) and 2/3 cup of low-fat milk (~60 kcals) or a control group that maintained their normal eating
and post-dinner snacking behaviors (average snacking = 6.19 ±1.58 evenings per week, mean ± SD).
The cereal was consumed every night at least 90 min after dinner for the duration of the study and the
control group was offered the cereal after the initial four weeks. Findings from this study indicated that
having a structured, post-dinner snack resulted in lower total daily caloric intake, evening caloric intake
and modest weight loss (0.84 ± 1.61 kg) in compliant individuals [46]. While not explicitly described,
an interesting theory is that less food was consumed at dinner when it was known that an evening snack
would be available.
In an acute study, Kinsey et al. [48] investigated the effect of different macronutrients (carbohydrate
vs. protein) and proteins (casein vs. whey) consumed at night before sleep on next morning appetite and
cardiometabolic risk in sedentary overweight and obese women. The single-macronutrient beverages
(casein vs. whey vs. carbohydrate; 140–150 kcals) and supplementation protocol (two hours post-dinner
but within 30 min of sleep) in this study were identical to those used by Madzima et al. [47]. This study
revealed that these nighttime macronutrient beverages, regardless of type, lead to greater subjective
satiety and less desire to eat. However, regardless of consumption of protein-only or carbohydrate-only,
a small but significant increases in insulin levels and subsequent insulin resistance, as calculated using
the homeostatic model of insulin resistance, was observed the morning following nighttime feeding [48].
The latter finding suggests that nighttime ingestion of protein or carbohydrate before sleep may elicit
unfavorable metabolic effects in sedentary overweight and obese women. However, it was speculated
that longer-duration interventions that combine pre-sleep nutrient intake with daily exercise may
ameliorate this effect.
Interestingly, two recent studies [49,50] were designed to test the additive effect of four weeks of
exercise training (3×/week; 2 days of resistance training and 1 day of high intensity cardiovascular
interval training) and nighttime macronutrient ingestion (every night; beverages identical to those used
by Madzima et al. [47] and Kinsey et al. [48]) on various health and performance outcomes.
Ormsbee et al. [49] examined the additive effects of nighttime consumption of whey, casein or a
carbohydrate beverage on appetite, cardiometabolic health and muscular strength in overweight and
obese women (body mass index range: 25.7–47.5 kg/m2). As a result of exercise training, all groups
showed modest, albeit significant, increases in muscle strength and lean mass, and decreased body fat
(as measured by dual energy X-ray absorptiometry). Regarding appetite changes, greater morning satiety
was reported in the group consuming casein at night compared to those consuming whey or
carbohydrate. More importantly, the increase in morning insulin levels and insulin resistance observed
acutely by Kinsey et al. [48] in response to nighttime protein and carbohydrate intake was abolished
when exercise training was added to nighttime feeding in obese women [49]. Interestingly, although not
statistically significant, it is noteworthy to mention that both acutely [48] and after four weeks [49] the
direction of change for next morning metabolism was positive for the groups ingesting protein before
sleep and negative for those ingesting carbohydrates (Figure 3). Considering that a higher protein diet
has been shown to attenuate the typical drop in metabolism during sleep in overweight and obese adults,
as compared to diets higher in carbohydrate and fat [63], these changes may have physiological relevance.
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Figure 3. Resting Metabolic Rate (percent changes) Following Acute (A) and Four Weeks
(B) of Nighttime Macronutrient Ingestion in Overweight and Obese Women. CHO,
carbohydrate; WH, whey protein; CAS, casein protein. This figure was adapted and redrawn
from Kinsey et al. [48] and Ormsbee et al. [49].
Moreover, Figueroa et al. [50] examined the impact of nighttime ingestion of whey or casein protein
on blood pressure, and arterial function in young obese women with high blood pressure compared to a
carbohydrate control group. This study demonstrated that the combination of nighttime protein
supplementation and exercise training reduced both aortic systolic blood pressure, arterial stiffness (as
measured by pulse wave velocity), and augmentation index compared to baseline and the
carbohydrate beverage.
Overall, it appears that when exercise is combined with nighttime feeding of small, protein-rich
nutrient intake before sleep, some positive physiological adaptations may occur in obese women.
The benefit for other clinical populations, however, deserves some consideration.
3.3.2. Glycogen Storage Disease and Diabetes
Patients with certain glycogen storage diseases (GSD) and those with Type 1 Diabetes (T1DM) are
susceptible to nocturnal hypoglycemia and bedtime nutrient delivery provides an avenue for a supply of
glucose during the night. GSDs are a group of genetic disorders that result from defects in enzymes
required for glycogen synthesis or degradation [64]. Type I GSD is characterized by a deficiency in
glucose-6 phosphatase activity, the liver enzyme required to dephosphorylate glucose to help maintain
blood glucose levels. During the overnight period (i.e., an extended fasting period) the liver is primarily
responsible for maintaining blood glucose levels, however, the metabolic defect associated with Type 1
GSD impairs glycemic regulation. Accordingly, treatments for this condition are aimed at dietary
regimens that provide a constant supply of glucose throughout the day and night to prevent
hypoglycemia [64]. Studies have shown that individuals with Type I GSD can benefit from nighttime
nutrient availability [53,65,66]. Traditional practice has been to provide uncooked cornstarch, a slow digesting
Nutrients 2015, 7 2657
carbohydrate and an effective source of continuous glucose for the prevention of hypoglycemia [67],
at various intervals (2–5 h) throughout the day with nightly doses being administered by nasogastric
feeding [66] or by interrupting sleep and waking the individual to eat [53]. The latter option is not ideal
but, unfortunately, is most applicable and cost-effective in free-living adults with this condition. Thus,
the efficacy of a pre-sleep option capable of sustaining blood glucose levels during sleep and hence
prevent nocturnal hypoglycemia is immense. Wolfsdorf et al. [53] compared the effects of providing
isoenergetic amounts of uncooked cornstarch orally on consecutive nights as single dose at bedtime or
as two equally divided doses given at bedtime and mid-sleep in young adults with Type 1 GSD.
The results demonstrated that blood glucose concentrations were maintained for 7 h and 9 h with the
single and divided dose respectively. This highlights the feasibility of a bedtime dose of nutrients to aid
in the maintenance of blood glucose concentrations during sleep in patients with Type 1 GSD.
T1DM is characterized by a defect in insulin production as a result of pancreatic beta cell destruction
and, as a result, these individuals must rely on exogenous insulin in order to maintain appropriate blood
glucose levels. Similar to those with Type 1 GSD, nocturnal hypoglycemia is also a concern for T1DM
patients, particularly when bedtime glucose concentrations are ≤180 mg/dL (≤10 mmol/L) [54].
Likewise, bedtime feedings of cornstarch and/or protein have been useful in reducing hypoglycemic
occurrences in populations with T1DM [54,68–70]. Kalergis et al. [54] examined the effect of bedtime
ingestion of a standard snack (191 kcals, two starch and one protein exchange according the Academy
of Nutrition and Dietetics), cornstarch snack (187 kcals), protein-rich snack (192 kcals), and no snack
(0 kcals, aspartame-containing drink) on nocturnal hypoglycemia in patients with T1DM undergoing
intensive insulin management. In this study, both the standard and protein-rich snacks were most
successful at preventing nocturnal hypoglycemia while the no snack treatment had the greatest
hypoglycemic episodes. However, although not significant, the incidence of next morning
hyperglycemia in response to these nighttime snacks was greatest for the protein snack (33%), followed
by the standard (29%) and cornstarch snack (29%), with the no snack treatment being the lowest (8%).
It can be speculated that increased glucagon secretion and decreased insulin levels in the morning may
have contributed the glycemia in this population [70]. Overall, this indicates that proper snack
composition and individual variability may need to be considered when determining appropriate bedtime
snacks for some clinical populations.
4. Conclusions
Old perspectives for nighttime eating have been primarily based on populations of shift workers, night
eating syndrome patients, and epidemiological data and suggest that the consumption of large mixed
meals combined with irregular sleep patterns increase susceptibility to weight gain, obesity, and
cardiometabolic diseases. In recent years, data from healthy men has shown that consuming small
~150 kcal protein-rich beverages appears to improve overnight muscle protein synthesis, morning
metabolism and satiety. However, the impact in healthy women has not been studied yet. In obese
women, eating before sleep has been shown to improve morning appetite but also increase insulin
resistance. However, the addition of exercise training for four weeks appears to eliminate any adverse
effects of nighttime feeding in this population and has been shown to improve some indicators of
cardiovascular health. In other diseased populations (e.g., GSD, T1DM), eating before bed is actually
Nutrients 2015, 7 2658
required for survival. However, management with individually tailored nighttime feeding protocols may
optimize their clinical outcomes. Clearly, more research is required to examine this new perspective of
nighttime feeding (small, nutrient dense, snacks before sleep) as it relates to sedentary individuals,
athletes, and clinical populations. Moreover, identifying the role of nighttime feeding in recovery from
exercise and improving performance, if any exist, are warranted along with identifying the overnight
metabolic changes that may occur from nighttime feeding (i.e., fat metabolism).
The authors would like to thank the Florida State University Libraries Open Access Publishing Fund
for covering the publication fees for this manuscript.
Author Contributions
A.W.K. and M.J.O. conceived, designed and drafted the manuscript. All authors read and approved
the final manuscript.
Conflicts of Interest
The authors declare no conflict of interest.
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... In 16 healthy individuals (8 females (22.2 ± 2.6 yrs) and 8 males (22.8 ± 3.5 yrs)), exposure to bright light (>500 lux) in the evening and while asleep significantly increased plasma glucose and insulin levels compared to dim light exposure (<5 lux), implicating glucose intolerance and insulin insensitivity [97]. For night shift workers and individuals with night eating syndrome, a large portion of total energy intake occurs after dinner, which may contribute to health consequences [98]. Preference for certain types of food and dietary intake among shift workers has been examined in simulated and free-living conditions. ...
... Additionally, the general view of restricting food intake before sleep has been challenged due to new perspectives on food intake at night. One study has reported that small amounts of protein-rich beverages demonstrated a positive impact on muscle protein synthesis at nighttime in healthy men [98]; thus, food intake at night may contribute positively to metabolism depending on the amount and composition of the food consumed. Understanding the effect of the food composition and the amount consumed may provide ways to minimize metabolic consequences when food consumption is inevitable at nighttime. ...
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Light is an essential part of many life forms. The natural light–dark cycle has been the dominant stimulus for circadian rhythms throughout human evolution. Artificial light has restructured human activity and provided opportunities to extend the day without reliance on natural day–night cycles. The increase in light exposure at unwanted times or a reduced dynamic range of light between the daytime and nighttime has introduced negative consequences for human health. Light exposure is closely linked to sleep–wake regulation, activity and eating patterns, body temperature, and energy metabolism. Disruptions to these areas due to light are linked to metabolic abnormalities such as an increased risk of obesity and diabetes. Research has revealed that various properties of light influence metabolism. This review will highlight the complex role of light in human physiology, with a specific emphasis on metabolic regulation from the perspective of four main properties of light (intensity, duration, timing of exposure, and wavelength). We also discuss the potential influence of the key circadian hormone melatonin on sleep and metabolic physiology. We explore the relationship between light and metabolism through circadian physiology in various populations to understand the optimal use of light to mitigate short and long-term health consequences.
... Previous studies have mainly focused on the effect of nighttime snacking on the physiological functions of older adults. Results showed that eating a small amount of nutrient-dense but low-energy food before sleep could promote older adults' physical health [7,9,10]. More specifically, studies have suggested that appropriate nighttime snacking compensates for anabolic resistance and benefits protein synthesis and cardiometabolic health [10][11][12][13]. ...
... The amount of energy intake is a crucial factor. Previous studies have demonstrated that a small amount (~150 kcal) of a single nutrient or mixed diet before sleep is not harmful but advantageous to physical and mental health [9]. In addition, a 4-week intervention study on sedentary obese female showed that ingesting~150 kcal of whey, casein, or carbohydrates before sleep (at least 2 h after dinner) combined with physical exercise not only reduced body fat, optimized body structure, and strength but also improved the emotional status in intervention groups [41]. ...
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Evidence shows that supplementary snacking could provide older adults with nutrients that cannot be obtained through three meals a day. However, whether and how supplementary snacking, especially nighttime snacking, affects older adults’ cognitive function remain unclear. The present study examined the effect of nighttime snacking on cognitive function for older adults. In study 1, we investigated the association between nighttime snacking and cognitive function based on data from 2618 community-dwelling older adults from the China health and nutrition survey (CHNS). In study 2, we conducted an experiment (n = 50) to explore how nighttime acute energy intake influences older adults’ performance on cognitive tasks (immediate recall, short-term delayed recall, and long-term delayed recall). Both the observational and experimental studies suggested that nighttime snacking facilitated older adults’ cognitive abilities, such as memory and mathematical ability, as indicated by subjective measures (study 1) and objective measures (studies 1 and 2). Moreover, this beneficial effect was moderated by cognitive load. These findings bridge the gap in the literature on the relationships between older adults’ nighttime snacking and cognitive function, providing insight into how to improve older adults’ dietary behaviors and cognitive function.
... Furthermore, eating fewer meals may be associated with eating out and at late hours, which can be characterized by energyrich foods with low nutrient density such as fried foods, alcohol consumption and lower amounts of foods with high nutrient density such as fruits and vegetables (Misan et al., 2019;Aljuraiban et al., 2014). Therefore, positive results have been observed when foods eaten late are small in amount, rich in nutrients and low in energy and/or macronutrients (Kinsey & Ormsbee, 2015). In addition, changes in meal frequency and timing have the potential to influence energy and macronutrient intake (Englund-Ögge et al., 2017;Paoli et al., 2019). ...
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Eating an early first meal and a tendency towards morningness have been associated with healthy eating habits. The objective of the study was to investigate the association between mealtimes of first and last meals and food consumption of pregnant women. Methods: A cross-sectional study with 111 pregnant women who use a public health service. Sociodemographic, nutritional and health data were collected from medical records. Food consumption was assessed by habitual dietary intake. Nutritional value was determined with the DietPro® program (version 6.1) and diet quality was assessed through Diet Quality Index Adapted for Brazilian Pregnant Women (IQDAG).. The study was approved by the Research Ethics Committee of Universidade Federal de Viçosa (No. 4.098.560). Results: The mean age was 34.3 (±5.5) years. Pregnant women who had a late first meal and an early last meal (PR:2.55; 95% CI 1.41-4.63) presented a higher prevalence of vitamin B12 deficiency. On the other hand, pregnant women who had a late first meal and an early last meal (PR:4.74; 95%CI 1.50-15.04), and those who had late first and last meals (PR:4.31; 95%CI 1.37; 13.58), presented a higher prevalence of having an inadequate number of meals. Conclusion: Pregnant women who eat late have a higher prevalence of vitamin B12 deficiency and eating ≤3 meals during the day compared to those who eat early. The result reinforces the need for approaches to prenatal care based on mealtimes and nutrition aimed at improving the dietary profile of this population.
... Additionally, it has been reported that late eating, which refers to delay in the timing of meals (commonly the main meal of the day or the dinner) may increase the risk for developing cardiometabolic diseases [279]. In fact, late eating was associated with abdominal obesity, inflammatory RCT randomized controlled trial, NS no significant, T2DM type 2 diabetes mellitus, NAFLD non-alcoholic fatty liver disease, PCOS polycystic ovary syndrome, MDA malondialdehyde, NF-kB transcription nuclear factor kappa B, CRP C-reactive protein, IL-6 interleukin 6, TNF-α tumor necrosis factor alpha, IL-8 interleukin 8, IL-4 interleukin 4, IL-10 interleukin 10, SIRT1 sirtuin 1, ESR erythrocyte sedimentation rate, oxLDL oxidized LDL, LDH lactate dehydrogenase biomarkers such as IL-6 and CRP, and circadian-related disturbances in children [280]. ...
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Purpose of Review Chronic low-grade inflammation may contribute to the onset and progression of communicable and chronic diseases. This review examined the effects and eventual mediation roles of different nutritional factors on inflammation. Recent Findings Potential nutritional compounds influencing inflammation processes include macro and micronutrients, bioactive molecules (polyphenols), specific food components, and culinary ingredients as well as standardized dietary patterns, eating habits, and chrononutrition features. Therefore, research in this field is still required, taking into account critical aspects of heterogeneity including type of population, minimum and maximum intakes and adverse effects, cooking methods, physiopathological status, and times of intervention. Moreover, the integrative analysis of traditional variables (age, sex, metabolic profile, clinical history, body phenotype, habitual dietary intake, physical activity levels, and lifestyle) together with individualized issues (genetic background, epigenetic signatures, microbiota composition, gene expression profiles, and metabolomic fingerprints) may contribute to the knowledge and prescription of more personalized treatments aimed to improving the precision medical management of inflammation as well as the design of anti-inflammatory diets in chronic and communicable diseases.
... Increasing awareness of the nutritional benefits of almonds may result in higher levels of almond intake and improved nutrient profile of the diet due to the contribution of almonds to the diet compared to the average snack. While nighttime snacking has a negative health connotation due to the quantity and poor quality of foods generally eaten as snacks, an evening snack can be a healthy way to improve metabolic health if small and calorie-controlled [31]. ...
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Approximately 40% of patients with type 2 diabetes (T2D) experience an early-morning rise in fasting glucose that is not effectively treated by available oral hypoglycemic agents. This study aimed to determine the acute effect of consuming almond butter as an evening snack on fasting and overnight interstitial glucose, compared to a no-snack control, in people with T2D. Adults with T2D, not taking insulin, were recruited to participate in this two-week randomized, controlled, crossover pilot study. Participants received 2 tbsp of natural almond butter as an evening snack, or a no-snack control, for one week each. Glucose was measured by continuous glucose monitor (CGM). Analyses were performed using linear mixed effect modeling in R. Ten adults (60% female; age: 57 ± 5.6 years) completed the study. The intervention did not significantly influence fasting glucose [4–6 a.m.; β = 5.5, 95% CI = [−0.9, 12.0], p = 0.091; Marginal R2 = 0.001, Conditional R2 = 0.954] or overnight glucose (12–3 a.m.; β = 5.5, 95% CI = [−0.8, 11.8], p = 0.089; Marginal R2 = 0.001, Conditional R2 = 0.958). Significant variability in continuously measured glucose was observed. These findings will inform the design of a larger investigation.
... Thus, adherence to the protocol was verified regarding similar presleep macronutrient ingestion, and its influence on baseline blood flow measured by CEUS is unknown so far. However, presleep macronutrient ingestion has been shown to alter morning metabolism and muscle protein synthesis [47,48], thereby harboring a risk of inconsistently affecting muscle perfusion [49]. ...
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Background: Various dietary supplements have been reported to enhance muscular perfusion in athletes practicing resistance training, especially through modulation of nitric oxide signaling. Objectives: The aim of this study was therefore to investigate selected 'NO-boosting' supplements in a real-life setting i) to generate novel hypotheses and perfusion estimates for power calculation in view of a definitive trial and ii) to assess the feasibility of the study design with particular focus on the use of contrast-enhanced ultrasound (CEUS) for perfusion quantification. Methods: Thirty young male athletes (24 ± 4 years) regularly practicing resistance training were enrolled in this three-arm, placebo(PL)-controlled crossover trial with ingestion of two commercially available supplements: an amino acid combination (AA) (containing 3 g of L-arginine-hydrochloride and 8 g of L-citrulline-malate) and 300 mg of a specific green tea extract (GTE). After intake, CEUS examinations of the dominant biceps brachii muscle were performed under resting conditions and following standardized resistance exercising. Quantitative parameters of biceps perfusion (peak enhancement, PE; wash-in perfusion index, WiPI) and caliber were derived from corresponding CEUS video files. Additionally, subjective muscle pump was determined after exercise. Results: For PE, WiPI, and biceps caliber, the standard deviation (SD) of the within-subject differences between PL, AA, and GTE was determined, thereby allowing future sample size calculations. No significant differences between PL, AA, and GTE were observed for biceps perfusion, caliber, or muscle pump. When comparing resting with post-exercise measurements, the increase in biceps perfusion significantly correlated with the caliber increase (PE: r = 0.266, p = 0.0113; WiPI: r = 0.269, p = 0.0105). Similarly, the biceps perfusion correlated with muscle pump in the post-exercise conditions (PE: r = 0.354, p = 0.0006; WiPI: r = 0.350, p = 0.0007). A high participant adherence was achieved, and the acquisition of good quality CEUS video files was feasible. No adverse events occurred. Conclusion: Based on our novel examination protocol, CEUS seems to be feasible following higher-load resistance exercising and may be used as a new method for high-resolution perfusion quantification to investigate the effects of pre-exercise dietary supplementation on muscle perfusion and related muscle size dynamics.
... However, strict restriction of nocturnal eating can also result in undue psychological stress and similarly lead to preterm birth [44]. As such, pregnant women might consider eating a small amount of food that is low in calories and rich in protein [45], serotonin, and folate, such as kiwifruit [46], or foods that contain melatonin, such as eggs, fish, nuts, and mushrooms [47], to address their physical needs while not compromising their sleep quality. Nevertheless, it is worth noting the potential presence of reverse causality, where poor sleep might contribute to nocturnal eating. ...
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The extent to which lifestyle practices at night influence sleep quality in pregnant women remains unknown. This study aimed to examine whether nocturnal behaviours were associated with poor sleep during pregnancy. We performed a cross-sectional analysis of a prospective cohort of pregnant women at 18–24 gestation weeks recruited from KK Women’s and Children’s Hospital, Singapore, between 2019 and 2021. Nocturnal behaviours were assessed with questionnaires, and sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) with a global score ≥5 indicative of poor sleep quality. Modified Poisson regression and linear regression were used to examine the association between nocturnal behaviour and sleep quality. Of 299 women, 117 (39.1%) experienced poor sleep. In the covariate-adjusted analysis, poor sleep was observed in women with nocturnal eating (risk ratio 1.51; 95% confidence interval [CI] 1.12, 2.04) and nocturnal artificial light exposure (1.63; 1.24, 2.13). Similarly, nocturnal eating (β 0.68; 95% CI 0.03, 1.32) and light exposure (1.99; 1.04, 2.94) were associated with higher PSQI score. Nocturnal physical activity and screen viewing before bedtime were not associated with sleep quality. In conclusion, reducing nocturnal eating and light exposure at night could potentially improve sleep in pregnancy.
... Eating before bed time has long been controversial [46,47], but for the RT population aimed at muscle gaining, they preferred ingesting protein before bedtime, which has been identified as advantageous to MPS and muscle recovery in both acute and long-term studies among both adults and older adults [48][49][50]. Antonio et al. (2017) [9] conducted an 8-week intervention in healthy males to compare the effects of consuming protein (casein, 54 g per serving) in the morning before noon versus consuming protein~90 min prior to sleep. This study found that the lean tissue mass of subjects in morning group increased by 0.4 kg, and the evening group increased by 1.2 kg despite no significant difference between groups, suggesting that supplementing casein before sleep could better stimulate MPS, which was also supported by data from Burk et al. [51]. ...
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There is increasing evidence that dietary protein intake with leucine and vitamin D is an important factor in muscle protein synthesis. This study investigated the combined effects of consuming whey protein and vitamin D3 in the evening before bedtime or in the morning after sleeping on muscle mass and strength. Healthy, untrained males (N = 42; Age = 18–24 year) were randomly assigned into three groups: before bedtime, after sleeping, and control. Subjects underwent a 6-week resistance training program in combination with supplements that provided 25 g whey protein and 4000 IU vitamin D3 for the before bedtime and after sleeping groups and a 5 g maltodextrin placebo for the control group. A significant increase in serum vitamin D was observed in both before bedtime and after sleeping groups. All groups experienced a significant gain in leg press. However, the control group did not experience significant improvements in muscle mass and associated blood hormones that were experienced by the before bedtime and after sleeping groups. No significant differences in assessed values were observed between the before bedtime and after sleeping groups. These findings suggest that the combination of whey protein and vitamin D supplements provided either before or after sleep resulted in beneficial increases in muscle mass in young males undergoing resistance training that exceeded the changes observed without these supplements.
Despite sleep's fundamental role in maintaining and improving physical and mental health, many people get less than the recommended amount of sleep or suffer from sleeping disorders. This review highlights sleep's instrumental biological functions, various sleep problems, and sleep hygiene and lifestyle interventions that can help improve sleep quality. Quality sleep allows for improved cardiovascular health, mental health, cognition, memory consolidation, immunity, reproductive health, and hormone regulation. Sleep disorders, such as insomnia, sleep apnea, and circadian-rhythm-disorders, or disrupted sleep from lifestyle choices, environmental conditions, or other medical issues can lead to significant morbidity and can contribute to or exacerbate medical and psychiatric conditions. The best treatment for long-term sleep improvement is proper sleep hygiene through behavior and sleep habit modification. Recommendations to improve sleep include achieving 7 to 9 h of sleep, maintaining a consistent sleep/wake schedule, a regular bedtime routine, engaging in regular exercise, and adopting a contemplative practice. In addition, avoiding many substances late in the day can help improve sleep. Caffeine, alcohol, heavy meals, and light exposure later in the day are associated with fragmented poor-quality sleep. These sleep hygiene practices can promote better quality and duration of sleep, with corresponding health benefits.
Nighttime eating has been associated with obesity, inflammation, and poor nutritional intake, yet correlates of this behavior are understudied in pediatric populations and among adolescents in particular. The current study examines modifiable factors related to nighttime eating, including sleep parameters and regulatory abilities—as well as the interplay between these constructs—in adolescents. A total of 223 adolescents (Mage = 15.32 years, 52.9 % female, 15.7 % classified as overweight, 21.1 % had obesity) wore ActiGraph devices to measure sleep and were instructed to complete three 24-h dietary recall measures over a two-week period. Participants also completed self-report measures of executive function. Greater variability in sleep duration was consistently associated with higher average calorie, sugar, and fat consumption after 8, 9, and 10 PM. The main effect of global executive function on all nighttime eating measures was nonsignificant, and executive function did not moderate relationships between sleep parameters and nighttime eating measures. Since adolescents' eating habits may set the stage for lifelong dietary practices, efforts to ensure consistent sleep duration may reduce risk for nighttime eating in this nutritionally vulnerable population.
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Single macronutrient intake prior to sleep reduces appetite but may negatively impact insulin sensitivity in sedentary obese women. The present study examined the additive impact of nighttime feeding of whey (WH), casein (CAS), or carbohydrate (CHO) combined with exercise training on appetite, cardiometabolic health, and strength in obese women. Thirty-seven sedentary obese women (WH, n = 13, body mass index (BMI) 34.4 ± 1.3 kg/m(2); CAS, n = 14, BMI 36.5 ± 1.8 kg/m(2); CHO, n = 10, BMI 33.1 ± 1.7 kg/m(2)) consumed WH, CAS, or CHO (140-150 kcal/serving), every night of the week, within 30 min of sleep, for 4 weeks. Supervised exercise training (2 days of resistance training and 1 day of high-intensity interval training) was completed 3 days per week. Pre- and post-testing measurements included appetite ratings, mood state, resting metabolic rate, fasting lipids, glucose, and hormonal responses (insulin, leptin, adiponectin, hs-CRP, IGF-1, and cortisol), body composition, and strength. Nighttime intake of CAS significantly (p < 0.05) increased morning satiety (pretraining, 25 ± 5; post-training 41 ± 6) more than WH (pretraining, 34 ± 5; post-training, 35 ± 6) or CHO (pre 40 ± 8, post 43 ± 7). Exercise training increased lean mass and strength, decreased body fat, and improved mood state in all groups. No other differences were noted. Nighttime feeding of CAS combined with exercise training increased morning satiety more than WH or CHO. Nighttime feeding for 4 weeks did not impact insulin sensitivity (assessed via homeostatic model assessment of insulin resistance) when combined with exercise training in obese women. NCT01830946.
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Significance Demands of modern society force many work operations into the night, when the intrinsic circadian timing system promotes sleep. Overnight shiftwork is associated with increased risk for adverse metabolic health and sleep disruption. Uncovering potential physiological mechanisms that contribute to metabolic dysregulation when work and eating occur at inappropriate circadian times is vital to the development of effective treatment strategies. In this study, healthy volunteers underwent a commonly used simulated shiftwork protocol to quantify changes in metabolic, sleep, and circadian physiology when working and eating during the night as compared with a traditional day work schedule. We demonstrate that nightshift work reduces total daily energy expenditure, representing a contributing mechanism for unwanted weight gain and obesity.
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The present study investigated whether whey (WH) protein, casein (CAS) protein or a carbohydrate placebo (PLA) consumed 30 min before sleep could acutely alter appetite or cardiometabolic risk the following morning. A total of forty-four sedentary overweight and obese women (BMI: 25·7-54·6 kg/m2) completed this stratified, randomised, double-blind, placebo-controlled study (WH: n 16, age 27·4 (sd 5·0) years; CAS: n 15, age 30·3 (sd 8·1) years; PLA: n 13, age 28·5 (sd 7·2) years). The participants came to the laboratory at baseline (visit 1) and again in the morning after night-time ingestion of either protein or PLA (visit 2). Visit 2 was conducted at least 48 h after visit 1. During visits 1 and 2, the following parameters were measured: appetite (hunger, satiety and desire to eat); resting metabolism; blood lipid and glucose levels; the levels of insulin, leptin, C-reactive protein, insulin-like growth factor-1, cortisol and adiponectin. Data were analysed using repeated-measures ANOVA. No group × time interactions were observed for the measured variables; however, a main effect of time was observed for increased satiety (P= 0·03), reduced desire to eat (P= 0·006), and increased insulin levels (P= 0·004) and homeostatic model assessment of insulin resistance values (P= 0·01) after the consumption of either protein or PLA. The results of the present study reveal that night-time consumption of protein or carbohydrate by sedentary overweight and obese women improves their appetite measures but negatively affects insulin levels. Long-term studies are needed to evaluate the effects of chronic consumption of low-energy snacks at night on body composition and cardiometabolic risk.
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Obesity and reduced muscle strength are associated with increased blood pressure (BP). We examined the impact of milk proteins and combined exercise training (CET) on BP, arterial function, and muscle strength (one-repetition maximum (1-RM)). Thirty-three obese sedentary women (age = 30±1 years; body mass index = 35.2±0.9kg/m(2); systolic BP (SBP) = 129±2mm Hg) were randomized to control carbohydrate (n = 11), whey (n = 11), and casein (n = 11) supplementation for 4 weeks. All participants performed moderate-intensity CET 3 days/week. Brachial and aortic SBP, augmentation index adjusted for 75 beats/minute (AIx@75), arterial stiffness (brachial-ankle pulse wave velocity (baPWV)), and 1-RM were measured before and after the interventions. There were significant (P < 0.05) time-by-group interactions for brachial SBP (bSBP), aortic SBP (aSBP), AIx@75, and baPWV. Whey and casein supplementation significantly (P < 0.05) decreased bSBP (approximately 5mm Hg for both), aSBP (approximately 7mm Hg and approximately 6mm Hg, respectively), AIx@75 (approximately 9.2% and approximately 8.1%, respectively) and baPWV (approximately 57cm/s and approximately 53cm/s, respectively) compared with no changes in the control group. Upper- (approximately 22.2%) and lower-body 1-RM (approximately 44.0%) increased similarly in all groups. Changes in arterial function and 1-RM were not correlated. Milk protein supplementation with CET reduced SBP, wave reflection, and arterial stiffness in young obese women with prehypertension and hypertension. Because CET did not affect arterial function, milk proteins may have an antihypertensive effect by improving arterial function, as shown by reduced AIx@75 and baPWV. Muscle strength improvements after CET did not affect BP and arterial function. Registration NCT01830946.
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Objective: To examine the form of the relationship between sleep duration and anthropometric measures and possible differences in these relationships by gender and race or ethnicity. Design and methods: Data for 13,742 participants aged ≥20 years from the National Health and Nutrition Examination Survey 2005-2010 were used. Sleep duration was categorized as ≤6 (short sleepers), 7-9, and ≥10 hours (long sleepers). Results: Short sleepers were as much as 1.7 kg/m² (SE 0.4) heavier and had 3.4 cm (SE 1.0) more girth than long sleepers. Among participants without depression or a diagnosed sleep disorder, sleep duration was significantly associated with body mass index (BMI) and waist circumference in an inverse linear association in the entire sample, men, women, whites, African Americans, and participants aged 20-39 years. No evidence for statistical interaction by gender and race or ethnicity was observed. Regression coefficients were notably stronger among adults aged 20-39 years. Compared to participants who reported sleeping 7-9 hours per night, short sleepers were more likely to be obese and have abdominal obesity. Conclusions: In this nationally representative sample of US adults, an inverse linear association most consistently characterized the association between sleep duration and BMI and waist circumference.
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The purpose of the present study was to investigate whether whey protein (WP), casein protein (CP), carbohydrate (CHO) or a non-energy-containing placebo (PLA) consumed before sleep alters morning appetite and resting energy expenditure (REE) in active men. A total of eleven men (age: 23·6 (sem 1·0) years; body fat: 16·3 (sem 2·5) %) participated in this randomised, double-blind, cross-over study. A single dose of WP (30 g), CP (30 g), CHO (33 g) or PLA was consumed 30 min before sleep, and each trial was separated by 48-72 h. The next morning (05.00-08.00 hours), measurements of satiety, hunger and desire to eat and REE were taken. After a 30 min equilibration period, REE in the supine position was measured for 60 min. An analysis of 10 min mean intervals over the final 50 min of the measurement period was conducted. Statistical analyses were conducted using repeated-measures ANOVA for metabolic variables, and a one-way ANOVA was used for measuring changes in appetite markers. Group differences were examined by Tukey's post hoc analysis. There were no significant differences in appetite measures among the groups. There was a main group effect for REE. The predicted REE was significantly greater after consumption of the WP (8151 (sem 67) kJ/d), CP (8126 (sem 67) kJ/d) and CHO (7988 (sem 67) kJ/d) than after that of the PLA (7716 (sem 67) kJ/d, P <0·0001). There were no significant differences between the WP and CP groups in any metabolic measurements. Night-time consumption of WP, CP or CHO, in the hours close to sleep, elicits favourable effects on the next-morning metabolism when compared with that of a PLA in active young men.
To identify the impact of shiftwork on individuals and their lives and to discuss the implications this has for nurses and nursing. The context of shiftwork in the early 21st century is changing rapidly, and those involved in or required to work shiftwork are now spread over many different sectors of the community. In the Australian community, 16% of workers regularly work shiftwork. Most nurses undertake shiftwork at some time in their career, and health services could not operate without a shiftworking nursing workforce. Narrative literature review. A narrative review of journal articles was conducted. Databases searched were CINAHL, EBSCO Host, JSTOR, Medline/PubMed and Google Scholar. Search terms used were 'shiftwork' and 'shift work'. Limitations included 'English language', 'published between 1980-2013' and 'human'. Reviewed for this paper were 118 studies that met the inclusion criteria. Results were categorised using thematic analysis. Themes that emerged were physical and psychosocial health, and sleep. Findings will be explored under these themes. Shiftwork research has mainly focussed on the physiological and psychosocial health and sleep effects. Absent from the literature are studies focussing on the personal experience of the shiftworker and how workers mediate the effects of shiftwork and how shiftwork fits into the rest of their lives. Therefore, it is difficult to draw conclusions about how people 'manage' their shiftwork, and further research needs to be undertaken in this area. Working shifts for nurses is a reality that comes with the profession. While there is a significant body of research on shiftwork, little of this has been specifically applied to nursing, and the implications for individual nurses needing to care for their own health have not been drawn.
To investigate associations between shiftwork and glomerular filtration rate among white/Hispanic (n = 273) and African American (n = 81) police officers. Analysis of variance/analysis of variance was utilized to compare mean values of estimated glomerular filtration rate (eGFR) across shiftwork categories. Shiftwork was significantly associated with eGFR among white/Hispanic officers only: day (88.6 ± 2.8), afternoon (90.6 ± 2.9), and night shift (83.1 ± 3.1 mL/min/1.73 m); afternoon versus night, P = 0.007. Percentage of hours worked on the night shift was inversely associated with mean levels of eGFR, trend P = 0.001. Body mass index modified the association between shiftwork and eGFR (interaction P = 0.038). Among officers with body mass index 25 kg/m or higher, those who worked the night shift had the lowest mean eGFR (afternoon vs night, P = 0.012; day vs night, P = 0.029). Night-shift work was associated with decreased kidney function among white/Hispanic officers. Longitudinal studies are warranted among all races.
J Physiol 2001 August 15: 535(1): 301–11(1) Age-associated loss of skeletal muscle mass and strength can partly be counteracted by resistance training, causing a net synthesis of muscular proteins. Protein synthesis is influenced synergistically by post-exercise amino acid supplementation, but the importance of the timing of protein intake remains unresolved. (2) The study investigated the importance of immediate (P0) or delayed (P2) intake of an oral protein supplement upon muscle hypertrophy and strength over a period of resistance training in elderly males. (3) Thirteen men (age 74 ± 1 years; body mass index (BMI), 25 ± 1 kg m- 2 (means ± SEM)) completed a 12-week resistance training program (three times per week) receiving oral protein in liquid form (10 g protein, 7 g carbohydrate, 3 g fat) immediately after (P0) or 2 h after (P2) each training session. Muscle hypertrophy was evaluated by magnetic resonance imaging (MRI) and from muscle biopsies and muscle strength was determined using dynamic and isokinetic strength measurements. Body composition was determined from dual-energy X-ray absorptiometry (DEXA) and food records were obtained over 4 days. The plasma insulin response to protein supplementation was also determined. (4) In response to training, the cross-sectional area of m. quadriceps femoris (54.6 ± 0.5–58.3 ± 0.5 cm2) and mean fiber area (4047 ± 320–5019 ± 615 μ m2) increased in the P0 group, whereas no significant increase was observed in P2. For P0 both dynamic and isokinetic strength increased, by 46 and 15%, respectively (P P