Meal-related changes in ghrelin, peptide YY, and appetite in normal weight and overweight children

Objective: Ghrelin and peptide YY (PYY) are two gut hormones that have effects on appetite. Our objectives were to characterize the patterns of secretion of these hormones in response to feeding in school‐age children and determine whether there were differences between normal weight (NW) and overweight (OW) subjects. Methods and Procedures: This was a cross‐sectional study at one tertiary care center. Subjects were 7‐ to 11‐year‐old healthy NW and OW volunteers recruited from local advertisements. Following an overnight fast, the subjects were given a standardized breakfast and lunch and had nine hourly blood samples for total ghrelin and total PYY. We assessed whether ghrelin and PYY levels changed from the preprandial to postprandial state and corresponded to reported hunger/satiety. Results: Hunger ratings were similar between the two groups throughout the study period. Ghrelin was not suppressed after eating, did not rise prior to the next meal, and did not correspond to hunger ratings in either group. PYY increased postprandially and decreased preprandially in the NW group, but OW children exhibited this pattern for only part of the day. PYY levels incompletely corresponded to reported satiety in the OW group. Discussion: Mixed meal consumption had little effect on ghrelin secretion and a variable effect on PYY secretion in young children in our study. Differences that were observed between the groups do not suggest that an abnormality in their secretion contributes to the development of obesity.     

Metabolic syndrome in healthy obese,overweight, and normal weight individuals: The atherosclerosis risk in communities study

Objective:

There is recent interest in characterizing the subset of obese (OB) individuals who have healthy metabolic profiles yet only two studies have examined this group prospectively but not in racially diverse populations.

Design and Methods:

We analyzed factors associated with the prevalence and incidence of metabolic syndrome (MetSyn) among individuals grouped by BMI categories in a multi‐center, community‐based cohort of 14,663 African‐American and white men and women aged 45‐64 years at recruitment in 1987‐1989, the Atherosclerosis Risk in Communities (ARIC) Study. Logistic and proportional hazards regression were utilized to estimate odds ratios (ORs) for the prevalence and hazard ratios (HRs) for incidence of MetSyn with 95% confidence intervals (CIs).

Results:

At visit 1, MetSyn was positively associated with age, female gender, African‐American race, and inversely related to education, associations being more pronounced among normal weight (NW) subjects. Among those without MetSyn at visit 1, OB subjects were more likely to develop MetSyn compared with NW (HR (95% CI): 4.53 (4.09‐5.01)). Several factors were associated with incident MetSyn among NW, including older age (per year: 1.05 (1.03‐1.06)), female gender (vs. male: 1.29 (1.10‐1.52)), heavy alcohol intake (vs. never: 0.75 (0.59‐0.94)), and physical activity (tertile 3 vs. tertile 1: 0.71 (0.58‐0.86)) but not OB. Weight gain (>5%) was also more highly associated with MetSyn in NW (1.61 (1.28‐2.02)) compared with OB (1.01 (0.85‐1.20)).

Conclusions:

We conclude that lifestyle factors may play a stronger role in the development of MetSyn in NW individuals compared with OB and that metabolically healthy obesity may not be a stable condition.     

One-year changes in symptoms of depression and weight in overweight/obese individuals with type 2 diabetes in the Look AHEAD study

Depressed individuals are frequently excluded from weight loss trials because of fears that weight reduction may precipitate mood disorders, as well as concerns that depressed participants will not lose weight satisfactorily. The present study examined participants in the Look AHEAD study to determine whether moderate weight loss would be associated with incident symptoms of depression and suicidal ideation, and whether symptoms of depression at baseline would limit weight loss at 1 year. Overweight/obese adults with type 2 diabetes (n = 5,145) were randomly assigned to an Intensive Lifestyle Intervention (ILI) or a usual care group, Diabetes Support and Education (DSE). Of these, 5,129 participants completed the Beck Depression Inventory (BDI) and had their weight measured at baseline and 1 year. Potentially significant symptoms of depression were defined by a BDI score ≥10. Participants in ILI lost 8.6 ± 6.9% of initial weight at 1 year, compared to 0.7 ± 4.8% for DSE (P < 0.001, effect size = 1.33), and had a reduction of 1.4 ± 4.7 points on the BDI, compared to 0.4 ± 4.5 for DSE (P < 0.001, effect size = 0.23). At 1 year, the incidence of potentially significant symptoms of depression was significantly lower in the ILI than DSE group (6.3% vs. 9.6%) (relative risk (RR) = 0.66, 95% confidence interval (CI) = 0.5, 0.8; P < 0.001). In the ILI group, participants with and without symptoms of depression lost 7.8 ± 6.7% and 8.7 ± 6.9%, respectively, a difference not considered clinically meaningful. Intentional weight loss was not associated with the precipitation of symptoms of depression, but instead appeared to protect against this occurrence. Mild (or greater) symptoms of depression at baseline did not prevent overweight/obese individuals with type 2 diabetes from achieving significant weight loss.     

Diet-induced weight loss in overweight or obese women and changes in high-density lipoprotein levels and function

Diet-induced weight loss in women may be associated with decreases not only in plasma levels of low-density lipoprotein cholesterol (LDL-C), but also in high-density lipoprotein cholesterol (HDL-C). Whether a decrease in HDL-C is associated with altered HDL function is unknown. One hundred overweight or obese women (age 46 ± 11 years, 60 black; 12 diabetic) were enrolled in the 6-month program of reduced fat and total energy diet and low-intensity exercise. Serum cholesterol efflux capacity was measured in (3)H-cholesterol-labeled BHK cells expressing ABCA1, ABCG1, or SR-B1 transporters and incubated with 1% apolipoprotein B (apoB)-depleted serum. Antioxidant properties of HDL were estimated by paraoxonase-1 (PON1) activity and oxygen radical absorbance capacity (ORAC). Endothelial nitric oxide synthase (eNOS) activation was measured by conversion of L-arginine to L-citrulline in endothelial cells incubated with HDL from 49 subjects. Participants achieved an average weight loss of 2.2 ± 3.9 kg (P < 0.001), associated with reductions in both LDL-C (-6 ± 21 mg/dl, P = 0.004) and HDL-C (-3 ± 9 mg/dl, P = 0.016). Cholesterol efflux capacity by the ABCA1 transporter decreased by 10% (P = 0.006); efflux capacities by the ABCG1 and SR-B1 transporters were not significantly altered. ORAC decreased by 15% (P = 0.018); neither PON1 activity nor eNOS activation was significantly altered by reduction in HDL-C. Findings were similar for diabetic and nondiabetic subjects. Diet-induced weight loss in overweight or obese women is associated with a decrease in HDL-C levels, but overall HDL function is relatively spared, suggesting that decrease in HDL-C in this setting is not deleterious to cardiovascular risk.     

Disability prevalence among healthy weight,overweight, and obese adults

Objective:

Obesity is associated with adverse health outcomes in people with and without disabilities. However, little is known about disability prevalence among people who are obese. The purpose of this study is to determine the prevalence and type of disability among adults who are obese.

Design and Methods:

Pooled data from the 2003‐2009 National Health Interview Survey (NHIS) were analyzed to obtain national prevalence estimates of disability, disability type and obesity. The disability prevalence was stratified by body mass index (BMI): healthy weight (BMI 18.5‐<25.0), overweight (BMI 25.0‐<30.0), and obese (BMI ≥ 30.0).

Results:

In this pooled sample, among the 25.4% of US adults who were obese, 41.7% reported a disability. In contrast, 26.7% of those with a healthy weight and 28.5% of those who were overweight reported a disability. The most common disabilities among respondents with obesity were movement difficulty (32.5%) and work limitation (16.6%).

Conclusions:

This research contributes to the literature on obesity by including disability as a demographic in assessing the burden of obesity. Because of the high prevalence of disability among those who are obese, public health programs should consider the needs of those with disabilities when designing obesity prevention and treatment programs.     

Effect of the timing of weight cycling during adulthood on mortality risk in overweight and obese postmenopausal women

Inconsistent results exist for whether or not weight cycling (WgtC) and weight variability (WgtV) increase mortality risk. The aim of this study was to examine the effect of WgtC and WgtV during adulthood on mortality risk. Data was obtained from the Women's Health Initiative (WHI) observational study (OS) dataset, acquired from the National Heart, Lung and Blood Institute (N = 47,473 overweight and obese women; age 50–79 years). Women were categorized (stable; WgtV: weight‐gainer or loser; or WgtC) based on weight changes during early (18–35 years), mid (35–50 years), and late (50 years to current age) adulthood. Those with weight changes of <5% during all three time‐periods were classified as being stable‐weight. Weight‐gainers were those with at least one period of weight‐gain (≥5%) without a period of weight‐loss (≥5%), and weight‐losers were those with at least one period of loss without a period of gain during all time‐periods. Those who experienced both a period of weight‐gain and loss (≥5%) were categorized as WgtC. Compared to stable‐weight individuals, WgtC and WgtV across adulthood were not significantly associated with mortality risk when the age‐period of weight change was not considered. However, when considering the age period, increased mortality risk was observed for every 5 kg of weight‐gain during early (hazard ratio (HR) = 1.04 (1.00–1.07)) or mid‐adulthood (HR = 1.05 (1.02–1.08)), or for every 5 kg of weight‐loss since mid (HR = 1.12 (1.01–1.24)) or late‐adulthood (HR = 1.12 (1.04–1.20)). In conclusion, merely investigating WgtC and WgtV by weight changes across adulthood may not be sufficient to fully describe mortality risk, and the age at which the weight change occurred might be as important to consider.     

Exercise without weight loss is an effective strategy for obesity reduction in obese individuals with and without Type 2 diabetes.

It is unclear whether chronic exercise without caloric restriction or weight loss is a useful strategy for obesity reduction in obese men with and without Type 2 diabetes (T2D). We examined the effects of exercise without weight loss on total and regional adiposity and skeletal muscle mass and composition in lean men and in obese men with and without T2D. Twenty-four men participated in 13 wk of supervised aerobic exercise, five times per week for 60 min at a moderate intensity (approximately 60% peak oxygen uptake). Total and regional body composition was measured by magnetic resonance imaging. Skeletal muscle composition was determined using computed tomography. Cardiorespiratory fitness was assessed using a graded maximal treadmill test. Body weight did not change within any group in response to exercise (P > 0.1). Significant reductions in total, abdominal subcutaneous, and visceral fat were observed within each group (P < 0.01). The reduction in total and abdominal subcutaneous fat was not different (P > 0.1) between groups; however, the reduction in visceral fat was greater (P < 0.01) in the obese and T2D groups by comparison to the lean group. A significant (P < 0.01) increase in total skeletal muscle, high-density muscle area, and mean muscle attenuation was observed independent of group, and these changes were not different between groups (P > 0.1). Accordingly, whole body fat-to-muscle ratio was increased (P < 0.01) independent of groups. In conclusion, regular exercise without weight loss is associated with a substantial reduction in total and visceral fat and in skeletal muscle lipid in both obesity and T2D.     

Risk of disability and mortality due to overweight in a Finnish population.

OBJECTIVE--To investigate the effect of overweight on premature mortality and work disability in young and middle aged Finns. DESIGN--Prospective cohort study based on data collected in the multiphasic health examinations by the Social Insurance Institution of Finland from 1966 to 1972 and follow up until 1982. SETTING--34 Communities throughout Finland. SUBJECTS--12,053 Women and 19,076 men who were employed and aged 25-64 at baseline. MAIN OUTCOME MEASURES--Mortality and work disability pensions from all and specified causes. RESULTS--Body mass index was a weak predictor of death but a strong predictor of early work disability, which increased linearly with body mass index. After adjustment for age, geographical region, occupation, and smoking the relative risks of work disability for women and men with a body mass index greater than or equal to 30 kg/m2 were, respectively, 2.0 (95% confidence interval 1.8 to 2.3) and 1.5 (1.3 to 1.7) when compared with those of subjects with body mass index less than 22.5 kg/m2. The increased risks were due to an excess of cardiovascular and musculoskeletal diseases but not of mental diseases. One fourth of all disability pensions from cardiovascular and musculoskeletal causes in women and half as many in men could be attributed to overweight (body mass index greater than 25 kg/m2) alone. CONCLUSIONS--Though modest overweight has little impact on mortality it predicts severe functional impairment. A considerable proportion of work disability pensions could probably be prevented by efficient weight control.     

Moderate exercise and bright light treatment in overweight and obese individuals

Objective: Increased physical activity is important given the concern over the growing rates of obesity. The aim of this study is to conduct a controlled investigation of the effects of bright light therapy and exercise on weight loss and body composition in overweight and obese individuals. Research Methods and Procedures: Twenty‐five overweight and obese subjects were assigned to 6 weeks of moderate exercise with or without bright light treatment. Outcome measure included changes in body mass and body composition and ratings of mood, seasonality, and sleep. Results: Body weight decreased significantly with exercise in subjects in the light and non‐light treatment groups, but the change was not significantly different between the groups. Similar results were found for BMI. With exercise, body fat decreased significantly only in the light treatment group. There was a significant effect of the interaction of group by time on body fat composition, but the group by time interaction failed to reach statistical significance for body weight and BMI. Mood scores improved significantly with exercise in the light group, but no significant changes were noted regarding sleep. Discussion: This preliminary study is the first to show that addition of bright light treatment to a 6‐week moderate exercise program can alter body composition by significantly reducing body fat. The reduction in body fat mass is of particular importance, because visceral fat has been particularly implicated as a major factor in the development of the metabolic syndrome. This study is an important step toward finding ways to maximize the effects of exercise.     

Trophic changes,without changes in the external nutrient loading

The impact of the fish population on trophic properties of lake water, was experimentally studied in an oligotrophic Swedish forest lake. Biotic changes following fish removal resulted in a development in oligotrophic direction as shown by the drop in limnetic primary production, pH, total phosphorus, total nitrogen and the increased transparency.