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Racial Differences in Relative Skeletal Muscle Mass Loss During Diet-Induced Weight Loss in Women.
Hunter, GR, Bryan, DR, Borges, JH, David Diggs, M, Carter, SJ
Obesity (Silver Spring, Md.). 2018;(8):1255-1260
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Abstract
OBJECTIVE It is unclear whether there are race-specific differences in the maintenance of skeletal muscle during energy restriction. Changes in relative skeletal muscle index (RSMI; limb lean tissue divided by height squared) were compared following (1) diet alone, (2) diet + aerobic training, or (3) diet + resistance training. METHODS Overweight, sedentary African American (AA; n = 72) and European American (EA; n = 68) women were provided an 800-kcal/d diet to reduce BMI < 25 kg/m2 . Regional fat-free mass was measured with dual-energy x-ray absorptiometry. Steady-state VO2 and heart rate responses during walking were measured. RESULTS AA women had greater RSMI and preserved RSMI during diet alone, while RSMI was significantly reduced among EA women (EA women -3.6% vs. AA women + 1.1%; P < 0.05). Diet + resistance training subjects retained RSMI (EA women + 0.2% vs. AA women + 1.4%; P = 50.05), whereas diet + aerobic training subjects decreased RSMI (EA women -1.4% vs. AA women -1.5%; P < 0.05). Maintenance of RSMI was related to delta walking ease and economy. CONCLUSIONS Compared with AA women, EA women are less muscular and lose more muscle during weight loss without resistance training. During diet-induced weight loss, resistance training preserves skeletal muscle, especially among premenopausal EA women. Maintenance of muscle during weight loss associates with better ease and economy of walking.
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Effects of intermittent and continuous calorie restriction on body weight and metabolism over 50 wk: a randomized controlled trial.
Schübel, R, Nattenmüller, J, Sookthai, D, Nonnenmacher, T, Graf, ME, Riedl, L, Schlett, CL, von Stackelberg, O, Johnson, T, Nabers, D, et al
The American journal of clinical nutrition. 2018;(5):933-945
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Abstract
BACKGROUND Although preliminary evidence suggests that intermittent calorie restriction (ICR) exerts stronger effects on metabolic parameters, which may link obesity and major chronic diseases, compared with continuous calorie restriction (CCR), there is a lack of well-powered intervention studies. OBJECTIVE We conducted a randomized controlled trial to test whether ICR, operationalized as the "5:2 diet," has stronger effects on adipose tissue gene expression, anthropometric and body composition measures, and circulating metabolic biomarkers than CCR and a control regimen. DESIGN One hundred and fifty overweight and obese nonsmokers [body mass index (kg/m2) ≥25 to <40, 50% women], aged 35-65 y, were randomly assigned to an ICR group (5 d without energy restriction and 2 d with 75% energy deficit, net weekly energy deficit ∼20%), a CCR group (daily energy deficit ∼20%), or a control group (no advice to restrict energy) and participated in a 12-wk intervention phase, a 12-wk maintenance phase, and a 26-wk follow-up phase. RESULTS Loge relative weight change over the intervention phase was -7.1% ± 0.7% (mean ± SEM) with ICR, -5.2% ± 0.6% with CCR, and -3.3% ± 0.6% with the control regimen (Poverall < 0.001, PICR vs. CCR = 0.053). Despite slightly greater weight loss with ICR than with CCR, there were no significant differences between the groups in the expression of 82 preselected genes in adipose tissue implicated in pathways linking obesity to chronic diseases. At the final follow-up assessment (week 50), weight loss was -5.2% ± 1.2% with ICR, -4.9% ± 1.1% with CCR, and -1.7% ± 0.8% with the control regimen (Poverall = 0.01, PICR vs. CCR = 0.89). These effects were paralleled by proportional changes in visceral and subcutaneous adipose tissue volumes. There were no significant differences between ICR and CCR regarding various circulating metabolic biomarkers. CONCLUSION Our results on the effects of the "5:2 diet" indicate that ICR may be equivalent but not superior to CCR for weight reduction and prevention of metabolic diseases. This trial was registered at clinicaltrials.gov as NCT02449148.
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Compensatory mechanisms activated with intermittent energy restriction: A randomized control trial.
Coutinho, SR, Halset, EH, Gåsbakk, S, Rehfeld, JF, Kulseng, B, Truby, H, Martins, C
Clinical nutrition (Edinburgh, Scotland). 2018;(3):815-823
Abstract
BACKGROUND & AIMS Strong compensatory responses, with reduced resting metabolic rate (RMR), increased exercise efficiency (ExEff) and appetite, are activated when weight loss (WL) is achieved with continuous energy restriction (CER), which try to restore energy balance. Intermittent energy restriction (IER), where short spells of energy restriction are interspaced by periods of habitual energy intake, may offer some protection in minimizing those responses. We aimed to compare the effect of IER versus CER on body composition and the compensatory responses induced by WL. METHODS 35 adults (age: 39 ± 9 y) with obesity (BMI: 36 ± 4 kg/m2) were randomized to lose a similar weight with an IER (N = 18) or a CER (N = 17) diet over a 12 week period. Macronutrient composition and overall energy restriction (33% reduction) were similar between groups. Body weight/composition, RMR, fasting respiratory quotient (RQ), ExEff (10, 25, and 50 W), subjective appetite ratings (hunger, fullness, desire to eat, and prospective food consumption (PFC)), and appetite-regulating hormones (active ghrelin (AG), cholecystokinin (CCK), total peptide YY (PYY), active glucagon-like peptide-1 (GLP-1), and insulin) were measured before and after WL. RESULTS Changes in body weight (≈12.5% WL) and composition were similar in both groups. Fasting RQ and ExEff at 10 W increased in both groups. Losing weight, either by IER or CER dieting, did not induce significant changes in subjective appetite ratings. RMR decreased and ExEff at 25 and 50 W increased (P < 0.001 for all) in IER group only. Basal and postprandial AG increased (P < 0.05) in IER group, whereas basal active GLP-1 decreased (P = 0.033) in CER group only. Postprandial CCK decreased in both groups (P = 0.0012 and P = 0.009 for IER and CER groups, respectively). No between group differences were apparent for any of the outcomes. CONCLUSIONS The technique used to achieve energy restriction, whether it is continuous or intermittent, does not appear to modulate the compensatory mechanisms activated by weight loss. CLINICAL TRIAL REGISTRATION NUMBER NCT02169778 (the study was registered in clinicaltrial.gov).
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Low glycaemic index diet is effective in managing weight among obese postpartum women.
Basharat, S, Gilani, SA, Burq, AI, Bashir, S
JPMA. The Journal of the Pakistan Medical Association. 2018;(4):548-553
Abstract
OBJECTIVE To determine the effect of low glycaemic index diet on weight loss among obese post-partum women.. METHODS This randomised controlled trial study was conducted at the National Hospital and Medical Centre, and Services Hospital, Lahore, from April to June 2015, and comprised obese post-partum women. Subjects in the intervention group were assigned low glycaemic index diet for 12 weeks while the control group was advised to continue routine diet. SPSS 22 was used for data analysis. RESULTS Of the 74 participants, 38(51.4%) were in the interventional group and 36(48.6%) in the control group. The low glycaemic index diet had a significant effect on weight reduction in the intervention group compared to the control group (83.6±0.75 vs. 89.1±2) (p=0.02). Low glycaemic diet also had a positive impact on body mass index (p=0.02), body fat percentage (p=0.03) and fat mass (p=0.02). Significant changes were found in the intervention group after 12 weeks in terms of body mass index, body fat percentage, and fat mass, fat-free mass and muscle mass. On the other hand, no changes were established in the control group after 12 weeks of the study period.. CONCLUSIONS Low glycaemic index diet was effective for reducing weight among obese post-partum women.
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Effects of Two Preoperatory Weight Loss Diets on Hepatic Volume, Metabolic Parameters, and Surgical Complications in Morbid Obese Bariatric Surgery Candidates: a Randomized Clinical Trial.
Gils Contreras, A, Bonada Sanjaume, A, Montero Jaime, M, Rabassa Soler, A, Sabench Pereferrer, F, Molina López, A, Becerra Tomás, N, Del Castillo Déjardin, D, Salas-Salvadó, J
Obesity surgery. 2018;(12):3756-3768
Abstract
OBJECTIVE To assess which type of preoperative dietary strategy is most effective in reducing liver volume and assessing its influence on different biochemical parameters and on surgical complications in individuals undergoing bariatric surgery. METHODS Parallel randomized trial comparing the effect of a very low calorie diet (VLCD) and a low calorie diet (LCD) for a period of 21 days before surgery on hepatic volume, anthropometric and biochemical parameters. Compliance and tolerance to the diets, surgical complications, and hospital stay were also determined. RESULTS Eighty-six morbid obese participants undergoing bariatric surgery were randomized. The hepatic volume was significantly reduced in both intervention groups, but no differences in changes between groups were detected. The reduction in the hepatic volume was higher in those patients with a baseline hepatic volume > 3 L compared to those with < 3 L (adjusted P value < 0.001). The percentages of total weight lost were 5.8 and 4.2% (adjusted P value = 0.004) for participants on the VLCD and LCD, respectively. There were no differences between groups for any of the biochemical parameters analyzed, nor in the number of surgical complications nor the length of hospital stay. Adherence to the diet was good; nevertheless, participants in the VLCD intervention showed worse tolerance. CONCLUSIONS In subjects with morbid obesity undergoing bariatric surgery, compared to a LCD, a preoperative 21-day intervention with VLCD is more effective in terms of reducing total body weight but not in terms of reducing the liver volume. Both types of preoperative diets have similar effects on clinical biochemical parameters, rate of surgical complications, and hospital length stay.
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Application of Machine Learning to Predict Dietary Lapses During Weight Loss.
Goldstein, SP, Zhang, F, Thomas, JG, Butryn, ML, Herbert, JD, Forman, EM
Journal of diabetes science and technology. 2018;(5):1045-1052
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BACKGROUND Individuals who adhere to dietary guidelines provided during weight loss interventions tend to be more successful with weight control. Any deviation from dietary guidelines can be referred to as a "lapse." There is a growing body of research showing that lapses are predictable using a variety of physiological, environmental, and psychological indicators. With recent technological advancements, it may be possible to assess these triggers and predict dietary lapses in real time. The current study sought to use machine learning techniques to predict lapses and evaluate the utility of combining both group- and individual-level data to enhance lapse prediction. METHODS The current study trained and tested a machine learning algorithm capable of predicting dietary lapses from a behavioral weight loss program among adults with overweight/obesity (n = 12). Participants were asked to follow a weight control diet for 6 weeks and complete ecological momentary assessment (EMA; repeated brief surveys delivered via smartphone) regarding dietary lapses and relevant triggers. RESULTS WEKA decision trees were used to predict lapses with an accuracy of 0.72 for the group of participants. However, generalization of the group algorithm to each individual was poor, and as such, group- and individual-level data were combined to improve prediction. The findings suggest that 4 weeks of individual data collection is recommended to attain optimal model performance. CONCLUSIONS The predictive algorithm could be utilized to provide in-the-moment interventions to prevent dietary lapses and therefore enhance weight losses. Furthermore, methods in the current study could be translated to other types of health behavior lapses.
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A nonrestrictive, weight loss diet focused on fiber and lean protein increase.
Zhang, L, Pagoto, S, Olendzki, B, Persuitte, G, Churchill, L, Oleski, J, Ma, Y
Nutrition (Burbank, Los Angeles County, Calif.). 2018;:12-18
Abstract
OBJECTIVE We examined the feasibility and acceptability of a non-restrictive diet that was focused on increasing dietary fiber and lean protein intake for weight loss. METHODS Dietary intake was assessed using three randomly selected 24-h dietary recalls. Fifteen obese adults enrolled in a 12-wk study that included six biweekly individual dietary counseling sessions to attain a daily goal of higher fiber (35 g/d) and lean protein (0.8 g/kg/d of individual's ideal body weight) intake. Feasibility was determined by retention and attendance and dietary adherence was measured. RESULTS One participant dropped out of the study before the 12-wk assessment visit. Fourteen participants completed all six counseling sessions and one participant completed five sessions. At week 12, 93% of participants approved of the diet and 92% of participants did not feel hungry while on the diet. Mean fiber intake increased by 6.8 g/d (95% confidence interval [CI], 3.2 to 10.5 g/d) and total protein intake increased by 5.7 g/d (95% CI, -3.7 to 15.0 g/d). The mean change in energy intake was -265.5 kcal/d (95% CI, -454.8 to -76.2 kcal/d). The dietary quality score as measured by the Alternative Healthy Eating Index increased by 6.1 (95% CI, 1.5 to 10.7). The mean change in weight was -2.2% (95% CI, -3.6 to -0.7%). CONCLUSIONS A diet that promotes increased fiber and lean protein intake demonstrates feasibility and high acceptability ratings, which resulted in calorie and weight reductions and an improvement of the dietary quality.
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A review and critique of published real-world weight management program studies.
Primack, C
Postgraduate medicine. 2018;(6):548-560
Abstract
BACKGROUND Beyond the essential but somewhat artificial conditions that typify formal clinical studies, real-world evidence (RWE) of weight loss program effectiveness is paramount for an accurate assessment of such programs and refinement of best practices. OBJECTIVES To evaluate the current state of RWE studies and publications on weight loss, identify the range of weight loss components being used in RWE programs, and to provide a general overview of the consistency or lack of consistency with regard to measuring and reporting outcomes. METHODS A structured search of PubMed was performed to identify relevant English-language publications from 2006 to December 2017 that reported real-world studies of weight loss among adults. Duplicates, non-relevant publications, articles on weight loss surgery, pediatric studies, randomized controlled trials, studies with self-reported weight loss, no objective weight measures, or that failed to include weight loss results were excluded. RESULTS This review included 62 RWE publications. Forty-nine studies included dietary intervention, 37 included exercise, 29 included motivational counseling, and 5 contained some patients who had pharmacologic treatment as part of their weight loss regimen. The numbers of participants per study ranged from 10 to more than 3 million. The interventions reported in the publications included diet, exercise, counseling to promote diet and/or exercise, motivational counseling, and pharmacotherapy, and various combinations of these. CONCLUSIONS Despite general acceptance that weight loss programs are capable of facilitating successful outcomes, this review revealed substantial inconsistency in the design and reporting of such programs, making it very difficult to draw conclusions about the comparative merits of different real-world weight loss strategies/components. In addition, there was a marked lack of congruence with current weight loss management guidelines, and notably few studies incorporating anti-obesity medications. There clearly is a need for greater rigor and standardization among designing and reporting RWE weight-loss studies.
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Weight management in adults with intellectual and developmental disabilities: A randomized controlled trial of two dietary approaches.
Ptomey, LT, Saunders, RR, Saunders, M, Washburn, RA, Mayo, MS, Sullivan, DK, Gibson, CA, Goetz, JR, Honas, JJ, Willis, EA, et al
Journal of applied research in intellectual disabilities : JARID. 2018;:82-96
Abstract
BACKGROUND The prevalence of obesity among individuals with intellectual and developmental disabilities (IDD) is equal to or greater than the general population. METHODS Overweight/obese adults (BMI ≥25 kg/m2 ) with mild-to-moderate intellectual and developmental disabilities were randomized to an enhanced stop light diet (eSLD = SLD + portion-controlled meals, n = 78) or a conventional diet (CD, n = 72) for an 18 months trial (6 months weight loss, 12 months maintenance). Participants were asked to increase physical activity (150 min/week), self-monitor diet and physical activity and attend counselling/educational sessions during monthly home visits. RESULTS Weight loss (6 months) was significantly greater in the eSLD (-7.0% ± 5.0%) compared with the CD group (-3.8% ± 5.1%, p < .001). However, at 18 months, weight loss between groups did not differ significantly (eSLD = -6.7% ± 8.3%; CD = 6.4% ± 8.6%; p = .82). CONCLUSION The eSLD and CD provided clinically meaningful weight loss over 18 months in adults with intellectual and developmental disabilities.
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Effects of alternate-day fasting or daily calorie restriction on body composition, fat distribution, and circulating adipokines: Secondary analysis of a randomized controlled trial.
Trepanowski, JF, Kroeger, CM, Barnosky, A, Klempel, M, Bhutani, S, Hoddy, KK, Rood, J, Ravussin, E, Varady, KA
Clinical nutrition (Edinburgh, Scotland). 2018;(6 Pt A):1871-1878
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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 changes in the VAT:SAT ratio, FFM:total mass ratio, and the adipokine profile between ADF and CR. METHODS Overweight and obese participants (n = 100) were randomized to 1) ADF (alternating every 24-h between consuming 25% or 125% of energy needs); 2) CR (consuming 75% of needs every day); or 3) control (consuming 100% of needs every day) for 24 wk. RESULTS The VAT:SAT ratio did not change in any group. The FFM:total mass ratio increased in both ADF (0.03 ± 0.00) and CR (0.03 ± 0.01) compared to the control group (P < 0.01), with no differences between the intervention groups. Circulating leptin decreased in both the ADF group (-18 ± 6%) and CR group (-31 ± 10%) relative to the control group (P < 0.05), with no differences between the intervention groups. Circulating levels of adiponectin, resistin, IL-6, and TNF-α did not change in either intervention group relative to the control group. CONCLUSION ADF and CR similarly improve the FFM:total mass ratio and reduce leptin after a 24-wk intervention. TRIAL REGISTRATION Clinicaltrials.gov, number NCT00960505.