Changes in body composition during weight loss

Studies based on conditions found in World War II and on the "Minnesota" project show that a reduced intake of energy not only reduces the amount of body fat but also (with the exception of the brain and of bones) all organs are affected to varying degrees. Body water loss is followed by water retention and, during recovery from reduced energy intake, the body fat content increases above pre-diet levels before returning to normal.     

The effect of job loss on overweight and drinking

This paper examines the impact of job loss due to business closings on body mass index (BMI) and alcohol consumption. We suggest that the ambiguous findings in the extant literature may be due in part to unobserved heterogeneity in response and in part due to an overly broad measure of job loss that is partially endogenous (e.g., layoffs). We improve upon this literature using: exogenously determined business closings, a sophisticated estimation approach (finite mixture models) to deal with complex heterogeneity, and national, longitudinal data from the Health and Retirement Study. For both alcohol consumption and BMI, we find evidence that individuals who are more likely to respond to job loss by increasing unhealthy behaviors are already in the problematic range for these behaviors before losing their jobs. These results suggest the health effects of job loss could be concentrated among “at risk” individuals and could lead to negative outcomes for the individuals, their families, and society at large.     

The effect of body weight on adolescent sexual activity

Recent research suggests that overweight females suffer penalties in the labor and marriage markets, while overweight males do not. This study explores whether similar gender differences in the effect of body weight exist in what Cawley et al. ( 2006 ) labeled ‘the adolescent sex market’. Drawing on data from the National Longitudinal Study of Adolescent Health, we use fixed effects and instrumental variables identification strategies to estimate the relationship between body weight and sexual activity. We find evidence that increased body weight lowers the probability that female adolescents become sexually active. In contrast, there is little evidence of a causal relationship between body weight and sexual activity for male adolescents. Copyright © 2010 John Wiley & Sons, Ltd.     

Patterns of body weight change affect weight loss during a multidisciplinary intervention in adolescents with obesity

AimThe current pediatric obesity health challenge necessitates a better understanding of the factors affecting weight loss success during interventions. The aim of this observational study was to test the impact of the rate of initial weight loss and body weight variability on weight loss during a 9-month residential, multidisciplinary weight loss program in adolescents with obesity.MethodsThis retrospective study considered a whole sample of 510 adolescents with obesity (12–16 years, 435 girls). Body weight assessment was performed before (T0) and each week during the 9 months of a multidisciplinary weight loss program. Initial weight change (week 4-W4) and overall weight change at week 12 (T1) and the end of the intervention (T2) were considered. Participants were divided into three groups (tertiles), based on their percentage of weight loss between T0 and W4; and weight variability was expressed by the root mean square error (RMSE) around each participant’s regression line at each considered period (W4, T1, T2).ResultsAdolescents with lower initial weight loss at W4 (tertile 3) displayed the lesser weight loss at T1 and T2 compared with adolescents in tertile 1 and 2. The RMSE was positively associated with the percentage of weight loss of the period considered, but when the analyses were adjusted for age and initial body weight, there was no more significant association.ConclusionsThe rate of weight loss during the first few weeks is crucial for weight loss success, and weight variability is positively associated with weight loss in adolescents with obesity. Overall, results show that initial body weight is a determinant characteristic to consider during a lifestyle intervention. Further studies are thus needed to better understand the relationship between body weight change patterns and weight loss during the dynamic state that is adolescence.     

孕前体重、孕期增重对新生儿出生体重的影响

目的:探讨孕妇孕前体重、孕期增重对新生儿出生体重的影响。方法:选取1 419例单胎妊娠孕妇作为研究对象。问卷调查孕妇的基本情况,定期产前检查时记录孕周并测量体重,随访研究对象妊娠结局。并采用LMS法分别建立孕妇不同孕前BMI组孕期不同周次增重的百分位数曲线。结果:超重组孕妇的新生儿出生体重最高,正常组次之,低体重组最低,三组间的差异有统计学意义(P<0.05)。孕前BMI<18.5的低体重组孕妇小于胎龄儿的检出率要高于其他两组的孕妇,差异有统计学意义(P<0.05)。LMS曲线示三组孕母孕期体重增加呈逐渐上升趋势,孕早期三组体重增重甚少,孕中期体重增加小于孕晚期。孕前低体重组孕妇孕期总增重较正常体重组和超重组多。结论:孕前体重和孕期增重与新生儿的出生体重有密切关系,应采取有效措施进行合理控制。     

茶及茶中多酚类化合物减肥作用的研究进展

近10年来,肥胖患病率明显增加,已成为现代医学最严重问题之一。据报道,茶儿茶素尤其是绿茶儿茶素具有抗肥胖作用。然而,由于茶的品种各异,萃取条件不同,以致研究结果出现不一致的结论。最新的研究发现,脂肪酸合酶与肥胖相关,而茶多酚对脂肪酸合酶具有可逆和不可逆的双重作用,这可能成为茶及茶中多酚类化合物抗肥胖作用机制研究的新途径。目前,关于茶减肥的机制性研究主要集中在绿茶及绿茶多酚方面。因此,有必要对其他茶及茶多酚减肥作用及机制进行进一步研究。     

Comparison of methods to assess body composition changes during a period of weight loss

OBJECTIVE: To assess the accuracy of body composition measurements by air displacement plethysmography and bioelectrical impedance analysis (BIA) compared with DXA during weight loss. RESEARCH METHODS AND PROCEDURES: Fifty-six healthy but overweight participants, 34 women and 22 men (age, 52 +/- 8.6 years; weight, 92.2 +/- 11.6 kg; BMI, 33.3 +/- 2.9 kg/m(2)) were studied in an outpatient setting before and after 6 months of weight loss (weight loss, 5.6 +/- 5.5 kg). Subjects were excluded if they had initiated a new drug therapy within 30 days of randomization, were in a weight loss program, or took a weight loss drug within 90 days of randomization. Subjects were randomly assigned either to a self-help program, consisting of two 20-minute sessions with a nutritionist and provision of printed materials and other self-help resources, or to attendance at meetings of a commercial program (Weight Watchers). Body composition was examined by each of the methods before and after weight loss. RESULTS: BIA (42.4 +/- 5.8%) underestimated percentage fat, whereas the BodPod (Siri = 51.7 +/- 6.9%; Brozek = 48.5 +/- 6.5%) overestimated percentage fat compared with DXA (46.1 +/- 7.9%) before weight loss. Correlation coefficients for detecting changes in body composition between DXA and the other methods were relatively high, with Brozek Deltafat mass (FM; r(2) = 0.63), Siri FM (r(2) = 0.65), tetrapolar BIA percentage fat (r(2) = 0.57), and Tanita FM (r(2) = 0.61) being the highest. DISCUSSION: In conclusion, all of the methods were relatively accurate for assessing body composition compared with DXA, although there were biases. Furthermore, each of the methods was sensitive enough to detect changes with weight loss.     

The long-term effect of advice on low-fat diets in terms of weight loss: an interim meta-analysis

Introduction: There is a wealth of evidence from a number of sources that body weight and the proportion of energy from dietary fat are directly related. However, some randomized controlled trials (RCTs) of low-fat diets versus other types of low-energy diets have found no difference in weight loss between treatment groups. Thus, the overall aim of this systematic review and meta-analysis is to assess the effectiveness of low-fat diets as a means of achieving sustained weight loss, using all available randomized clinical trials. Methods: The Cochrane Library, M EDLINE , E MBASE , B IOSIS and bibliographies will be systematically searched for relevant studies. Key journals will be hand searched and experts approached for additional studies. Interim results: The interim meta-analyses suggest that, in overweight and/or obese clients, ad libitum low-fat diets are not more efficacious than other types of low-energy diets in terms of weight loss, and also that, in the same population, low-energy low-fat diets are not more efficacious than low-energy diets which are not low in fat, in terms of weight loss. However, the studies included in the two interim meta-analyses revealed significant heterogeneity which will be examined in greater detail in the final meta-analysis. Conclusion: From our interim analyses of the data, we conclude that low-fat diets are as efficacious as other types of low-energy diets in promoting weight loss in the overweight and obese. Updates and the final report of this systematic review will be published in the Cochrane Library ( The Cochrane Library 1997 , Issue 4).     

Dietary protein and exercise have additive effects on body composition during weight loss in adult women

This study examined the interaction of 2 diets (high protein, reduced carbohydrates vs. low protein, high carbohydrates) with exercise on body composition and blood lipids in women (n = 48, approximately 46 y old, BMI = 33 kg/m(2)) during weight loss. The study was a 4-mo weight loss trial using a 2 x 2 block design (Diet x Exercise). Diets were equal in total energy (7.1 MJ/d) and lipids ( approximately 30% energy intake) but differed in protein content and the ratio of carbohydrate:protein at 1.6 g/(kg . d) and <1.5 (PRO group) vs. 0.8 g/(kg . d) and >3.5 (CHO group), respectively. Exercise comparisons were lifestyle activity (control) vs. a supervised exercise program (EX: 5 d/wk walking and 2 d/wk resistance training). Subjects in the PRO and PRO + EX groups lost more total weight and fat mass and tended to lose less lean mass (P = 0.10) than the CHO and CHO + EX groups. Exercise increased loss of body fat and preserved lean mass. The combined effects of diet and exercise were additive for improving body composition. Serum lipid profiles improved in all groups, but changes varied among diet treatments. Subjects in the CHO groups had larger reductions in total cholesterol and LDL cholesterol, whereas subjects in the PRO groups had greater reductions in triacylglycerol and maintained higher concentrations of HDL cholesterol. This study demonstrated that a diet with higher protein and reduced carbohydrates combined with exercise additively improved body composition during weight loss, whereas the effects on blood lipids differed between diet treatments.     

分阶段减重模式对超重肥胖女性减重效果的研究

目的 探讨分阶段减重模式对超重肥胖女性减重效果,为临床减重方案提供依据。方法 选取2021年1—6月在青岛市妇女儿童医院营养门诊减重的无器质疾病的超重肥胖女性46例作为研究对象,采用一阶段极低碳水化合物饮食2周,二阶段限能量平衡饮食4周,期间配合有氧、抗阻力运动。监测干预前后减重者体重、形态学指标、体成分指标的变化。数据采用重复测量方差分析进行统计学分析。结果 46例减重者经过两阶段的饮食及运动干预,体重（F = 343.033,P＜0.001）、体质指数（body mass index,BMI）（F = 331.302,P＜0.001）、腰围（F = 124.360,P＜0.001）、臀围（F = 80.558,P＜0.001）、腰臀比（F = 8.325,P = 0.002）、体脂肪（F = 255.959,P＜0.001）、内脏脂肪面积（F = 123.372,P＜0.001）、体脂率（F = 134.714,P＜0.001）均下降,差异具有统计学意义。结论 分阶段减重模式可以明显降低超重肥胖女性的体重,改善体成分,为临床减重提供思路。