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Effect of a Personalized Diet to Reduce Postprandial Glycemic Response vs a Low-fat Diet on Weight Loss in Adults With Abnormal Glucose Metabolism and Obesity: A Randomized Clinical Trial.
Popp, CJ, Hu, L, Kharmats, AY, Curran, M, Berube, L, Wang, C, Pompeii, ML, Illiano, P, St-Jules, DE, Mottern, M, et al
JAMA network open. 2022;5(9):e2233760
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Postprandial glycaemic response (PPGR) to foods can be different from person to person. This could be the reason why people experience different weight loss outcomes with standardised diets such as a low glycaemic index diet, low-fat diet or a low carbohydrate diet. In this single-centre, population-based, randomised, blinded clinical trial, 204 participants with irregular glucose metabolism and obesity were randomised to consume either a low-fat or personalised diet for six months in combination with fourteen behavioural change counselling sessions. The participants in the personalised diet group received a colour-coded meal score to indicate their estimated PPGR for different foods. The results of this study showed no significant weight reduction in the personalised diet group compared to the low-fat diet. Further robust studies are required to develop appropriate precision nutrition interventions for weight loss and energy balance. However, healthcare professionals can use the results of this study to understand that both a low-fat diet and a personalised diet, coupled with behavioural counselling, may be effective in promoting weight loss in obese populations with irregular glucose metabolism.
Abstract
IMPORTANCE Interindividual variability in postprandial glycemic response (PPGR) to the same foods may explain why low glycemic index or load and low-carbohydrate diet interventions have mixed weight loss outcomes. A precision nutrition approach that estimates personalized PPGR to specific foods may be more efficacious for weight loss. OBJECTIVE To compare a standardized low-fat vs a personalized diet regarding percentage of weight loss in adults with abnormal glucose metabolism and obesity. DESIGN, SETTING, AND PARTICIPANTS The Personal Diet Study was a single-center, population-based, 6-month randomized clinical trial with measurements at baseline (0 months) and 3 and 6 months conducted from February 12, 2018, to October 28, 2021. A total of 269 adults aged 18 to 80 years with a body mass index (calculated as weight in kilograms divided by height in meters squared) ranging from 27 to 50 and a hemoglobin A1c level ranging from 5.7% to 8.0% were recruited. Individuals were excluded if receiving medications other than metformin or with evidence of kidney disease, assessed as an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration equation, to avoid recruiting patients with advanced type 2 diabetes. INTERVENTIONS Participants were randomized to either a low-fat diet (<25% of energy intake; standardized group) or a personalized diet that estimates PPGR to foods using a machine learning algorithm (personalized group). Participants in both groups received a total of 14 behavioral counseling sessions and self-monitored dietary intake. In addition, the participants in the personalized group received color-coded meal scores on estimated PPGR delivered via a mobile app. MAIN OUTCOMES AND MEASURES The primary outcome was the percentage of weight loss from baseline to 6 months. Secondary outcomes included changes in body composition (fat mass, fat-free mass, and percentage of body weight), resting energy expenditure, and adaptive thermogenesis. Data were collected at baseline and 3 and 6 months. Analysis was based on intention to treat using linear mixed modeling. RESULTS Of a total of 204 adults randomized, 199 (102 in the personalized group vs 97 in the standardized group) contributed data (mean [SD] age, 58 [11] years; 133 women [66.8%]; mean [SD] body mass index, 33.9 [4.8]). Weight change at 6 months was -4.31% (95% CI, -5.37% to -3.24%) for the standardized group and -3.26% (95% CI, -4.25% to -2.26%) for the personalized group, which was not significantly different (difference between groups, 1.05% [95% CI, -0.40% to 2.50%]; P = .16). There were no between-group differences in body composition and adaptive thermogenesis; however, the change in resting energy expenditure was significantly greater in the standardized group from 0 to 6 months (difference between groups, 92.3 [95% CI, 0.9-183.8] kcal/d; P = .05). CONCLUSIONS AND RELEVANCE A personalized diet targeting a reduction in PPGR did not result in greater weight loss compared with a low-fat diet at 6 months. Future studies should assess methods of increasing dietary self-monitoring adherence and intervention exposure. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03336411.
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Referral to Slimming World in UK Stop Smoking Services (SWISSS) versus stop smoking support alone on body weight in quitters: results of a randomised controlled trial.
Lycett, D, Aveyard, P, Farmer, A, Lewis, A, Munafò, M
BMJ open. 2020;10(1):e032271
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Weight gain is a well-known consequence of smoking cessation. The aim of this study was to compare standard stop smoking behavioural support with an intervention that, in addition to providing standard stop smoking support, included personalised weight management support, provided by Slimming World. This study is a parallel group, individually randomised controlled trial. Participants were randomised (1:1) to usual care or Slimming World with usual care. Stop smoking advisors were unaware of the randomisation sequence. Results showed that referral to the Slimming World programme plus usual stop smoking support achieved significantly less weight gain than usual stop smoking support alone. Furthermore, percentage quit was no worse in the treatment than the control group. Authors conclude that referral to a behavioural weight loss programme may be a pragmatic option within stop smoking clinics.
Abstract
INTRODUCTION Most people who stop smoking gain weight. Dietary modification may seem an obvious solution, but food restriction may increase cigarette craving and smoking relapse. TRIAL DESIGN An unblinded parallel randomised controlled trial. METHODS Participants were adult smokers with a body mass index greater or equal to 23 kg/m2. Setting was National Health Service commissioned Stop Smoking Services, interventions were referral to a commercial weight management programme, plus stop smoking support (treatment group), compared with stop smoking support alone (control group). Objective was to compare weight change between interventions in smoking abstainers and not abstinent rates in all. Primary outcome was change in weight (kg) at 12 weeks. Randomisation sequence was computer generated and concealed until allocation. RESULTS Seventy-six participants were recruited, 37 were randomised to the treatment group and 39 to the control group. Change in weight was analysed in long-term abstainers (13 treatment, 14 control) only because the aim was to prevent weight gain associated with smoking cessation. Abstinence was analysed on an intention-to-treat basis (37 treatment, 39 control). At 12 weeks weight gain was less in the treatment than the control group with an adjusted mean difference of -2.3 kg 95% CI (-4.4 to -0.1). Craving scores were lower (Mood and Physical Symptoms Scale craving domain -1.6 (-2.7 to -0.5)) and quit rates were higher in the treatment than the control group (32% vs 21%), although the trial was not powered to superiority in cravings and quit rates. No adverse events or side effects were reported. CONCLUSION In people who are obese and want to quit smoking, these data provide modest encouragement that providing weight management at the time of quitting may be helpful. Those who are not obese, but who are informed about potential weight gain during their quit attempt, were uninterested in a weight management programme. TRIAL REGISTRATION NUMBER ISRCTN65705512.
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Changes in Eating Behaviors of Children with Obesity in Response to Carbohydrate-Modified and Portion-Controlled Diets.
Kirk, S, Woo, JG, Brehm, B, Daniels, SR, Saelens, BE
Childhood obesity (Print). 2017;13(5):377-383
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Paediatric obesity has been shown to be managed most effectively when interventions with multiple components, such as dietary changes, physical activity, supportive parental involvement, and behavioural strategies are included. The aim to the study was to evaluate whether baseline or changes in psychological dimensions of eating behaviours could account for variability in weight status outcomes. For this study, children aged between 7 – 12 years with a fasting blood glucose level of ≤100mg/dl and with a BMI z-score of 1.60 – 2.65 were recruited. The participants were randomly assigned to one of the three diet groups (low carbohydrate, reduced glycaemic load or portion-controlled diet). The study results show that eating behaviours improved significantly with all diets, and increased cognitive restraint and decreased hunger were sustained at 12 months. Disinhibition also remained significantly lower at 12 months for the reduced glycaemic load group. Authors conclude that targeting diets to youth with obesity who have specific characteristics such as sex, race, and/or lower baseline hunger or higher baseline cognitive restraint scores may lead to better outcomes.
Abstract
OBJECTIVE This study's objective was to determine whether two distinct carbohydrate (CHO)-modified diets and a standard portion-controlled (PC) diet differentially impacted children's eating behaviors and whether eating behavior scores predicted lower BMI among children with obesity. METHODS Children (n = 102) aged 7-12 years with obesity were randomly assigned to a 12-month intervention of a low-carbohydrate (LC), reduced glycemic load (RGL), or standard PC diet. The Three-Factor Eating Questionnaire (TFEQ) was completed at baseline, 3, 6, and 12 months by parents to characterize their child's hunger (H), disinhibition (D), and cognitive restraint (CR). Baseline and follow-up TFEQ scores by diet were evaluated relative to BMI status over time. RESULTS All diet groups showed increased CR and decreased H and D from baseline to 3 months, with differences from baseline remaining at 12 months for CR and H. Lower BMI status during study follow-up was associated with different TFEQ scores by diet group (LC and RGL: higher CR; PC: lower H), adjusting for sex, age, and race. Higher CR at follow-up was predicted by race and higher baseline CR; only lower H at baseline predicted lower H at follow-up. CONCLUSION Eating behaviors improved significantly with all diets during the initial 3 months; higher CR and lower H were sustained at treatment's end. BMI outcomes were associated with different eating behaviors in CHO-modified diet groups compared with PC diets. Targeting diets of children with obesity with specific baseline characteristics may lead to improved outcomes.