John F Trepanowski

University of Illinois at Chicago, Chicago, Illinois, United States

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Publications (21)35.92 Total impact

  • John F Trepanowski, Krista A Varady
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    ABSTRACT: Abstract The American Diabetes Association (ADA) and the National Cholesterol Education Program (NCEP) have each outlined a set of dietary recommendations aimed at improving glycemic control and blood lipids, respectively. However, traditional vegan diets (low-fat diets that proscribe animal product consumption) are also effective at improving glycemic control, and dietary portfolios (vegan diets that contain prescribed amounts of plant sterols, viscous fibers, soy protein, and nuts) are also effective at improving blood lipids. The purpose of this review was to compare the effects of traditional vegan diets and dietary portfolios with ADA and NCEP diets on body weight, blood lipids, blood pressure, and glycemic control. The main findings are that traditional vegan diets appear to improve glycemic control better than ADA diets in individuals with type 2 diabetes mellitus (T2DM), while dietary portfolios have been consistently shown to improve blood lipids better than NCEP diets in hypercholesterolemic individuals.
    Critical reviews in food science and nutrition. 06/2014;
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    ABSTRACT: Alternate day fasting (ADF; ad libitum "feed day", alternated with 25% energy intake "fast day"), is effective for weight loss and cardio-protection in obese individuals. Whether these effects occur in normal weight and overweight individuals remains unknown. This study examined the effect of ADF on body weight and coronary heart disease risk in non-obese subjects. Thirty-two subjects (BMI 20--29.9 kg/m2) were randomized to either an ADF group or a control group for 12 weeks. Body weight decreased (P < 0.001) by 5.2 +/- 0.9 kg (6.5 +/- 1.0%) in the ADF group, relative to the control group, by week 12. Fat mass was reduced (P < 0.001) by 3.6 +/- 0.7 kg, and fat free mass did not change, versus controls. Triacylglycerol concentrations decreased (20 +/- 8%, P < 0.05) and LDL particle size increased (4 +/- 1 A, P < 0.01) in the ADF group relative to controls. CRP decreased (13 +/- 17%, P < 0.05) in the ADF group relative to controls at week 12. Plasma adiponectin increased (6 +/- 10%, P < 0.01) while leptin decreased (40 +/- 7%, P < 0.05) in the ADF group versus controls by the end of the study. LDL cholesterol, HDL cholesterol, homocysteine and resistin concentrations remained unchanged after 12 weeks of treatment. These findings suggest that ADF is effective for weight loss and cardio-protection in normal weight and overweight adults, though further research implementing larger sample sizes is required before solid conclusion can be reached.
    Nutrition Journal 11/2013; 12(1):146. · 2.65 Impact Factor
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    ABSTRACT: Alternate day fasting combined with exercise is effective for weight loss. The aim of this study was to examine the behavioral adaptations that occur when ADF is combined with exercise, and to determine how these changes affect weight loss. Obese subjects (n = 64) were randomized to 1 of 4 groups: 1) combination (ADF + endurance exercise), 2) ADF, 3) exercise, or 4) control, for 12 weeks. Body weight decreased (P < 0.05) in the combination group (6 +/- 4 kg), ADF (3 +/- 1 kg), exercise group (1 +/- 0 kg), with no change in the control group (0 +/- 0 kg). When given the choice, subjects chose to exercise the same amount (P = 0.790) on the fast days (48 +/- 2%) as feed days (52 +/- 2%). Percent of exercise sessions performed on fast day mornings (20 +/- 6%) did not differ (P = 0.453) from fast day afternoons (28 +/- 5%). Likeliness to cheat on the fast day was not higher if the subject exercised in the afternoon (17 +/- 7%) versus the morning (10 +/- 5%). Hunger decreased (P < 0.05) while satisfaction and fullness increased (P < 0.05) post-treatment in the ADF group only. Restrained eating increased (P < 0.05) and uncontrolled eating decreased (P < 0.05) in the combination and ADF groups. These findings suggest that endurance exercise is an excellent adjunct therapy to ADF, as it leads to positive behavioral changes that may contribute to long-term steady weight loss.
    Journal of the International Society of Sports Nutrition 11/2013; 10(1):50. · 1.83 Impact Factor
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    ABSTRACT: Objective: This study examined whether the combination of Alternate day fasting (ADF) plus exercise produces superior changes in body composition and plasma lipid levels when compared to each intervention alone. Designs and Methods: Obese subjects (n = 64) were randomized to 1 of 4 groups for 12 weeks: 1) combination (ADF plus endurance exercise), 2) ADF, 3) exercise, or 4) control. Results: Body weight was reduced (P < 0.05) by 6 ± 4 kg, 3 ± 1 kg, and 1 ± 0 kg in the combination, ADF, and exercise group, respectively. Fat mass and waist circumference decreased (P < 0.001) while lean mass was retained in the combination group. LDL cholesterol decreased (12 ± 5%, P < 0.05) and HDL cholesterol increased (18 ± 9%, P < 0.05) in the combination group only. LDL particle size increased (P < 0.001) by 4 ± 1 Å and 5 ± 1 Å in the combination and ADF group, respectively. The proportion of small HDL particles decreased (P < 0.01) in the combination group only. Conclusions: These findings suggest that the combination produces superior changes in body weight, body composition, and lipid indicators of heart disease risk, when compared to individual treatments.
    Obesity 02/2013; · 3.92 Impact Factor
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    Richard J Bloomer, John F Trepanowski, Tyler M Farney
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    ABSTRACT: Coffee has been reported to be rich in antioxidants, with both acute and chronic consumption leading to enhanced blood antioxidant capacity. High-fat feeding is known to result in excess production of reactive oxygen and nitrogen species, promoting a condition of postprandial oxidative stress. We tested the hypothesis that coffee intake following a high-fat meal would attenuate the typical increase in blood oxidative stress during the acute postprandial period. On 3 different occasions, 16 men and women consumed a high-fat milk shake followed by either 16 ounces of caffeinated or decaffeinated coffee or bottled water. Blood samples were collected before and at 2 and 4 hours following intake of the milk shake and analyzed for triglycerides (TAG), malondialdehyde (MDA), hydrogen peroxide (H2O2), and Trolox equivalent antioxidant capacity (TEAC). Values for TAG and MDA (P < 0.001), as well as for H2O2 (P < 0.001), increased significantly following milk shake consumption, with values higher at 4 hours compared with 2 hours post consumption for TAG and H2O2 (P < 0.05). TEAC was unaffected by the milk shake consumption. Coffee had no impact on TAG, MDA, H2O2, or TEAC, with no condition or interaction effects noted for any variable (P > 0.05). Acute coffee consumption following a high-fat milk shake has no impact on postprandial oxidative stress.
    Nutrition and Metabolic Insights 01/2013; 6:35-42.
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    ABSTRACT: Objective Alternate day fasting (ADF; which consists of an ad libitum “feed day” alternated with a 75% energy restriction “fast day”) combined with exercise improves several coronary heart disease (CHD) risk factors. However, the effect of this combination therapy on endothelial function, and the role that adipokines play in mediating this effect, is unknown. Accordingly, this study examined the effect of ADF combined with exercise on brachial artery flow mediated dilation (FMD) and plasma adiponectin and leptin. Research methods and procedures Sixty-four obese subjects were randomized to 1 of 4 groups: 1) combination (ADF + endurance exercise), 2) ADF, 3) exercise, or 4) control, for 12 weeks. Results Body weight decreased (P < 0.05) in the combination (−6 ± 4 kg), ADF (−3 ± 1 kg) and exercise group (−1 ± 0 kg). Fat mass decreased (P < 0.01) in the combination (−5 ± 1 kg) and ADF (−2 ± 1 kg) groups. FMD increased (P < 0.05) only in the ADF group (5 ± 1% to 10 ± 2%; 5% increase). Leptin decreased in the combination (−34 ± 9 ng/ml, P < 0.001), ADF (−10 ± 4 ng/ml, P < 0.05) and exercise group (−11 ± 4 ng/ml, P < 0.05). Adiponectin was not changed by any intervention. Changes in FMD in the ADF group were not related to changes in leptin. Conclusions These findings suggest that ADF alone is an effective intervention to improve vascular endothelial function. However, the role of adipokines in mediating this effect is still unclear.
    e-SPEN Journal. 01/2013; 8(5):e205–e209.
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    ABSTRACT: BACKGROUND: Intermittent fasting (IF; severe restriction 1 d/week) facilitates weight loss and improves coronary heart disease (CHD) risk indicators. The degree to which weight loss can be enhanced if IF is combined with calorie restriction (CR) and liquid meals, remains unknown. OBJECTIVE: This study examined the effects of IF plus CR (with or without a liquid diet) on body weight, body composition, and CHD risk. METHODS: Obese women (n = 54) were randomized to either the IFCR-liquid (IFCR-L) or IFCR-food based (IFCR-F) diet. The trial had two phases: 1) 2-week weight maintenance period, and 2) 8-week weight loss period. RESULTS: Body weight decreased more (P = 0.04) in the IFCR-L group (3.9 +/- 1.4 kg) versus the IFCR-F group (2.5 +/- 0.6 kg). Fat mass decreased similarly (P < 0.0001) in the IFCR-L and IFCR-F groups (2.8 +/- 1.2 kg and 1.9 +/- 0.7 kg, respectively). Visceral fat was reduced (P < 0.001) by IFCR-L (0.7 +/- 0.5 kg) and IFCR-F (0.3 +/- 0.5 kg) diets. Reductions in total and LDL cholesterol levels were greater (P = 0.04) in the IFCR-L (19 +/- 10%; 20 +/- 9%, respectively) versus the IFCR-F group (8 +/- 3%; 7 +/- 4%, respectively). LDL peak particle size increased (P < 0.01), while heart rate, glucose, insulin, and homocysteine decreased (P < 0.05), in the IFCR-L group only. CONCLUSION: These findings suggest that IF combined with CR and liquid meals is an effective strategy to help obese women lose weight and lower CHD risk.
    Nutrition Journal 11/2012; 11(1):98. · 2.65 Impact Factor
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    ABSTRACT: BACKGROUND: The ability of an intermittent fasting (IF)-calorie restriction (CR) regimen (with or without liquid meals) to modulate adipokines in a way that is protective against coronary heart disease (CHD) has yet to be tested. OBJECTIVE: Accordingly, we examined the effects of an IFCR diet on adipokine profile, body composition, and markers of CHD risk in obese women. METHODS: Subjects (n = 54) were randomized to either the IFCR-liquid (IFCR-L) or IFCR-food based (IFCR-F) diet for 10 weeks. RESULTS: Greater decreases in body weight and waist circumference were noted in the IFCR-L group (4 +/- 1 kg; 6 +/- 1 cm) versus the IFCR-F group (3 +/- 1 kg; 4 +/- 1 cm). Similar reductions (P < 0.0001) in fat mass were demonstrated in the IFCR-L (3 +/- 1 kg) and IFCR-F group (2 +/- 1 kg). Reductions in total and LDL cholesterol levels were greater (P = 0.04) in the IFCR-L (19 +/- 10%; 20 +/- 9%, respectively) versus the IFCR-F group (8 +/- 3%; 7 +/- 4%, respectively). LDL peak particle size increased (P < 0.01) in the IFCR-L group only. The proportion of small LDL particles decreased (P < 0.01) in both groups. Adipokines, such as leptin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and insulin-like growth factor-1 (IGF-1) decreased (P < 0.05), in the IFCR-L group only. CONCLUSION: These findings suggest that IFCR with a liquid diet favorably modulates visceral fat and adipokines in a way that may confer protection against CHD.
    Nutrition & Metabolism 10/2012; 9(1):98. · 3.16 Impact Factor
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    ABSTRACT: BACKGROUND: The Daniel Fast is a vegan diet that prohibits the consumption of animal products, refined foods, white flour, preservatives, additives, sweeteners, flavorings, caffeine, and alcohol. Following this dietary plan for 21 days has been demonstrated to improve blood pressure, LDL-C, and certain markers of oxidative stress, but it has also been shown to lower HDL-C. Krill oil supplementation has been shown to increase HDL-C. METHODS: We investigated the effects of following a Daniel Fast dietary plan with either krill oil supplementation (2 g/day) or placebo supplementation (coconut oil; 2 g/day) for 21 days. The subjects in this study (12 men and 27 women) were heterogeneous with respect to body mass index (BMI) (normal weight, overweight, and obese), blood lipids (normolipidemic and hyperlipidemic), blood glucose (normal fasting glucose, impaired fasting glucose, and type 2 diabetic), and blood pressure (normotensive and hypertensive). RESULTS: Krill oil supplementation had no effect on any outcome measure (all p > 0.05), and so the data from the krill oil group and the placebo group were collapsed and analyzed to examine the effects of following a 21-day Daniel Fast. Significant reductions were observed in LDL-C (100.6 +/- 4.3 mg/dL vs. 80.0 +/- 3.7 mg/dL), the LDL:HDL ratio (2.0 +/- 0.1 vs. 1.7 +/- 0.1), fasting blood glucose (101.4 +/- 7.5 mg/dL vs. 91.7 +/- 3.4 mg/dL), fasting blood insulin (7.92 +/- 0.80 muU/mL vs. 5.76 +/- 0.59 muU/mL), homeostasis model assessment of insulin resistance (HOMA-IR) (2.06 +/- 0.30 vs. 1.40 +/- 0.21), systolic BP (110.7 +/- 2.2 mm Hg vs. 105.5 +/- 1.7 mm Hg), and body weight (74.1 +/- 2.4 kg vs. 71.5 +/- 2.3 kg) (all p < 0.05). CONCLUSION: Following a Daniel Fast dietary plan improves a variety of cardiometabolic parameters in a wide range of individuals in as little as 21 days, and these improvements are unaffected by krill oil supplementation.Trial registrationClinicaltrial.govNCT01378767.
    Nutrition & Metabolism 09/2012; 9(1):82. · 3.16 Impact Factor
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    ABSTRACT: We have recently reported that short-term (21-day) dietary modification in accordance with a stringent vegan diet (i.e., a Daniel Fast) lowers blood lipids as well as biomarkers of oxidative stress. However, this work only involved measurements obtained in a fasted state. In the present study, we determined the postprandial response to a high-fat milkshake with regards to blood triglycerides (TAG), biomarkers of oxidative stress, and hemodynamic variables before and following a 21-day Daniel Fast. Twenty-two subjects (10 men and 12 women; aged 35 ± 3 years) completed a 21-day Daniel Fast. To induce oxidative stress, a milkshake (fat = 0.8 g·kg-1; carbohydrate = 1.0 g·kg-1; protein = 0.25 g·kg-1) was consumed by subjects on day one and day 22 in a rested and 12-hour fasted state. Before and at 2 and 4 h after consumption of the milkshake, heart rate (HR) and blood pressure were measured. Blood samples were also collected at these times and analyzed for TAG, malondialdehyde (MDA), hydrogen peroxide (H2O2), advanced oxidation protein products (AOPP), nitrate/nitrite (NOx), and Trolox Equivalent Antioxidant Capacity (TEAC). A time effect was noted for HR (p = 0.006), with values higher at 2 hr post intake of the milkshake as compared to pre intake (p < 0.05). Diastolic blood pressure was lower post fast as compared to pre fast (p = 0.02), and a trend for lower systolic blood pressure was noted (p = 0.07). Time effects were noted for TAG (p = 0.001), MDA (p < 0.0001), H2O2 (p < 0.0001), AOPP (p < 0.0001), and TEAC (p < 0.0001); all concentrations were higher at 2 h and 4 h post intake compared to pre intake, except for TEAC, which was lower at these times (p < 0.05). A condition effect was noted for NOx (p = 0.02), which was higher post fast as compared to pre fast. No pre/post fast × time interactions were noted (p > 0.05), with the area under the curve from pre to post fast reduced only slightly for TAG (11%), MDA (11%), H2O2 (8%), and AOPP (12%), with a 37% increase noted for NOx. Partaking in a 21-day Daniel Fast does not result in a statistically significant reduction in postprandial oxidative stress. It is possible that a longer time course of adherence to the Daniel Fast eating plan may be needed to observe significant findings.
    Nutrition Journal 03/2012; 11:16. · 2.65 Impact Factor
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    ABSTRACT: Trepanowski, JF, Farney, TM, McCarthy, CG, Schilling, BK, Craig, SA, and Bloomer, RJ. The effects of chronic betaine supplementation on exercise performance, skeletal muscle oxygen saturation, and associated biochemical parameters in resistance trained men. J Strength Cond Res 25(12): 3461-3471, 2011-We examined the effects of chronic betaine supplementation on exercise performance and associated parameters in resistance trained men. Men were randomly assigned in a double-blind manner using a crossover design to consume betaine (2.5 g of betaine mixed in 500 ml of Gatorade®) or a placebo (500 ml of Gatorade®) for 14 days, with a 21-day washout period. Before and after each treatment period, tests of lower- and upper-body muscular power and isometric force were conducted, including a test of upper-body muscular endurance (10 sets of bench press exercise to failure). Muscle tissue oxygen saturation (StO2) during the bench press protocol was measured via near infrared spectroscopy. Blood samples were collected before and after the exercise test protocol for analysis of lactate, nitrate/nitrite (NOx), and malondialdehyde (MDA). When analyzed using a repeated measures analysis of variance, no significant differences were noted between conditions for exercise performance variables (p > 0.05). However, an increase in total repetitions (p = 0.01) and total volume load (p = 0.02) in the 10-set bench press protocol was noted with betaine supplementation (paired t-tests), with values increasing approximately 6.5% from preintervention to postintervention. Although not of statistical significance (p = 0.14), postexercise blood lactate increased to a lesser extent with betaine supplementation (210%) compared with placebo administration (270%). NOx was lower postintervention as compared with preintervention (p = 0.06), and MDA was relatively unchanged. The decrease in StO2 during the bench press protocol was greater with betaine vs. placebo (p = 0.01), possibly suggesting enhanced muscle oxygen consumption. These findings indicate that betaine supplementation results in a moderate increase in total repetitions and volume load in the bench press exercise, without favorably impacting other performance measures.
    The Journal of Strength and Conditioning Research 11/2011; 25(12):3461-71. · 1.80 Impact Factor
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    ABSTRACT: The aim of this study was to assess the effects of Ramadan fasting on several biochemical and anthropometric parameters in physically active men by comparing fasters and nonfasters before, during, and after Ramadan. Eighteen physically active men (10 fasters and 8 nonfasters) participated in this study. Subjects visited the laboratory for a total of four sessions on the following occasions: three days before Ramadan (Bef-R), the 15(th) day of Ramadan (Mid-R), the 29(th) day of Ramadan (End-R), and 21 days after Ramadan (Post-R). During each session, subjects underwent anthropometric measurements, completed a dietary questionnaire and provided a fasting blood sample. Body weight and body fat percentage decreased in fasters by 1.9% (P<0.001) and 6.2% (P=0.003), respectively, but increased in nonfasters by 2.2% (P<0.001) and 10.2% (P=0.001), respectively, from Bef-R to End-R. Fasters' hematocrit and hemoglobin increased by 5.3% (P<0.001) and 6.3% (P=0.01), respectively, from Bef-R to End-R, while neither of these parameters changed in nonfasters. Fasters experienced an increase in the following parameters from Bef-R to End-R: urea (8.7%; P<0.001), creatinine (7.5%; P<0.001), uric acid (12.7%; P<0.001), serum sodium (1.9%; P<0.001), serum chloride (2.6%; P<0.001) and high-density lipoprotein cholesterol (27.3%; P<0.001). Of these parameters, only creatinine increased (4.4%; P=0.01) in nonfasters. We conclude that Ramadan fasting lowers body weight and body fat percentage and can elevate high-density lipoprotein cholesterol in physically active men. However, practicing aerobic exercise during a hot and humid Ramadan month can induce a state of dehydration marked by an increase in some renal function markers and serum electrolytes.
    Asian journal of sports medicine. 09/2011; 2(3):134-44.
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    ABSTRACT: Betaine, beetroot juice, and supplemental nitrate have recently been reported to improve certain aspects of exercise performance, which may be mechanistically linked to increased nitric oxide. The purpose of the present study was to investigate the effect of betaine supplementation on plasma nitrate/nitrite, a surrogate marker or nitric oxide, in exercise-trained men. We used three different study designs (acute intake of betaine at 1.25 and 5.00 grams, chronic intake of betaine at 2.5 grams per day for 14 days, and chronic [6 grams of betaine per day for 7 days] followed by acute intake [6 grams]), all involving exercise-trained men, to investigate the effects of orally ingested betaine on plasma nitrate/nitrite. Blood samples were collected before and at 30, 60, 90, and 120 min after ingestion of 1.25 and 5.00 grams of betaine (Study 1); before and after 14 days of betaine supplementation at a dosage of 2.5 grams (Study 2); and before and after 7 days of betaine supplementation at a dosage of 6 grams, followed by acute ingestion of 6 grams and blood measures at 30 and 60 min post ingestion (Study 3). In Study 1, nitrate/nitrite was relatively unaffected and no statistically significant interaction (p = 0.99), dosage (p = 0.69), or time (p = 0.91) effects were noted. Similar findings were noted in Study 2, with no statistically significant interaction (p = 0.57), condition (p = 0.98), or pre/post intervention (p = 0.17) effects noted for nitrate/nitrite. In Study 3, no statistically significant changes were noted in nitrate/nitrite between collection times (p = 0.97). Our data indicate that acute or chronic ingestion of betaine by healthy, exercise-trained men does not impact plasma nitrate/nitrite. These findings suggest that other mechanisms aside from increasing circulating nitric oxide are likely responsible for any performance enhancing effect of betaine supplementation.
    Journal of the International Society of Sports Nutrition 03/2011; 8:5. · 1.83 Impact Factor
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    ABSTRACT: Dietary modification via both caloric and nutrient restriction is associated with multiple health benefits, some of which are related to an improvement in antioxidant status and a decrease in the production of reactive oxygen species. The Daniel Fast is based on the Biblical book of Daniel, is commonly partaken for 21 days, and involves food intake in accordance with a stringent vegan diet. The purpose of the present study was to determine the effect of a 21 day Daniel Fast on biomarkers of antioxidant status and oxidative stress. 43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day Daniel Fast following the guidelines provided by investigators. Subjects reported to the lab in a 12 hour post-absorptive state both pre fast (day 1) and post fast (day 22). At each visit, blood was collected for determination of malondialdehyde (MDA), hydrogen peroxide (H2O2), nitrate/nitrite (NOx), Trolox Equivalent Antioxidant Capacity (TEAC), and Oxygen Radical Absorbance Capacity (ORAC). Subjects recorded dietary intake during the 7 day period immediately prior to the fast and during the final 7 days of the fast. A decrease was noted in MDA (0.66 ± 0.0.03 vs. 0.56 ± 0.02 μmol L-1; p = 0.004), while H2O2 demonstrated a trend for lowering (4.42 ± 0.32 vs. 3.78 ± 0.21 μmol L-1; p = 0.074). Both NOx (18.79 ± 1.92 vs. 26.97 ± 2.40 μmol L-1; p = 0.003) and TEAC (0.47 ± 0.01 vs. 0.51 ± 0.01 mmol L-1; p = 0.001) increased from pre to post fast, while ORAC was unchanged (5243 ± 103 vs. 5249 ± 183 μmol L-1 TE; p = 0.974). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total calorie intake (2185 ± 94 vs. 1722 ± 85). Modification of dietary intake in accordance with the Daniel Fast is associated with an improvement in selected biomarkers of antioxidant status and oxidative stress, including metabolites of nitric oxide (i.e., NOx).
    Nutrition & Metabolism 03/2011; 8:17. · 3.16 Impact Factor
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    ABSTRACT: Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.
    Nutrition Journal 01/2011; 10:107. · 2.65 Impact Factor
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    ABSTRACT: Purpose: The aim of this study was to assess the effects of Ramadan fasting on several biochemical and anthropometric parameters in physically active men by comparing fasters and nonfasters before, during, and after Ramadan. Methods: Eighteen physically active men (10 fasters and 8 nonfasters) participated in this study. Subjects visited the laboratory for a total of four sessions on the following occasions: three days before Ramadan (Bef-R), the 15 th day of Ramadan (Mid-R), the 29 th day of Ramadan (End-R), and 21 days after Ramadan (Post-R). During each session, subjects underwent anthropometric measurements, completed a dietary questionnaire and provided a fasting blood sample. Results: Body weight and body fat percentage decreased in fasters by 1.9% (P<0.001) and 6.2% (P=0.003), respectively, but increased in nonfasters by 2.2% (P<0.001) and 10.2% (P=0.001), respectively, from Bef-R to End-R. Fasters' hematocrit and hemoglobin increased by 5.3% (P<0.001) and 6.3% (P=0.01), respectively, from Bef-R to End-R, while neither of these parameters changed in nonfasters. Fasters experienced an increase in the following parameters from Bef-R to End-R: urea (8.7%; P<0.001), creatinine (7.5%; P<0.001), uric acid (12.7%; P<0.001), serum sodium (1.9%; P<0.001), serum chloride (2.6%; P<0.001) and high-density lipoprotein cholesterol (27.3%; P<0.001). Of these parameters, only creatinine increased (4.4%; P=0.01) in nonfasters. Conclusions: We conclude that Ramadan fasting lowers body weight and body fat percentage and can elevate high-density lipoprotein cholesterol in physically active men. However, practicing aerobic exercise during a hot and humid Ramadan month can induce a state of dehydration marked by an increase in some renal function markers and serum electrolytes.
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    ABSTRACT: We compared Glycine Propionyl-L-Carnitine (GlycoCarn(R)) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men. Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn(R), or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO2 was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set. A condition effect was noted for StO2 at the start of exercise (p = 0.02), with GlycoCarn(R) higher than SUPP2. A condition effect was also noted for StO2 at the end of exercise (p = 0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05); however, MDA decreased 13.7% with GlycoCarn(R) and increased in all other conditions. Only a time effect was noted for HLa (p < 0.0001), with values increasing from pre- to post-exercise. No effects were noted for HR, RPE, or for any exercise performance variables (p > 0.05); however, GlycoCarn(R) resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%). None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn(R) in terms of higher StO2 at the start of exercise. GlycoCarn(R) resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn(R)) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.
    Journal of the International Society of Sports Nutrition 01/2010; 7:16. · 1.83 Impact Factor
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    John F Trepanowski, Richard J Bloomer
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    ABSTRACT: The past two decades have seen a rise in the number of investigations examining the health-related effects of religiously motivated fasts. Islamic Ramadan is a 28 - 30 day fast in which food and drink are prohibited during the daylight hours. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings are the differences between studies in the following: 1) the amount of daily fasting time; 2) the percentage of subjects who smoke, take oral medications, and/or receive intravenous fluids; and 3) the subjects' typical food choices and eating habits. Greek Orthodox Christians fast for a total of 180 - 200 days each year, and their main fasting periods are the Nativity Fast (40 days prior to Christmas), Lent (48 days prior to Easter), and the Assumption (15 days in August). The fasting periods are more similar than dissimilar, and they can each be described as a variant of vegetarianism. Some of the more favorable effects of these fasts include the lowering of body mass, total cholesterol, LDL-C, and the LDL-C/HDL-C ratio. The Biblical-based Daniel Fast prohibits the consumption of animal products, refined carbohydrates, food additives, preservatives, sweeteners, flavorings, caffeine, and alcohol. It is most commonly partaken for 21 days, although fasts of 10 and 40 days have been observed. Our initial investigation of the Daniel Fast noted favorable effects on several health-related outcomes, including: blood pressure, blood lipids, insulin sensitivity, and biomarkers of oxidative stress. This review summarizes the health-specific effects of these fasts and provides suggestions for future research.
    Nutrition Journal 01/2010; 9:57. · 2.65 Impact Factor
  • Medicine and Science in Sports and Exercise - MED SCI SPORT EXERCISE. 01/2010; 42.
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    ABSTRACT: Dietary modification via caloric restriction is associated with multiple effects related to improved metabolic and cardiovascular health. However, a mandated reduction in kilocalories is not well-tolerated by many individuals, limiting the long-term application of such a plan. The Daniel Fast is a widely utilized fast based on the Biblical book of Daniel. It involves a 21 day ad libitum food intake period, devoid of animal products and preservatives, and inclusive of fruits, vegetables, whole grains, legumes, nuts, and seeds. The purpose of the present study was to determine the efficacy of the Daniel Fast to improve markers of metabolic and cardiovascular disease risk. 43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day period of modified food intake in accordance with detailed guidelines provided by investigators. All subjects purchased and prepared their own food. Following initial screening, subjects were given one week to prepare for the fast, after which time they reported to the lab for their pre-intervention assessment (day 1). After the 21 day fast, subjects reported to the lab for their post-intervention assessment (day 22). For both visits, subjects reported in a 12 hr fasted state, performing no strenuous physical activity during the preceding 24-48 hrs. At each visit, mental and physical health (SF-12 form), resting heart rate and blood pressure, and anthropometric variables were measured. Blood was collected for determination of complete blood count, metabolic panel, lipid panel, insulin, HOMA-IR, and C-reactive protein (CRP). Subjects' self-reported compliance, mood, and satiety in relation to the fast were also recorded. Diet records were maintained by all subjects during the 7 day period immediately prior to the fast (usual intake) and during the final 7 days of the fast. Subjects' compliance to the fast was 98.7 ± 0.2% (mean ± SEM). Using a 10 point scale, subjects' mood and satiety were both 7.9 ± 0.2. The following variables were significantly (p < 0.05) lower following the fast as compared to before the fast: white blood cell count (5.68 ± 0.24 vs. 4.99 ± 0.19 103.μL-1), blood urea nitrogen (13.07 ± 0.58 vs. 10.14 ± 0.59 mg.dL-1), blood urea nitrogen/creatinine (14.74 ± 0.59 vs. 11.67 ± 0.68), protein (6.95 ± 0.07 vs. 6.77 ± 0.06 g.dL-1), total cholesterol (171.07 ± 4.57 vs. 138.69 ± 4.39 mg.dL-1), LDL-C (98.38 ± 3.89 vs. 76.07 ± 3.53 mg.dL-1), HDL-C (55.65 ± 2.50 vs. 47.58 ± 2.19 mg.dL-1), SBP (114.65 ± 2.34 vs. 105.93 ± 2.12 mmHg), and DBP (72.23 ± 1.59 vs. 67.00 ± 1.43 mmHg). Insulin (4.42 ± 0.52 vs. 3.37 ± 0.35 μU.mL-1; p = 0.10), HOMA-IR (0.97 ± 0.13 vs.0.72 ± 0.08; p = 0.10), and CRP (3.15 ± 0.91 vs. 1.60 ± 0.42 mg.L-1; p = 0.13), were lowered to a clinically meaningful, albeit statistically insignificant extent. No significant difference was noted for any anthropometric variable (p > 0.05). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total kilocalorie intake (2185 ± 94 vs. 1722 ± 85). A 21 day period of modified dietary intake in accordance with the Daniel Fast is 1) well-tolerated by men and women and 2) improves several risk factors for metabolic and cardiovascular disease. Larger scale, randomized studies, inclusive of a longer time period and possibly a slight modification in food choice in an attempt to maintain HDL cholesterol, are needed to extend these findings.
    Lipids in Health and Disease 01/2010; 9:94. · 2.02 Impact Factor