John Trepanowski

University of Illinois at Chicago | UIC · Department of Kinesiology and Nutrition

This study compared the weight loss efficacy of alternate-day fasting (ADF) versus daily calorie restriction (CR) in adults with subclinical hypothyroidism. After 6 months, body weight decreased (P < 0.001) similarly by ADF (–7% ± 1%) and CR (–8% ± 2%). Insulin resistance decreased (P < 0.05) more by ADF versus CR. Free thyroxin and thyroid-stimula...

Objective: This study compared the effects of alternate-day fasting (ADF) with those of daily calorie restriction (CR) on body weight and glucoregulatory factors in adults with overweight or obesity and insulin resistance. Methods: This secondary analysis examined the data of insulin-resistant individuals (n = 43) who participated in a 12-month...

Background: Alternate-day fasting (ADF) involves a 'famine day' (25% energy intake) and a 'feast day' (ad libitum intake). This secondary analysis examined changes in beverage intake in relation to energy intake and body weight during 12 months of ADF versus daily calorie restriction (CR). Methods: Obese subjects (n = 100 enrolled, n = 69 comple...

Background and aims: The receptor for advanced glycation end products (RAGE) is implicated in obesogenesis. Conversely, soluble RAGE (sRAGE) competitively inhibits RAGE. Our aim was to determine the effects of weight-loss via alternate day fasting (ADF) on sRAGE isoforms and evaluate potential relationships with body composition. Methods and resu...

In Reply The letters by Dr Ludwig and colleagues and Drs Bero and Grundy offer an opportunity to discuss potential trade-offs and clarify potential misunderstandings regarding our proposal.

Background: Time restricted feeding decreases energy intake without calorie counting and may be a viable option for weight loss. However, the effect of this diet on body weight in obese subjects has never been examined. Objective: This study investigated the effects of 8-h time restricted feeding on body weight and metabolic disease risk factors...

Importance Dietary modification remains key to successful weight loss. Yet, no one dietary strategy is consistently superior to others for the general population. Previous research suggests genotype or insulin-glucose dynamics may modify the effects of diets. Objective To determine the effect of a healthy low-fat (HLF) diet vs a healthy low-carboh...

Background: Alternate-day fasting (ADF) has gained popularity in recent years. The diet consists of a "fast day" where an individual consumes 0-25% of their energy needs, alternated with a "feast day" where a person is permitted to eat ad libitum. Aim: This study examined eating behavior traits of successful weight losers during alternate day fa...

Background & aims: Indirect comparisons suggest that alternate-day fasting (ADF) may produce greater improvements in body composition, fat distribution, and/or the adipokine profile compared to daily calorie restriction (CR), but this has not been tested directly. In a pre-planned secondary analysis of a randomized controlled trial, we compared ch...

In Reply Dr Portillo-Sanchez and colleagues have pointed to limitations in our study¹ that, although previously discussed in the main article, are important enough to merit extra discussion. These limitations include sample size, dropout rate in the alternate-day fasting group, and (mostly) metabolically healthy trial participants. Dr Portillo-Sanc...

BACKGROUND Alternate day fasting (ADF) is a novel diet therapy that reduces body weight, but its effect on bone health remains unknown. OBJECTIVE This study examined the impact of ADF versus traditional daily calorie restriction (CR) on markers of bone metabolism in a 6-month randomized controlled trial. METHODS Overweight and obese subjects (n =...

Importance: Alternate-day fasting has become increasingly popular, yet, to date, no long-term randomized clinical trials have evaluated its efficacy. Objective: To compare the effects of alternate-day fasting vs daily calorie restriction on weight loss, weight maintenance, and risk indicators for cardiovascular disease. Design, setting, and par...

Background: Dietary modification remains an essential component of successful weight loss strategies. No one dietary strategy has been determined to be superior to others for the general population. Studies that contrast reducing dietary fat vs. carbohydrate report consistently high within-group variability in dietary adherence and weight loss. Pre...

Background: The abilities of healthy low fat (HLF) and healthy low carbohydrate (HLC) weight loss diets to improve insulin sensitivity over the long term are not well understood. Objective: To examine whether HLF and HLC weight loss diets improve insulin sensitivity over 12 months, and to determine if either diet is superior for these improvements....

Background & aims: Alternate day fasting (ADF; 25% energy intake "fast day", alternated with an ad libitum intake "feed day") is effective for weight loss. Whether or not ADF modulates hunger, fullness and gut peptides in a way that enhances dietary compliance and weight loss, remains unknown. Accordingly, this study examined the effect of ADF on...

This study examined what characteristics predict weight loss success with alternate day fasting (ADF). Four 8-week trials of ADF (n=121) were included in the analysis. Subjects aged 50-59 y achieved greater (P=0.01) weight loss than other age groups. Males and females achieved similar weight loss. Caucasian subjects achieved greater (P=0.03) weight...

Background Alternate day fasting (ADF; ad libitum intake “feed day” alternated with 75% restriction “fast day”), is effective for weight loss, but the safety of the diet has been questioned. Accordingly, this study examined occurrences of adverse events and eating disorder symptoms during ADF. Findings Obese subjects (n = 59) participated in an 8-...

Fetuin-A (FetA) is a 64-kDa glycoprotein that is secreted from both the liver and adipose tissue. Circulating FetA is elevated in obesity and related disorders including type 2 diabetes mellitus, nonalcoholic fatty liver disease, and the metabolic syndrome; and a FetA-related parameter, caliciprotein particle, is highly relevant to vascular calcifi...

Objective Alternate day fasting (ADF; 24-h feeding/24-h 25% energy intake at lunchtime), is effective for weight loss, but diet tolerability is questionable. Moving the fast day meal to dinnertime, or dividing it into smaller meals, may improve tolerability. Accordingly, this study compared the effects of ADF with three meal times on body weight an...

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 glyc...

Visceral adiposity is associated with several metabolic abnormalities, and diet-induced reduction of visceral fat improves many of these abnormalities. Daily calorie restriction (DCR) is a popular weight loss diet that reduces energy intake by 15-40% every day. Intermittent calorie restriction (ICR) is an alternative weight loss diet that produces...

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 no...

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,...

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,...

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...

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. Design and methods: Obese subjects (n = 64) were randomized to 1 of 4 groups for 12 weeks: 1) combination (ADF plus endurance exercise)...

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. This study examined the effects of IF plus CR (with or without a liquid diet) on...

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. Accordingly, we examined the effects of an IFCR diet on adipokine profile, body composition, and markers of CHD risk in obese women....

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...

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 m...

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...

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) consis...

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 o...

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 e...

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...

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 labora...

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...

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...

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 p...