Search

Aim: We studied the accuracy of bioelectrical impedance analysis (BIA) to assess changes in body composition during moderate weight loss in obese subjects., Methods: Estimates of changes in fat mass (FM) and fat-free mass (FFM) by BIA were compared with those by dual-energy X-ray absorptiometry (DXA) as the reference method during a 10-week standardized weight-loss intervention. In obese women (age: 20-50 years, mean BMI: 33.8 kg/m(2)) participating in a European multicentre trial (nutrient-gene interactions in human obesity [NUGENOB]), body composition was assessed by BIA (Bodystat QuadScan 4000) and DXA (Lunar DPX-IQ at two centres, Hologic QDR 2000 at another centre) at baseline (n=131) and at week 10 (n=105) after a mean weight loss of -5.7 kg., Results: At baseline, BIA significantly overestimated FFM and underestimated FM (by 1-3 kg on average) compared with DXA, and the limits of agreement were wide (mean ± 7-8.5 kg). For body-composition changes, although biases were generally non-significant, the limits of agreement were also wide (mean ± 3.7-4.6 kg). An FFM prediction equation for BIA data was developed in subjects scanned with Lunar instruments and cross-validated in an independent sample of 31 obese women undergoing similar weight loss. However, no major improvement in limits of agreement was found., Conclusion: During moderate diet-induced weight loss, the use of BIA leads to estimates of changes in body composition at the individual level that can differ substantially from those assessed by DXA, indicating that BIA and DXA cannot be used interchangeably. However, BIA in this context may be used for assessing changes in body composition at group level., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Physical activity is a cornerstone in the medical management of obesity and could be important for weight loss following bariatric surgery. This review aims to describe the evolution of physical activity following massive weight loss induced by bariatric surgery, and to identify the relationship between physical activity and amount of weight loss. A literature search identified 20 publications (19 studies) reporting physical activity data in relation to bariatric surgery. All studies were observational. Self-assessment of physical activity was used in all the studies. Objective measures (pedometry) were used in two studies. The time frame for physical activity assessment varied: before surgery in two publications, after surgery in nine, and longitudinal pre- to post-operative evolution in nine. The latter nine publications found an increase in physical activity after bariatric surgery. In 10/13 studies where it was described, there was a positive relationship between physical activity level and amount of weight loss. In conclusion, observational evidence of self-reported physical activity suggests that physical activity increases after bariatric surgery and that physical activity is associated with surgically induced weight loss. However, these findings warrant further evaluation using objective measures of physical activity and testing in controlled trials., (© 2010 The Authors. obesity reviews © 2010 International Association for the Study of Obesity.)

Aim: Adiponectin increases insulin sensitivity, protects arterial walls against atherosclerosis, and regulates glucose metabolism, and is decreased in obese, insulin resistant, and type 2 diabetic patients. Adiponectin circulates in plasma as high, medium, and low molecular weight forms (HMW, MMW, and LMW). The HMW form was suggested to be closely associated with insulin sensitivity. This study investigated whether diet-induced changes in insulin sensitivity were associated with changes in adiponectin multimeric complexes., Subjects: Twenty obese women with highest and twenty obese women with lowest diet induced changes in insulin sensitivity (responders and non-responders respectively), matched for weight loss (body mass index (BMI)=34.5 (s.d. 2.9) resp. 36.5 kg/m(2) (s.d. 4.0) for responders and non-responders), were selected from 292 women who underwent a 10-week low-caloric diet (LCD; 600 kcal/d less than energy requirements). Plasma HMW, MMW, and LMW forms of adiponectin were quantified using Western blot method., Results: LCD induced comparable weight reduction in responders and non-responders by 8.2 and 7.6 kg. Homeostasis model assessment insulin resistance index decreased by 48.1% in responders and remained unchanged in non-responders. Total plasma adiponectin and the quantity of HMW and MMW remained unchanged in both groups, while LMW increased by 16.3% in non-responders. No differences between both groups were observed at baseline and after the study. Total plasma adiponectin, MMW, and LMW were negatively associated with fasting insulin levels at baseline., Conclusion: No differences in total plasma adiponectin, HMW, MMW, and LMW forms were observed between responders and non-responders following 10-week LCD, suggesting that adiponectin is not a major determinant of weight loss-induced improvements in insulin sensitivity.

Objective: To investigate relationships between changes in weight and changes in cardiovascular risk factors in adults, taking intentionality of weight loss into account., Design: Longitudinal study in middle-aged French subjects from the SU.VI.MAX cohort., Subjects: A total of 1773 men (body mass index (BMI) 25.4+/-3.1 kg/m(2), mean+/-s.d) and 2316 women (BMI 23.3+/-3.8 kg/m(2)) aged 45 y and over at baseline., Measurements: Weight, height, blood pressure, serum total cholesterol and fasting blood glucose were measured at baseline and after a 2 y follow-up. Self-reported dieting in order to lose weight, smoking status, leisure-time physical activity, health events and current treatments were assessed through questionnaires., Results: In multivariate analyses, weight change was positively associated with changes in systolic and diastolic blood pressure (P=0.0002 in women, P=0.0001 in men) and with changes in serum total cholesterol (P=0.008 in women, P=0.02 in men), after adjustment for age, baseline level of each cardiovascular risk factor and current treatments. For example, in men, a weight loss of 5 kg was associated with a decrease of 2.5 mmHg in systolic blood pressure and of 1.5 mmHg in diastolic blood pressure. Taking into account self-reported dieting did not modify these associations., Conclusions: In both genders, systolic and diastolic blood pressure and serum cholesterol increased with weight gain and decreased with weight loss, independently of the intentionality to lose weight. At the population level, modest weight loss may have a substantial impact on cardiovascular risk, and preventing even modest weight gain in adults is an important goal in terms of public health.

Background There is evidence that obesity is associated with impairments in executive functions, such as deficits in decision-making, planning or problem solving, which might interfere with weight loss in obese individuals. We performed a systematic review and meta-analysis of decision-making abilities, as measured with the Iowa gambling task (IGT), in obesity without eating disorders. Methods A systematic search was conducted to identify studies comparing IGT performances between groups of obese patients without eating disorders and groups of healthy control groups. The standardized mean differences were calculated for the total IGT scores and for the course of IGT scores. Meta-regression analyses were performed to explore the influence of clinical variables on standardized mean differences. Results Total IGT scores were significantly lower in obese patients compared with normal-weight healthy controls. IGT performances did not differ between groups for the first trials of the task. Significant effect sizes for the last trials of the task were subjected to a high degree of heterogeneity. Conclusion Risky decision-making is impaired in obesity. The clinical importance of non-food-related decision-making impairments remains to be assessed especially in terms of consequences in daily life or the achievement of weight loss. This meta-analysis has been registered in the Prospero database (CRD42016037533). [ABSTRACT FROM AUTHOR]

Background:The A risk allele of rs9939609 of the fat mass- and obesity-associated gene (FTO) increases body fat mass.Objective:To examine whether FTO rs9939609 affects obese individuals' response to a high-fat, low-carbohydrate (CHO) (HF) or low-fat, high-CHO (LF), hypo-energetic diet and whether the effect of the FTO variant depends on dietary fat and CHO content.Design:In a 10-week, European, multi-centre dietary intervention study 771 obese women and men were randomized to either LF (20–25% of energy (%E) from fat, 60–65%E from CHO) or HF (40–45%E from fat, 40–45%E from CHO), hypo-energetic diet (measured resting metabolic rate multiplied by 1.3–600 kcal day−1). Body weight, fat mass (FM), fat-free mass (FFM), waist circumference (WC), resting energy expenditure (REE), fasting fat oxidation as % of REE (FatOx), insulin release (HOMA-β) and a surrogate measure of insulin resistance (HOMA-IR) were measured at baseline and after the intervention. In all, 764 individuals were genotyped for FTO rs9939609.Results:For A-allele carriers the drop-out rate was higher on HF than LF diet (in AT, P=0.002; in AT/AA combined, P=0.003). Among those individuals completing the intervention, we found no effect of FTO rs9939609 genotype on Δweight, ΔFM, ΔFFM, ΔWC or ΔFatOx. However, participants with TT had a smaller reduction in REE on LF than on HF diet (75 kcal/24 h; interaction: P=0.0055). These individuals also showed the greatest reduction in HOMA-β and HOMA-IR (interaction: P=0.0083 and P=0.047).Conclusion:The FTO rs9939609 may interact with the macronutrient composition in weight loss diets in various ways; carriers of the A allele on LF diet appear to have a lower risk for drop out, and TT individuals have a smaller decrease in REE and greater decrease in HOMA-β and HOMA-IR on LF than on HF diet. [ABSTRACT FROM AUTHOR]

Low glycaemic index (GI) diets may facilitate weight loss via behavioural and/or endocrine mechanisms. This study investigated whether the outcomes of the Weight Watchers POINTS® Weight-Loss System could be improved by encouraging dieters to select low GI, high-carbohydrate foods. Ninety-six women (age 20–72 years; BMI 25–40 kg/m2) were recruited as they started the Weight Watchers POINTS® programme for 12 weeks. Weekly classes were randomized so that seven (forty-five women) followed the regular programme while seven others (fifty-one women) followed a revised programme encouraging the selection of low GI foods. Anthropometric and biochemical parameters were measured before and after the 12-week diets. Participants rated hunger and desire to eat using visual analogue scales on 1 d per week, several times per d. Attrition was the same in both groups (32 v. 30 %), as well as many benefits (5 % weight loss, decreases in insulinaemia and blood lipids, waist and hip circumferences, blood pressure). Hunger and desire to eat were rated consistently lower in the low GI group over the 12-week diet. Group differences in subjective sensations were especially large in the afternoon. The 12-week weight management yielded many significant anthropometric and biochemical benefits that were not improved by encouraging dieters to select low GI foods. The subjective benefits (lower hunger and desire to eat) of the low GI diet may be a worthwhile contribution to the motivation of dieters that might affect adherence to the diet over the long term. [ABSTRACT FROM PUBLISHER]

Le régime cétogène, utilisé en thérapeutique dans les épilepsies réfractaires, est un régime hypocalorique, pauvre en glucides, riche en graisses, normo-protidique, induisant une cétose. Son utilisation s'est répandue dans le public, car il permet d'obtenir une perte de poids rapide. La cétose, induite par ce régime, peut évoluer, dans certains cas, vers une acidocétose, par exemple au cours d'une maladie aiguë ou dans des contextes spécifiques d'augmentation des besoins ou de la dépense énergétiques tels que l'allaitement ou une activité physique d'intensité élevée. Nous rapportons le cas d'une femme âgée de 36 ans, n'ayant pas de diabète, ayant développé à six semaines post-partum une acidose métabolique sévère. Cette patiente, alors qu'elle allaitait de façon exclusive, avait repris une activité physique intensive et suivait un régime cétogne depuis dix jours. Une perfusion de sérum salé puis glucosé et une réalimentation progressive diversifiée ont permis une normalisation rapide de son équilibre acido-basique et de sa symptomatologie digestive. Le diagnostic d'acidocétose de lactation doit être suspecté en cas d'acidose métabolique sévère chez des jeunes femmes non-diabétiques en période d'allaitement, ayant eu recours à un régime cétogène. Ketogenic diet, used in therapeutics in refractory epilepsies, is in general a low-calorie diet, with low-carbohydrate, high-fat and adequate protein intake, inducing ketosis. It use has spread to the general population because it helps achieve rapid weight loss. Ketosis induced by this diet may in some cases progress to ketoacidosis, for example during acute illness or in specific settings where energy expenditure is increased such as breastfeeding or high intensity physical activity. We report the case of a 36-years-old lactating woman without diabetes who developed at six weeks postpartum severe metabolic acidosis. This patient, while breastfeeding exclusively, had resumed intensive physical activity and had been on a ketogenic diet for ten days. A filling with salty then glucose serum and a diversified progressive replenishment allowed a rapid normalization of acid-base balance and digestive symptomatology. The diagnosis of lactation ketoacidosis should be suspected in cases of severe metabolic acidosis in young women without diabetes who are breastfeeding and who have used a ketogenic diet in order to quickly lose their pregnancy pounds. [ABSTRACT FROM AUTHOR]