Changes in energy and macronutrient intakes during Ramadan fasting: a systematic review, meta-analysis, and meta-regression.

CONTEXT: Ramadan fasting (RF) is associated with various physiological and metabolic changes among fasting Muslims. However, it remains unclear whether these effects are attributable to changes in meal timing or changes in dietary energy and macronutrient intakes. Furthermore, the literature on the associations between RF, meal timing, and energy and macronutrient intakes is inconclusive. OBJECTIVES: This systematic review aimed to estimate the effect sizes of RF on energy and macronutrient intakes (carbohydrates, protein, fats, dietary fiber, and water) and determine the effect of different moderators on the examined outcomes. DATA SOURCES: The Cochrane, CINAHL, EMBASE, EBSCOhost, Google Scholar, PubMed/MEDLINE, ProQuest Medical, Scopus, ScienceDirect, and Web of Science databases were searched from inception to January 31, 2022. DATA EXTRACTION: The studies that assessed energy, carbohydrate, protein, fat, fiber, and water intakes pre- and post-fasting were extracted. DATA ANALYSIS: Of the 4776 identified studies, 85 relevant studies (n = 4594 participants aged 9-85 y) were selected. The effect sizes for the studied variables were as follows: energy (number of studies [K] = 80, n = 3343 participants; mean difference [MD]: -142.45; 95% confidence interval [CI]: -215.19, -69.71), carbohydrates (K = 75, n = 3111; MD: -23.90; 95% CI: -36.42, -11.38), protein (K = 74, n = 3108; MD: -4.21; 95% CI: -7.34, -1.07), fats (K = 73, n = 3058; MD: -2.03; 95% CI: -5.73, 1.67), fiber (K = 16, n = 1198; MD: 0.47; 95% CI: -1.44, 2.39), and water (K = 17, n = 772; MD: -350.80; 95% CI: -618.09, 83.50). Subgroup analyses showed age significantly moderated the 6 dietary outcomes, and physical activity significantly moderated water intake. There were significant reductions in energy, carbohydrate, and protein intakes during RF. CONCLUSIONS: The change in meal timing rather than quantitative dietary intake may explain various physiological and health effects associated with RF.

Intermittent fasting interventions to leverage metabolic and circadian mechanisms for cancer treatment and supportive care outcomes.

Intermittent fasting entails restricting food intake during specific times of day, days of the week, religious practice, or surrounding clinically important events. Herein, the metabolic and circadian rhythm mechanisms underlying the proposed benefits of intermittent fasting for the cancer population are described. We summarize epidemiological, preclinical, and clinical studies in cancer published between January 2020 and August 2022 and propose avenues for future research. An outstanding concern regarding the use of intermittent fasting among cancer patients is that fasting often results in caloric restriction, which can put patients already prone to malnutrition, cachexia, or sarcopenia at risk. Although clinical trials do not yet provide sufficient data to support the general use of intermittent fasting in clinical practice, this summary may be useful for patients, caregivers, and clinicians who are exploring intermittent fasting as part of their cancer journey for clinical outcomes and symptom management.

Imaging modalities for measuring body composition in patients with cancer: opportunities and challenges.

Body composition assessment (ie, the measurement of muscle and adiposity) impacts several cancer-related outcomes including treatment-related toxicities, treatment responses, complications, and prognosis. Traditional modalities for body composition measurement include body mass index, body circumference, skinfold thickness, and bioelectrical impedance analysis; advanced imaging modalities include dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and positron emission tomography. Each modality has its advantages and disadvantages, thus requiring an individualized approach in identifying the most appropriate measure for specific clinical or research situations. Advancements in imaging approaches have led to an abundance of available data, however, the lack of standardized thresholds for classification of abnormal muscle mass or adiposity has been a barrier to adopting these measurements widely in research and clinical care. In this review, we discuss the different modalities in detail and provide guidance on their unique opportunities and challenges.

Alternate-Day Fasting Combined with Exercise: Effect on Sleep in Adults with Obesity and NAFLD.

Objective: This study investigated how alternate-day fasting (ADF) combined with aerobic exercise impacts body weight and sleep in adults with non-alcoholic fatty liver disease (NAFLD). Methods: Adults with obesity and NAFLD (n = 80) were randomized into one of four groups for 3 months: combination of ADF (600 kcal "fast day," alternated with an ad libitum intake "feast day") and moderate-intensity aerobic exercise (five sessions per week, 60 min/session); ADF alone; exercise alone; or a no-intervention control group. Results: By month 3, body weight and intrahepatic triglyceride content decreased (p < 0.001, group × time interaction) in the combination group versus the exercise group and control group, but not versus the ADF group. Sleep quality, measured by the Pittsburgh Sleep Quality Inventory (PSQI), did not change in the combination group (baseline: 6.0 ± 0.7; month 3: 5.6 ± 0.7), ADF group (baseline: 8.9 ± 1.0; month 3: 7.5 ± 0.8), or exercise group (baseline: 6.4 ± 0.6; month 3: 6.7 ± 0.6), versus controls (baseline: 5.5 ± 0.7; month 3: 4.6 ± 0.5). Wake time, bedtime, sleep duration, and insomnia severity did not change (no group x time interaction) over the course of the study in any group. Risk for obstructive sleep apnea was present in 30% of combination subjects, 75% of ADF subjects, 40% of exercise subjects, and 75% of controls, and did not change in the intervention groups, versus controls, by month 3. No associations were observed between changes in body weight, intrahepatic triglyceride content, and any sleep outcome. Conclusions: The weight loss induced by ADF combined with exercise does not improve sleep quality, duration, insomnia severity, or risk of obstructive sleep apnea in individuals with NAFLD.

Effect of alternate day fasting combined with aerobic exercise on non-alcoholic fatty liver disease: A randomized controlled trial.

Innovative non-pharmacological lifestyle strategies to treat non-alcoholic fatty liver disease (NAFLD) are critically needed. This study compared the effects of alternate day fasting (ADF) combined with exercise to fasting alone, or exercise alone, on intrahepatic triglyceride (IHTG) content. Adults with obesity and NAFLD (n = 80, 81% female, age: 23-65 years) were randomized to 1 of 4 groups for 3 months: combination of ADF (600 kcal/2,500 kJ "fast day" alternated with an ad libitum intake "feast day") and moderate-intensity aerobic exercise (5 session per week, 60 min/session); ADF alone; exercise alone; or a no-intervention control group. By month 3, IHTG content was significantly reduced in the combination group (-5.48%; 95% CI, -7.77% to -3.18%), compared with the exercise group (-1.30%; 95% CI, -3.80% to 1.20%; p = 0.02) and the control group (-0.17%; 95% CI, -2.17% to 1.83%; p < 0.01) but was not significantly different versus the ADF group (-2.25%; 95% CI, -4.46% to -0.04%; p = 0.05). Body weight, fat mass, waist circumference, and alanine transaminase (ALT) levels significantly decreased, while insulin sensitivity significantly increased in the combination group compared with the control group. Lean mass, aspartate transaminase (AST), HbA1c, blood pressure, plasma lipids, liver fibrosis score, and hepatokines (fetuin-A, FGF-21, and selenoprotein P) did not differ between groups. Combining intermittent fasting with exercise is effective for reducing hepatic steatosis in patients with NAFLD but may offer no additional benefit versus fasting alone.

Effect of time-restricted eating on sex hormone levels in premenopausal and postmenopausal females.

OBJECTIVE: Concerns have been raised regarding the impact of time-restricted eating (TRE) on sex hormones in females. This study examined how TRE affects sex steroids in premenopausal and postmenopausal females. METHODS: This is a secondary analysis of an 8-week TRE study (4- to 6-hour eating window) conducted in adults with obesity. Men and perimenopausal females were excluded. Females were classified into two groups based on menstrual status: premenopausal (n = 12) or postmenopausal (n = 11). RESULTS: After 8 weeks, body weight decreased in premenopausal females (-3% ± 2%) and postmenopausal females (-4% ± 2%) (main effect of time, p < 0.001), with no difference between groups (no group × time interaction). Circulating levels of testosterone, androstenedione, and sex hormone binding globulin (SHBG) did not change in either group (no group × time interaction). Dehydroepiandrosterone (DHEA) concentrations decreased (p < 0.05) in premenopausal (-14% ± 32%) and postmenopausal females (-13% ± 34%; main effect of time, p = 0.03), with no difference between groups. Estradiol, estrone, and progesterone were measured only in postmenopausal females, and they remained unchanged. CONCLUSIONS: In premenopausal females, androgens and SHBG remained unchanged during TRE, whereas DHEA decreased. In postmenopausal females, estrogens, progesterone, androgens, and SHBG did not change, but DHEA was reduced.

Validation and results of a novel survey assessing decisional balance for a whole food plant-based diet among US adults.

Importance: Consuming a whole food plant-based diet (WFPBD) is a promising, low-risk strategy for reducing risk of prevalent chronic disease and certain cancers, with synergistic benefits for climate and environment. However, few US adults report consuming a WFPBD. Understanding the reasons for this inconsistency is important for developing and implementing interventions for promoting a WFPBD. However, no research to elucidate decisional balance driving current consumption patterns in the US exists. Objective: This research aims to validate an online survey to assess decisional balance for the consumption of a WFPBD, describe attitudes and beliefs toward adopting a WFPBD, and evaluate socio-demographic differences in decisional balance for consuming a WFPBD among a convenience sample of US adults. Design: Online cross-sectional data collection followed by confirmatory factor analysis (CFA), validation of internal consistency, and examination of invariance across socio-demographic variables. Sensitivity analysis of full vs. truncated survey to predict self-reported dietary patterns and consumption behaviors were evaluated. Results of the survey and significant differences by socio-demographics were assessed. Setting: Online survey based on previous research, created via Qualtrics, and administered through MTurk. Participants: A total of 412 US adults, majority female (66%), White (75%), 30-60 years old (54%), ≥ Bachelor's degree (85%), and earning ≥ $45K (68%). Main outcomes and measures: Factor loadings, covariance of survey items, associations with self-reported dietary pattern and consumption measures, and differences in pros, cons, and decisional balance across socio-demographic variables. Results: CFA reduced the survey from 49 to 12 items and demonstrated invariance across socio-demographic variables. Pros and cons varied inversely and significantly (cov = -0.59), as expected. Cronbach's α 's for subscales in the final, reduced model were high (>0.80). Pros, cons, and decisional balance in both the full and the reduced model were significantly (p < 0.05) associated with self-reported dietary pattern and consumption. Conclusion and relevance: Our analyses indicate the WFPBD Survey is a parsimonious and psychometrically sound instrument for evaluation of decisional balance to consume a WFPBD diet among our sample of US adults. These results may be instrumental for development and deployment of interventions intended to promote consumption of a WFPBD in the US.

Effect of Intermittent Fasting on Reproductive Hormone Levels in Females and Males: A Review of Human Trials.

Intermittent fasting is a popular diet for weight loss, but concerns have been raised regarding the effects of fasting on the reproductive health of women and men. Accordingly, we conducted this literature review to clarify the effects of fasting on reproductive hormone levels in humans. Our results suggest that intermittent fasting decreases androgen markers (i.e., testosterone and the free androgen index (FAI)) while increasing sex hormone-binding globulin (SHBG) levels in premenopausal females with obesity. This effect was more likely to occur when food consumption was confined to earlier in the day (eating all food before 4 pm). In contrast, fasting did not have any effect on estrogen, gonadotropins, or prolactin levels in women. As for men, intermittent fasting reduced testosterone levels in lean, physically active, young males, but it did not affect SHBG concentrations. Interestingly, muscle mass and muscular strength were not negatively affected by these reductions in testosterone. In interpreting these findings, it is important to note that very few studies have been conducted on this topic. Thus, it is difficult to draw solid conclusions at present. From the limited data presented here, it is possible that intermittent fasting may decrease androgen markers in both genders. If this is the case, these results would have varied health implications. On the one hand, fasting may prove to be a valuable tool for treating hyperandrogenism in females with polycystic ovarian syndrome (PCOS) by improving menstruation and fertility. On the other hand, fasting may be shown to decrease androgens among males, which could negatively affect metabolic health and libido. More research is warranted to confirm these preliminary findings.

The effect of 4-h versus 6-h time restricted feeding on sleep quality, duration, insomnia severity and obstructive sleep apnea in adults with obesity.

BACKGROUND: Time restricted feeding (TRF) involves deliberately restricting the times during which energy is ingested. Preliminary findings suggest that 8-10-h TRF improves sleep. However, the effects of shorter TRF windows (4-6 h) on sleep, remain unknown. AIMS: This study compared the effects of 4-h versus 6-h TRF on sleep quality, duration, insomnia severity and the risk of obstructive sleep apnea. METHODS: Adults with obesity (n = 49) were randomized into one of three groups: 4-h TRF (eating only between 3 and 7 p.m.), 6-h TRF (eating only between 1 and 7 p.m.), or a control group (no meal timing restrictions) for 8 weeks. RESULTS: After 8 weeks, body weight decreased (p < 0.001) similarly by 4-h TRF (-3.9 ± 0.4 kg) and 6-h TRF (-3.4 ± 0.4 kg), versus controls. Sleep quality, measured by the Pittsburgh Sleep Quality Index (PSQI), did not change by 4-h TRF (baseline: 5.9 ± 0.7; week 8: 4.8 ± 0.6) or 6-h TRF (baseline: 6.4 ± 0.8; week 8: 5.3 ± 0.9), versus controls. Wake time, bedtime, sleep duration and sleep onset latency also remained unchanged. Insomnia severity did not change by 4-h TRF (baseline: 4.4 ± 1.0; week 8: 4.7 ± 0.9) or 6-h TRF (baseline: 8.3 ± 1.2; week 8: 5.5 ± 1.1), versus controls. Percent of participants reporting obstructive sleep apnea symptoms did not change by 4-h TRF (baseline: 44%; week 8: 25%) or 6-h TRF (baseline: 47%; week 8: 20%), versus controls. CONCLUSION: These findings suggest that 4- and 6-h TRF have no effect on sleep quality, duration, insomnia severity, or the risk of obstructive sleep apnea.

Changes in body weight and metabolic risk during time restricted feeding in premenopausal versus postmenopausal women.

BACKGROUND: Time restricted feeding (TRF) involves confining the eating window to a specific number of hours, and fasting for the remaining hours of the day. OBJECTIVE: This study examined if changes in body weight and metabolic risk factors during TRF, differ between premenopausal and postmenopausal women. METHODS: This is a secondary analysis of an 8-week TRF study (4-6 h eating window, 18-20 h fasting window daily) conducted in adults with obesity. Male participants were excluded, and female subjects were classified in two groups based on menstrual status: premenopausal (n = 13), or postmenopausal (n = 19). Perimenopausal women were excluded from the original study. RESULTS: Body weight decreased by week 8 in premenopausal women (-3.3 ± 0.4%) and postmenopausal women (-3.3 ± 0.5%) (main effect of time, P < 0.001), with no difference between groups (no group × time interaction). Adherence was excellent in both groups, with premenopausal women adhering to their prescribed eating window on 6.2 ± 0.1 d/week, and postmenopausal women adhering to their window on 6.2 ± 0.2 d/week. Fat mass, lean mass, fasting insulin, insulin resistance, and 8-isoprostane (marker of oxidative stress) were reduced similarly in both groups (main effect of time, P < 0.05 for all comparisons). Visceral fat mass, relative skeletal muscle index (RSMI), blood pressure, LDL cholesterol, HDL cholesterol, triglycerides, fasting glucose, HbA1c, TNF-alpha and IL-6 remained unchanged in both groups by week 8. CONCLUSION: These findings suggest that the weight loss and metabolic benefits of TRF do not differ between premenopausal and postmenopausal women with obesity.

Time-Restricted Eating to Improve Cardiovascular Health.

PURPOSE OF REVIEW: Time-restricted eating (TRE) is a form of intermittent fasting that involves confining the eating window to 4-10 h and fasting for the remaining hours of the day. The purpose of this review is to summarize the current literature pertaining to the effects of TRE on body weight and cardiovascular disease risk factors. RECENT FINDINGS: Human trial findings show that TRE reduces body weight by 1-4% after 1-16 weeks in individuals with obesity, relative to controls with no meal timing restrictions. This weight loss results from unintentional reductions in energy intake (~350-500 kcal/day) that occurs when participants confine their eating windows to 4-10 h/day. TRE is also effective in lowering fat mass, blood pressure, triglyceride levels, and markers of oxidative stress, versus controls. This fasting regimen is safe and produces few adverse events. These findings suggest that TRE is a safe diet therapy that produces mild reductions in body weight and also lowers several key indicators of cardiovascular disease in participants with obesity.

Changes in subjective measures of appetite during 6 months of alternate day fasting with a low carbohydrate diet.

OBJECTIVE: Alternate day fasting (ADF) has been shown to lower body weight and improve subjective appetite by increasing fullness. What remains unknown, however, is whether carbohydrate restriction during ADF would provide additional weight loss benefits by helping to lower hunger as well. Accordingly, this study examined the effect of 6-months of ADF combined with a low carbohydrate diet on fasting and postprandial appetite ratings. METHODS: Adults with obesity (n = 31) participated in ADF (600 kcal "fast day" alternated with an ad libitum "feast day") with a low-carbohydrate background diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period. RESULTS: After 6-months of an ADF-low carbohydrate diet, body weight decreased (P < 0.01) by 6.2 ± 1.0 kg, relative to baseline. Subjective hunger and fullness did not change throughout the study. Fasting insulin decreased (P < 0.05) by 3.3 ± 1.3 µlU/mL by month 6, relative to baseline. Fasting glucose and insulin resistance, remained unchanged over the course of the study. Hunger and fullness were not related to body weight, glucoregulatory factors or energy intake. CONCLUSIONS: These findings suggest that ADF combined with a low carbohydrate diet is not associated with any changes in appetite, relative to baseline. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03528317.

Alternate Day Fasting Combined with a Low Carbohydrate Diet: Effect on Sleep Quality, Duration, Insomnia Severity and Risk of Obstructive Sleep Apnea in Adults with Obesity.

Background: Alternate day fasting combined with a low carbohydrate diet (ADF-LC) is an effective weight loss regimen. Whether the weight loss induced by ADF-LC can improve sleep, remains unknown. Objective: This study examined the effect an ADF-LC diet on sleep quality, duration, insomnia severity and the risk of obstructive sleep apnea. Methods: Adults with obesity (n = 31) participated in ADF (600 kcal "fast day"; ad libitum intake "feast day") with a low-carbohydrate diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period. Results: Reductions in body weight (-5 ± 1 kg, p < 0.001) and fat mass (-4 ± 1 kg, p < 0.01) were noted during the weight loss period, and these reductions were sustained during the weight maintenance period. Lean mass and visceral fat remained unchanged. The Pittsburgh Sleep Quality Index (PSQI) score indicated poor sleep quality at baseline (6.4 ± 0.7) with no change by month 3 or 6, versus baseline. ISI score indicated subthreshold insomnia at baseline (8.5 ± 1.0), with no change by month 3 or 6, versus baseline. The percent of subjects with high risk of obstructive sleep apnea at baseline was 45%, with no change by month 3 or 6. Wake time, bedtime, and sleep duration remained unchanged. Conclusion: The ADF-LC diet does not impact sleep quality, duration, insomnia severity or the risk of obstructive sleep apnea in adults with obesity.

Does the weight loss efficacy of alternate day fasting differ according to sex and menopausal status?

BACKGROUND AND AIMS: This study examined if the weight loss and metabolic benefits of alternate day fasting (ADF) varies according to sex and menopausal status in adults with obesity. METHODS AND RESULTS: This secondary analysis pooled the data of men and women (n = 75) who participated in three 12-week ADF studies (500 kcal fast day; alternated with an ad libitum intake feast day). Body weight decreased in premenopausal women (-4.6 ± 3.2%), postmenopausal women (-6.5 ± 3.2%) and men (-6.2 ± 4.4%) (main effect of time, P < 0.001), with no difference between groups (no group × time interaction). Energy intake on fast days was higher than prescribed in all groups (∼400-500 excess kcal consumed), with no differences between groups. Fat mass, lean mass, fasting insulin, and insulin resistance, and blood pressure decreased similarly in all groups (main effect of time, P < 0.05 for all comparisons). LDL cholesterol decreased more in postmenopausal versus premenopausal women (group × time interaction, P = 0.01). Fasting glucose, HDL cholesterol, and triglycerides remained unchanged in all groups. CONCLUSION: These findings suggest that the weight loss and metabolic benefits of ADF do not generally vary according to sex or menopausal status in adults with obesity. TRIAL REGISTRATION: Clinicaltrials.gov, NCT00960505; NCT03528317.

Effects of 4- and 6-h Time-Restricted Feeding on Weight and Cardiometabolic Health: A Randomized Controlled Trial in Adults with Obesity.

Time-restricted feeding (TRF) regimens have grown in popularity; however, very few studies have examined their weight-loss efficacy. We conducted the first human trial (Clinicaltrials.gov NCT03867773) to compare the effects of two popular forms of TRF (4 and 6 h) on body weight and cardiometabolic risk factors. Adults with obesity were randomized to 4-h TRF (eating only between 3 and 7 p.m.), 6-h TRF (eating only between 1 and 7 p.m.), or a control group (no meal timing restrictions). After 8 weeks, 4- and 6-h TRF produced comparable reductions in body weight (∼3%), insulin resistance, and oxidative stress, versus controls. Energy intake was reduced by ∼550 kcal/day in both TRF groups, without calorie counting. These findings suggest that 4- and 6-h TRF induce mild reductions in body weight over 8 weeks and show promise as interventions for weight loss. These diets may also improve some aspects of cardiometabolic health.

Effect of time restricted feeding on the gut microbiome in adults with obesity: A pilot study.

BACKGROUND: Time restricted feeding is a form of intermittent fasting where participants shorten the daily window in which they eat. AIM: This is the first study to examine the effects of intermittent fasting on changes in the gut microbiome. METHODS: Adults with obesity (n = 14) participated in a daily 8-hour time restricted feeding intervention (8-hour feeding window/16-hour fasting window) for 12 weeks. Fecal microbiota were determined by 16 S rRNA (ribosomal ribonucleic acid) gene sequencing of stool samples. RESULTS: Body weight decreased (P < 0.05) by -2 ± 1 kg. Gut microbiota phylogenetic diversity remained unchanged. The two most common phyla were Firmicutes and Bacteroidetes accounting for 61.2% and 26.9% of total abundance at baseline. No significant alterations in the abundance of Firmicutes, Bacteroidetes, or any other phyla were detected after 12 weeks of time restricted feeding. CONCLUSIONS: Time restricted feeding did not significantly alter the diversity or overall composition of the gut microbiome.

Weight loss efficacy of alternate day fasting versus daily calorie restriction in subjects with subclinical hypothyroidism: a secondary analysis.

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-stimulating hormone remained unchanged. Thus, ADF and CR produce similar weight loss in this population, without affecting thyroid hormone levels. Novelty Intermittent fasting and daily restriction produce similar reductions in body weight in subjects with subclinical hypothyroidism.

Differential Effects of Alternate-Day Fasting Versus Daily Calorie Restriction on Insulin Resistance.

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 study that compared ADF (25% energy needs on "fast days"; 125% energy needs on alternating "feast days") with CR (75% energy needs every day) and a control group regimen. RESULTS: In insulin-resistant participants, weight loss was not different between ADF (-8% ± 2%) and CR (-6% ± 1%) by month 12, relative to controls (P < 0.0001). Fat mass and BMI decreased (P < 0.05) similarly from ADF and CR. ADF produced greater decreases (P < 0.05) in fasting insulin (-52% ± 9%) and insulin resistance (-53% ± 9%) compared with CR (-14% ± 9%; -17% ± 11%) and the control regimen by month 12. Lean mass, visceral fat mass, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, blood pressure, C-reactive protein, tumor necrosis factor α, and interleukin 6 values remained unchanged. CONCLUSIONS: These findings suggest that ADF may produce greater reductions in fasting insulin and insulin resistance compared with CR in insulin-resistant participants despite similar decreases in body weight.

Beverage intake during alternate-day fasting: Relationship to energy intake and body weight.

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 completers) were randomized to one of three groups for 12 months: (a) ADF; (b) CR; or (c) control. RESULTS: At baseline, intakes of diet soda, caffeinated beverages, sugar-sweetened soda, alcohol, juice, and milk were similar between groups. There were no statistically significant changes in the intake of these beverages by month 6 or 12 between ADF (feast or famine day), CR, or control groups. Beverage intake was not related to energy intake or body weight at month 6 or 12 in any group. CONCLUSION: These pilot findings suggest that intermittent fasting does not impact beverage intake in a way that affects energy intake or body weight.

Alternate day fasting combined with a low-carbohydrate diet for weight loss, weight maintenance, and metabolic disease risk reduction.

OBJECTIVE: Alternate day fasting (ADF) is a popular weight loss regimen. Whether carbohydrate restriction can enhance the weight loss achieved with ADF remains unclear. Accordingly, this study examined the effect of ADF combined with a low-carbohydrate diet on body weight and metabolic disease risk factors. METHODS: Adults with obesity (n = 31) participated in ADF (600 kcal "fast day" alternated with an ad libitum "feast day") with a low-carbohydrate background diet (30% carbohydrates, 35% protein, and 35% fat). The 6-month trial consisted of a 3-month weight loss period followed by a 3-month weight maintenance period. RESULTS: Body weight decreased (-5.5 ± 0.5%; P < .001) during the weight loss period (month 0-3) but remained stable (P = .57) during the weight maintenance period (month 4-6). Net weight loss by month 6 was -6.3 ± 1.0%. Fat mass was reduced (P < .01) by month 6, while lean mass and visceral fat mass remained unchanged. Total cholesterol and low-density lipoprotein (LDL) cholesterol levels decreased (P < .05) by -6 ± 2% and - 8 ± 3%, respectively, by month 6. Systolic blood pressure was also reduced (P = .03) by -7 ± 3 mm Hg. Fasting insulin decreased (P = .03) by -24 ± 8% by month 6 relative to baseline. High-density lipoprotein (HDL) cholesterol, triglycerides, diastolic blood pressure, heart rate, fasting glucose, homeostatic model assessment of insulin resistance (HOMA-IR), and haemoglobin A1C (HbA1c) remained unchanged. CONCLUSIONS: These findings suggest that ADF combined with a low-carbohydrate diet is effective for weight loss, weight maintenance, and improving certain metabolic disease risk factors such as LDL cholesterol, blood pressure, and fasting insulin. While these preliminary findings are promising, they still require confirmation by a randomized control trial.