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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., Competing Interests: Declaration of Competing Interest KAV has a consulting relationship with the sponsor of the research, Nestle Health Sciences. The other authors have no conflicts of interest to disclose., (Copyright © 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background/objectives: The winter holiday season in the United States, which spans mid-November to mid-January, contributes to over half of annual body weight gain. Although self-reported data have linked this weight change to both increased energy intake and reduced physical activity, objective techniques have never been used; and thus, the actual cause of holiday weight gain is controversial. Here, we aimed to determine changes in components of energy balance leading to the holiday weight gain., Methods: Body weight change was compared between the pre-holiday (mid-September to mid-November) and the holiday period (mid-November to early January). Total energy expenditure (TEE) was measured using doubly labeled water during holiday time (early to mid-December). Subjective (ratings) and physiological (appetite-regulating hormones) measures of appetite, eating-away-from-home frequency, and incentive salience of food pictures were also evaluated., Results: In 23 obese adults (87% female), body weight change during the holidays (0.41 ± 0.42 kg) was significantly higher (P = 0.02) than the body weight change during the pre-holiday period (-0.86 ± 0.42 kg). TEE was unchanged during the two periods, suggesting no role of energy expenditure on weight gain. However, participants reported lower satisfaction after a meal pre-load which was significantly correlated with increased body weight during the holiday period. An increase in number of episodes of eating at sit-down restaurants was also reported during that period. Overall, these changing behaviors were supported by a non-significant increase in energy intake (+80 kcal/day, P = 0.07) observed during the study holiday period., Conclusion: We conclude that a decrease in energy expenditure does not result in the weight increase, but that increase in food intake is the more likely cause. Our data imply that compromised internal satiety mechanisms in presence of external food cues and diet-related behavioral variables during the holidays may influence weight gain.

Background: Obesity is associated with right ventricular (RV) dysfunction, but its effect on RV remodeling in patients with pulmonary hypertension (PHTN) has not been studied. We evaluated the effect of obesity, and its interplay with diabetes, in patients with PHTN using RV echocardiographic strain imaging., Methods: One hundred eighty-five patients underwent echocardiographic imaging and pulmonary artery pressure was calculated using tricuspid regurgitation jet velocity. From focused RV apical-four-chamber view, global and mid peak systolic RV free wall longitudinal strain (FWLS) was calculated using speckle-tracking software., Results: Global and mid RV FWLS in patients with PHTN (N.=84) was lower (-16.8±7 vs. 18.9±6.3, P=0.035 and -11.2±12.8 vs. -18.9±9.2, P=0.002 respectively) compared with patients without PHTN (N.=101). Among patients without PHTN, obese patients (BMI>30) had lower global and mid RV FWLS (-17.2±6.2 vs. -20.3±5.7, P=0.012 and -17.6±7.2 vs. -21.9±7.3, P=0.004), even after excluding diabetic patients (Mid RV FWLS -18.2±6.8 vs. -22.1±8, P=0.032). Among patients with PHTN, obese patients had similar RV FWLS compared with non-obese patients (P=0.46). However, on excluding diabetic patients from PHTN group, obese patients with PHTN had higher global and mid RV FWLS (-21.7±5.7 vs. -16.1±8, P=0.017 and 23.8±4.8 vs. -17±9.4, P=0.009 respectively) compared to non-obese patients which suggests a protective effect of obesity on RV function in patients with PHTN., Conclusions: Obesity is associated with subclinical RV dysfunction as assessed by RV strain imaging, but paradoxically it may confer a protective effect on RV function once the patient develops PHTN. Future studies should evaluate the clinical impact of this paradox.

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 fasting., Methods: Obese participants ( n = 34) took part in 12 months of ADF and were grouped into a high (≥5%) or low-weight-loss (<5%) group post-treatment., Results: The high-weight-loss group demonstrated increased ( p = 0.04) fullness, decreased ( p = 0.03) hunger, increased dietary protein intake (15% to 20% of kcal, p = 0.04), and better adherence to fast-day calorie goals., Conclusions: Thus, individuals who achieve clinically significant weight loss with ADF demonstrate improved satiety, increased protein intake, and better adherence to fast-day calorie goals.

Purpose: We investigated the associations between frequency of eating at fast-food, fast-casual, all-you-can-eat, and sit-down restaurants and the body mass index (BMI) in non-large metro Wisconsin communities. To inform prevention efforts, we also analyzed the socioeconomic/environmental and nutrition attitudes/behavior variables that may drive the frequent eating away from home., Design: Cross-sectional analysis of an ancillary data set from the Survey of Health of Wisconsin collected between October 2012 and February 2013., Setting: Six Wisconsin counties: 1 classified as rural, 1 as large fringe metro, and 4 as small metro., Subjects: Adults ≥18 years (N = 1418)., Measures: Field staff measured height and weight and administered a survey on the frequency of eating away from home, and socioeconomic and nutritional behavior variables., Analysis: Multivariable regression., Results: The BMI of respondents averaged 29.4 kg/m 2 (39% obese). Every 1-meal/week increase in fast-food and sit-down restaurant consumption was associated with an increase in BMI by 0.8 and 0.6 kg/m 2 , respectively. Unavailability of healthy foods at shopping and eating venues and lack of cooking skills were both positively associated with consumption of fast-food and sit-down meals. Individuals who described their diet as healthy, who avoided high-fat foods, and who believed their diet was keeping their weight controlled did not visit these restaurants frequently., Conclusion: Obesity prevention efforts in non-large metro Wisconsin communities should consider socioeconomic/environmental and nutritional attitudes/behavior of residents when designing restaurant-based or community education interventions.

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 Participants: A single-center randomized clinical trial of obese adults (18 to 64 years of age; mean body mass index, 34) was conducted between October 1, 2011, and January 15, 2015, at an academic institution in Chicago, Illinois., Interventions: Participants were randomized to 1 of 3 groups for 1 year: alternate-day fasting (25% of energy needs on fast days; 125% of energy needs on alternating "feast days"), calorie restriction (75% of energy needs every day), or a no-intervention control. The trial involved a 6-month weight-loss phase followed by a 6-month weight-maintenance phase., Main Outcomes and Measures: The primary outcome was change in body weight. Secondary outcomes were adherence to the dietary intervention and risk indicators for cardiovascular disease., Results: Among the 100 participants (86 women and 14 men; mean [SD] age, 44 [11] years), the dropout rate was highest in the alternate-day fasting group (13 of 34 [38%]), vs the daily calorie restriction group (10 of 35 [29%]) and control group (8 of 31 [26%]). Mean weight loss was similar for participants in the alternate-day fasting group and those in the daily calorie restriction group at month 6 (-6.8% [95% CI, -9.1% to -4.5%] vs -6.8% [95% CI, -9.1% to -4.6%]) and month 12 (-6.0% [95% CI, -8.5% to -3.6%] vs -5.3% [95% CI, -7.6% to -3.0%]) relative to those in the control group. Participants in the alternate-day fasting group ate more than prescribed on fast days, and less than prescribed on feast days, while those in the daily calorie restriction group generally met their prescribed energy goals. There were no significant differences between the intervention groups in blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, insulin resistance, C-reactive protein, or homocysteine concentrations at month 6 or 12. Mean high-density lipoprotein cholesterol levels at month 6 significantly increased among the participants in the alternate-day fasting group (6.2 mg/dL [95% CI, 0.1-12.4 mg/dL]), but not at month 12 (1.0 mg/dL [95% CI, -5.9 to 7.8 mg/dL]), relative to those in the daily calorie restriction group. Mean low-density lipoprotein cholesterol levels were significantly elevated by month 12 among the participants in the alternate-day fasting group (11.5 mg/dL [95% CI, 1.9-21.1 mg/dL]) compared with those in the daily calorie restriction group., Conclusions and Relevance: Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction., Trial Registration: clinicaltrials.gov Identifier: NCT00960505.

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 loss than other races. Baseline body weight and baseline BMI did not predict degree of weight loss achieved with the diet. These findings may help clinicians to decide which population groups may benefit most from an ADF approach., (Copyright © 2015 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

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 and heart disease risk., Methods: Obese subjects (n = 74) were randomized to 1 of 3 groups for 8 weeks: 1) ADF-L: lunch, 2) ADF-D: dinner, or 3) ADF-SM: small meals., Results: Body weight decreased similarly (P < 0.001) in all groups (ADF-L: 3.5 ± 0.4 kg, ADF-D 4.1 ± 0.5 kg, ADF-SM 4.0 ± 0.5 kg). Reductions (P < 0.001) in fat mass and visceral fat were also comparable. Plasma lipids remained unchanged, and low density lipoprotein (LDL) particle size increased (P < 0.05) in all groups (1.3 ± 0.5 Å). Systolic blood pressure decreased (P < 0.05) by ADF-SM only. Fasting glucose, insulin, and HOMA-IR remained unchanged., Conclusions: Thus, allowing individuals to consume the fast day meal at dinner or small meals produces similar weight loss and cardio-protection as consuming the meal at lunch. This flexibility in meal timing may increase tolerability and long-term adherence to ADF protocols., (© 2014 The Obesity Society.)

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), 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 groups, respectively. Fat mass and waist circumference decreased (P < 0.001), while lean mass was retained in the combination group. Low-density lipoprotein (LDL) cholesterol decreased (12 ± 5%, P < 0.05) and high-density lipoprotein (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 groups, 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., (Copyright © 2013 The Obesity Society.)

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.

Background: Obesity is associated with an atherogenic lipid profile characterized by a predominance of small LDL and HDL particles. Weight loss, by dietary restriction or exercise, increases LDL particle size. Whether these interventions can augment HDL size in conjunction with LDL size remains unknown., Objective: This study compared the effects of alternate day fasting (ADF), calorie restriction (CR), and endurance exercise on LDL and HDL particle size in overweight and obese subjects., Methods: In a 12-week parallel-arm trial, adult subjects (n = 60) were randomized to 1 of 4 groups: 1) ADF (75% energy restriction for 24-h alternated with ad libitum feeding for 24-h), 2) CR (25% energy restriction every day), 3) exercise (moderate intensity training 3 x/week), or 4) control., Results: Body weight was reduced (P < 0.001) by ADF, CR, and exercise (5.2 ± 1.1%, 5.0 ± 1.4%, 5.1 ± 0.9%, respectively). Plasma LDL cholesterol decreased (P < 0.05) with ADF (10 ± 4%) and CR (8 ± 4%), whereas HDL cholesterol increased (P < 0.05) with exercise (16 ± 5%). Integrated LDL particle size was augmented (P = 0.01) by ADF and CR. The proportion of small LDL particles decreased (P = 0.04) with ADF only, and the proportion of large HDL particles increased (P = 0.03) with exercise only., Conclusion: These results indicate that dietary restriction increases LDL particle size, while endurance training augments HDL particle size, with minimal weight loss. None of these interventions concomitantly increased both LDL and HDL particle size, however.

Alternate day modified fasting (ADMF) beneficially modulates several indicators of CHD risk, but its effects on LDL particle size have never been tested. Accordingly, we examined the effects of ADMF on LDL particle size and distribution in obese adults. Sixteen obese subjects participated in a 10-week trial with three consecutive phases: (1) 2-week control phase; (2) 4-week ADMF controlled feeding phase; (3) 4-week ADMF self-selected feeding phase. After 8 weeks of diet, body weight and waist circumference were reduced (P < 0·05) by 5·6 (sem 0·9) kg and 4·0 (sem 0·9) cm, respectively. LDL-cholesterol and TAG concentrations decreased (P < 0·05) by 25 (sem 10) % and 32 (sem 6) %, respectively. Peak LDL particle size increased (P < 0·05) from 266 (sem 1) to 268 (sem 1) Å. Additionally, the proportion of small LDL particles decreased (P < 0·05) from 13 (sem 2) % to 9 (sem 3) %, while the proportion of large LDL particles increased (P < 0·05) from 68 (sem 4) % to 76 (sem 4) % post-treatment. These findings suggest that ADMF is an effective diet strategy for increasing LDL particle size and decreasing the proportion of small, dense LDL particles in obese adults.

Background: Low-fat (LF) and high-fat (HF) weight loss diets improve brachial artery flow-mediated dilation (FMD) in obese individuals, although results are conflicting. Moreover, the role that adipose tissue plays in mediating these diet-related effects are unknown., Objective: This study examined how modulations in FMD by HF and LF diets relate to changes in adipocyte parameters., Design: Obese subjects (n = 17) were randomized to a HF diet (60% kcal as fat) or a LF diet (25% kcal as fat) for 6 weeks. Both groups were restricted by 25% of energy needs., Results: Body weight decreased (P <0.05) in both groups (HF: -6.6 ± 0.5 kg, LF: -4.7 ± 0.6 kg). Fat mass and waist circumference were reduced (P <0.05) in the LF group only (-4.4 ± 0.3 kg; -3.6 ± 0.8 cm, respectively). FMD improved (P <0.05) in the LF group (7.4 ± 0.8% to 9.8 ± 0.8; 32% increase) and was impaired in the HF group (8.5 ± 0.6% to 6.9 ± 0.7; 19% reduction). Increases in plasma adiponectin (P <0.05, 16 ± 5%), and decreases in resistin (P <0.05, -26 ± 11%), were shown by the LF diet only. Greater decreases in leptin were observed with LF (-48 ± 9%) versus HF (-28 ± 12%) (P <0.05, diet × time). Increased FMD by the LF diet was associated with increased adiponectin, and decreased fat mass, waist circumference, leptin, and resistin., Conclusion: Beneficial modulations in vascular health by LF diets may be mediated by improvements in adipocyte parameters.

The ability of alternate-day fasting (ADF) to modulate adipocyte parameters in a way that is protective against coronary heart disease (CHD) has yet to be tested. Accordingly, we examined the effects of ADF on adipokine profile, body composition, and CHD risk indicators in obese adults. Sixteen obese subjects (12 women/4 men) participated in a 10-week trial with three consecutive dietary intervention phases: (i) 2-week baseline control phase, (ii) 4-week ADF controlled feeding phase, and (iii) 4-week ADF self-selected feeding phase. After 8 weeks of treatment, body weight and waist circumference were reduced (P < 0.05) by 5.7 ± 0.9 kg, and 4.0 ± 0.9 cm, respectively. Fat mass decreased (P < 0.05) by 5.4 ± 0.8 kg, whereas fat-free mass did not change. Plasma adiponectin was augmented (P < 0.05) by 30% from baseline. Leptin and resistin concentrations were reduced (P < 0.05) by 21 and 23%, respectively, post treatment. Low-density lipoprotein cholesterol (LDL-C) and triacylglycerol concentrations were 25% and 32% lower (P < 0.05), respectively, after 8 weeks of ADF. High-density lipoprotein cholesterol (HDL-C), C-reactive protein, and homocysteine concentrations did not change. Decreases in LDL-C were related to increased adiponectin (r = -0.61, P = 0.01) and reduced waist circumference (r = 0.39, P = 0.04). Lower triacylglycerol concentrations were associated with augmented adiponectin (r = -0.39, P = 0.04) and reduced leptin concentrations (r = 0.45, P = 0.03) post-treatment. These findings suggest that adipose tissue parameters may play an important role in mediating the cardioprotective effects of ADF in obese humans.

Background: Alternate day modified fasting (ADMF) is an effective strategy for weight loss in obese adults., Objective: The objective of this study was to examine the dietary and physical activity adaptations that occur during short-term ADMF, and to determine how these modulations affect rate of weight loss., Methods: Sixteen obese subjects (12 women/4 men) completed a 10-week trial consisting of 3 phases: 1) 2-week control phase, 2) 4-week ADMF controlled feeding phase, and 3) 4-week ADMF self-selected feeding phase., Results: Body weight decreased (P < 0.001) by 5.6 ± 1.0 kg post-treatment. Energy intake on the fast day was 26 ± 3% of baseline needs (501 ± 28 kcal/d). No hyperphagic response occurred on the feed day (95 ± 6% of baseline needs consumed, 1801 ± 226 kcal/d). Daily energy restriction (37 ± 7%) was correlated to rate of weight loss (r = 0.42, P = 0.01). Dietary fat intake decreased (36% to 33% of kcal, P < 0.05) with dietary counseling, and was related to rate of weight loss (r = 0.38, P = 0.03). Hunger on the fast day decreased (P < 0.05) by week 2, and remained low. Habitual physical activity was maintained throughout the study (fast day: 6416 ± 851 steps/d; feed day: 6569 ± 910 steps/d)., Conclusion: These findings indicate that obese subjects quickly adapt to ADMF, and that changes in energy/macronutrient intake, hunger, and maintenance of physical activity play a role in influencing rate of weight loss by ADMF.

Background: The ability of modified alternate-day fasting (ADF; ie, consuming 25% of energy needs on the fast day and ad libitum food intake on the following day) to facilitate weight loss and lower vascular disease risk in obese individuals remains unknown., Objective: This study examined the effects of ADF that is administered under controlled compared with self-implemented conditions on body weight and coronary artery disease (CAD) risk indicators in obese adults., Design: Sixteen obese subjects (12 women, 4 men) completed a 10-wk trial, which consisted of 3 phases: 1) a 2-wk control phase, 2) a 4-wk weight loss/ADF controlled food intake phase, and 3) a 4-wk weight loss/ADF self-selected food intake phase., Results: Dietary adherence remained high throughout the controlled food intake phase (days adherent: 86%) and the self-selected food intake phase (days adherent: 89%). The rate of weight loss remained constant during controlled food intake (0.67 +/- 0.1 kg/wk) and self-selected food intake phases (0.68 +/- 0.1 kg/wk). Body weight decreased (P < 0.001) by 5.6 +/- 1.0 kg (5.8 +/- 1.1%) after 8 wk of diet. Percentage body fat decreased (P < 0.01) from 45 +/- 2% to 42 +/- 2%. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations decreased (P < 0.01) by 21 +/- 4%, 25 +/- 10%, and 32 +/- 6%, respectively, after 8 wk of ADF, whereas HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 +/- 5 to 116 +/- 3 mm Hg., Conclusion: These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CAD risk. This trial was registered at clinicaltrials.gov as UIC-004-2009.

Adipose tissue physiology plays an important role in mediating disease risk. Weight loss in obese individuals improves indicators of adipocyte physiology. However, the minimum degree of weight loss required to elicit improvements remains unknown. The objective of the present study was to determine the minimum weight loss required to improve adipokine profile and decrease fat cell size in severely obese women. Thirteen severely obese women (body mass index, 50 +/- 3 kg/m(2); age, 35 +/- 1 years) consumed a low-calorie diet for 3 weeks with the goal of losing 5% of their initial weight. Subjects were divided into 2 weight loss groups posttreatment: less than 5% weight loss and 5% to 10% weight loss. Body weight was reduced (P < .05) in both groups (-1.4 +/- 1.0 and -6.8 +/- 0.6 kg, respectively). Adiponectin concentrations increased (P < .05) by 20% in the 5% to 10% weight loss group only. Likewise, leptin and resistin decreased (P < .05) by 37% and 27%, respectively, in the group that lost more weight. Visceral and subcutaneous fat cell size was 41% and 37% smaller (P < .01), respectively, in the 5% to 10% weight loss group. Smaller visceral adipocyte size was related to lower insulin (r = 0.82, P = .01) and glucose (r = 0.58, P = .04) concentrations posttreatment. These findings suggest that a minimum weight loss of 5% is required to improve adipokine profile and decrease fat cell size in severely obese women. These changes in adipocyte physiology may be linked to reductions in metabolic disease risk in this population.

Summary: Background: Summer weight gain in children has been reported; however, this is usually based on two time points. Our objective was to investigate monthly variation in weight status. Methods: Cross‐sectional, de‐identified health records including height, weight and demographics, collected between 2007 and 2012 from South Central Wisconsin in 70 531 children age 5–16 years were analysed. The monthly averages in body mass index (BMI) z‐score were analysed cross‐sectionally followed by a paired analysis for a subset with one visit each during school and summer months. Results: BMI z‐scores during the summer months (June–August) were lower than values during the school year (September–May). Of note, there was a rapid decrease in BMI z‐scores from May to June, with June BMI z‐score values being 0.065 units less (95% CI 0.046–0.085) than those in May, little change from June to August and a rapid increase between the August and September BMI z‐scores. Conclusion: The monthly pattern does not fully agree with previous two‐point school‐based studies. Results raise concern that the use of two time point measures of BMIs (early fall and late spring) is suboptimal for evaluation of circannual variation. We suggest that future evaluation of the effect of school‐based or summer interventions utilizes additional measures in those periods so that a seasonal analysis can be performed. [ABSTRACT FROM AUTHOR]