Decreased Glucagon‐like Peptide 1 Release after Weight Loss in Overweight/Obese Subjects

Objective: Postprandial glucagon‐like peptide 1 (GLP‐1) release seems to be attenuated in obese subjects. Results on whether weight loss improves GLP‐1 release are contradictory. The aim of this study was to further investigate the effect of weight loss on basal and postprandial GLP‐1 release in overweight/obese subjects. Research Methods and Procedures: Thirty‐two overweight/obese subjects participated in a repeated measurement design before (BMI, 30.3 ± 2.8 kg/m²; waist circumference, 92.6 ± 7.8 cm; hip circumference, 111.1 ± 7.4 cm) and after a weight loss period of 6 weeks (BMI, 28.2 ± 2.7 kg/m²; waist circumference, 85.5 ± 8.5 cm; hip circumference, 102.1 ± 9.2 cm). During weight loss, subjects received a very‐low‐calorie diet (Optifast) to replace three meals per day. Subjects came to the laboratory fasted, and after a baseline blood sample, received a standard breakfast (1.9 MJ). Postprandially, blood samples were taken every one‐half hour relative to intake for 120 minutes to determine GLP‐1, insulin, glucose, and free fatty acids from plasma. Appetite ratings were obtained with visual analog scales. Results: After weight loss, postprandial GLP‐1 concentrations at 30 and 60 minutes were significantly lower than before weight loss (p < 0.05). Glucose concentrations were also lower, and free fatty acids were higher compared with before weight loss. Ratings of satiety were increased, and hunger scores were decreased after weight loss (p < 0.05). Discussion: In overweight/obese subjects, GLP‐1 concentrations after weight loss were decreased compared with before weight loss, and nutrient‐related stimulation was abolished. This might be a response to a proceeding negative energy balance. Satiety and GLP‐1 seem to be unrelated in the long term.     

The effects of Goami No. 2 rice, a natural fiber-rich rice, on body weight and lipid metabolism

Objective : Increased intake of dietary fiber reduces the risk of obesity and type 2 diabetes. We assessed the effects of a fiber‐rich diet on body weight, adipokine concentrations, and the metabolism of glucose and lipids in non‐obese and obese subjects in Korea, where rice is the main source of dietary carbohydrates. Research Methods and Procedures : Eleven healthy, non‐obese and 10 obese subjects completed two 4‐week phases of individual isoenergetic food intake. During the control diet phase, subjects consumed standard rice; during the modified diet phase, subjects consumed equal proportions of fiber‐rich Goami No. 2 rice and standard rice. We used a randomized, controlled, crossover study design with a washout period of 6 weeks between the two phases. Results : After the modified diet phase, body weight was significantly lower in both the non‐obese and obese subjects (non‐obese, 57.0 ± 2.9 vs. 56.1 ± 2.8 kg, p = 0.001; obese, 67.7 ± 2.1 vs. 65.7 ± 2.0 kg, p < 0.001 for before vs. after). The BMI was significantly lower in obese subjects (26.9 ± 0.5 vs. 26.0 ± 0.6 kg/m², p < 0.001). The modified diet was associated with lower serum triacylglycerol (p < 0.01), total cholesterol (p < 0.01), low‐density lipoprotein cholesterol (p < 0.05), and C‐peptide (p < 0.05) concentrations in the obese subjects. Discussion : These results indicate that fiber‐rich Goami No. 2 rice has beneficial effects and may be therapeutically useful for obese subjects.     

Central Exendin‐4 Infusion Reduces Body Weight without Altering Plasma Leptin in (fa/fa) Zucker Rats

Objective: To investigate whether chronic administration of the long‐acting glucagon‐like peptide‐1 receptor agonist exendin‐4 can elicit sustained reductions in food intake and body weight and whether its actions require an intact leptin system. Research Methods and Procedures: Male lean and obese Zucker (fa/fa) rats were infused intracerebroventricularly with exendin‐4 using osmotic minipumps for 8 days. Results: Exendin‐4 reduced body weight in both lean and obese Zucker rats, maximum suppression being reached on Day 5 in obese (8%) and Day 7 in lean (16%) rats. However, epididymal white adipose tissue weight was not reduced, and only in lean rats was there a reduction in plasma leptin concentration. Food intake was maximally suppressed (by 81%) on Day 3 in obese rats but was reduced by only 18% on Day 8. Similarly, in lean rats food intake was maximally reduced (by 93%) on Day 4 of treatment and by 45% on Day 8. Brown adipose tissue temperature was reduced from Days 2 to 4. Plasma corticosterone was elevated by 76% in lean but by only 28% in obese rats. Discussion: Chronic exendin‐4 treatment reduced body weight in both obese and lean Zucker rats by reducing food intake: metabolic rate was apparently suppressed. These effects did not require an intact leptin system. Neither does the absence of an intact leptin system sensitize animals to exendin‐4. Partial tolerance to the anorectic effect of exendin‐4 in lean rats may have been due to elevated plasma corticosterone and depressed plasma leptin levels, but other counter‐regulatory mechanisms seem to play a role in obese Zucker rats.     

Bupropion for Weight Loss: An Investigation of Efficacy and Tolerability in Overweight and Obese Women

Objective: On the basis of the clinical observations that bupropion facilitated weight loss, we investigated the efficacy and tolerability of this drug in overweight and obese adult women. Research Methods and Procedures: A total of 50 overweight and obese (body mass index: 28.0 to 52.6 kg/m²) women were included. The core component of the study was a randomized, double‐blind, placebo‐controlled comparison for 8 weeks. Bupropion or placebo was started at 100 mg/d with gradual dose increase to a maximum of 200 mg twice daily. All subjects were prescribed a 1600 kcal/d balanced diet and compliance was monitored with food diaries. Responders continued the same treatment in a double‐blind manner for an additional 16 weeks to a total of 24 weeks. There was additional single‐blind follow‐up treatment for a total of 2 years. Results: Subjects receiving bupropion achieved greater mean weight loss (last‐observation‐carried‐forward analysis) over the first 8 weeks of the study (p = 0.0001): 4.9% ± 3.4% (n = 25) for bupropion treatment compared with 1.3% ± 2.4% (n = 25) for placebo treatment. For those who completed the 8 weeks, the comparison was 6.2% ± 3.1% (n = 18) vs. 1.6% ± 2.9% (n = 13), respectively(p = 0.0002), with 12 of 18 of the bupropion subjects (67%) losing over 5% of baseline body weight compared with 2 of 13 in the placebo group (15%; p = 0.0094). In the continuation phase, 14 bupropion responders who completed 24 weeks achieved weight loss of 12.9% ± 5.6% with fat accounting for 73.5% ± 3.7% of the weight lost and no change in bone mineral density as assessed by DXA. Bupropion was generally well‐tolerated in this sample. Discussion: Bupropion was more effective than placebo in achieving weight loss at 8 weeks in overweight and obese adult women in this preliminary study. Initial responders to bupropion benefited further in the continuation phase.     

S 23521 Decreases Food Intake and Body Weight Gain in Diet‐Induced Obese Rats

Objective: To investigate the effect of S 23521, a new glucagon‐like peptide‐1‐(7‐36) amide analogue, on food intake and body weight gain in obese rats, as well as on gene expression of several proteins involved in energy homeostasis. Research Methods and Procedures: Lean and diet‐induced obese rats were treated with either S 23521 or vehicle. S 23521 was given either intraperitoneally (10 or 100 μg/kg) or subcutaneously (100 μg/kg) for 14 and 20 days, respectively. Because the low‐dose treatment did not affect food intake and body weight, the subcutaneous treatment at high dose was selected to test the effect on selected end‐points. Results: Treated obese rats significantly decreased their cumulative energy intake in relation to vehicle‐treated counterparts (3401 ± 65 vs. 3898 ± 72 kcal/kg per 20 days; p < 0.05). Moreover, their body weight gain was reduced by 110%, adiposity was reduced by 20%, and plasma triglyceride levels were reduced by 38%. The treatment also improved glucose tolerance and insulin sensitivity of obese rats. Regarding gene expression, no changes in uncoupling protein‐1, uncoupling protein‐3, leptin, resistin, and peroxisome proliferator‐activated receptor (PPAR)‐γ were observed. Discussion: S 23521 is an effective glucagon‐like peptide‐1‐(7‐36) amide analogue, which induced a decrease in energy intake, body weight, and adiposity in a rat model of diet‐induced obesity. In addition, the treatment also improved glucose tolerance and insulin sensitivity of obese rats. These results strongly support S 23521 as a putative molecule for the treatment of obesity.     

Increase of neuronal histamine in obese rats is associated with decreases in body weight and plasma triglycerides

Objective: The purpose of the present study was to examine the metabolic effects of a specific histamine H₃ receptor antagonist, the cinnamic amide NNC 0038‐0000‐1202 (NNC 38‐1202). Research Methods and Procedures: Effects of NNC 38‐1202 on paraventricular levels of histamine and acute effects on food intake were followed in normal rats, whereas effects on body weight homeostasis and lipid metabolism were studied in a rat model of diet‐induced obesity (DIO). Results: NNC 38‐1202, administered as single oral doses of 15 and 30 mg/kg, significantly (p < 0.01) increased paraventricular histamine by 339 ± 54% and 403 ± 105%, respectively, compared with basal levels. The same doses produced significant (p < 0.01) reductions in food intake. In DIO rats receiving NNC 38‐1202 in a daily dose of 5 mg/kg for 22 days, a decrease in food intake was associated with a significant (p < 0.001) net loss of body weight (?11.0 ± 4.8 grams), compared with rats receiving vehicle, which gained 13.6 ± 3.0 grams. Also, NNC 38‐1202 significantly (p < 0.05) reduced plasma triglycerides by ～42%, in parallel with increases in plasma free fatty acids and β‐hydroxybutyrate levels. Despite reductions in food intake and body weight following administration of NNC 38‐1202, no sign of a decrease in energy expenditure was observed, and whole‐body lipid oxidation was significantly (p < 0.05) increased in the period after dosing. Discussion: The present study suggests that antagonistic targeting of the histamine H₃ receptor decreases food intake, body weight, and plasma TG levels and, thus, represents an interesting approach to treatment of obesity and associated hyperlipidemia.     

Effects of Exendin‐4 Alone and With Peptide YY3–36 on Food Intake and Body Weight in Diet‐Induced Obese Rats

Significant weight loss following Roux‐en‐Y gastric bypass surgery (RYGB) in obese humans correlates with enhanced secretion of anorexigenic gut hormones glucagon‐like peptide‐1 (GLP‐1) and peptide YY_3–36 (PYY_3–36). Our aim here was to identify a dosing strategy for intraperitoneal (IP) infusion of GLP‐1 homologue exendin‐4 alone and with PYY_3–36 that produces a sustained reduction in daily food intake and body weight in diet‐induced obese (DIO) rats. We tested 12 exendin‐4 strategies over 10 weeks. Exendin‐4 infused during the first and last 3 h of the dark period at 15–20 pmol/h (0.15 nmol/kg/day) produced a sustained 24 ± 1% reduction in daily food intake for 17 days, and decreased body weight by 7%. In a separate group of DIO rats, none of seven dosing strategies combining exendin‐4 and PYY_3–36 produced a similar reduction in daily food intake for >10 days. The subsequent decline in efficacies of exendin‐4 alone and with PYY_3–36 on food intake and body weight in each experiment suggested possible receptor downregulation and tolerance to treatments. However, when treatments were discontinued for 1 day following losses in efficacies, daily food intake significantly increased. Together, these results demonstrate that (i) intermittent IP infusion of a low dose of exendin‐4 can produce a relatively prolonged reduction in daily food intake and body weight in DIO rats, (ii) co‐infusion of exendin‐4 and PYY_3–36 does not further prolong this response, and (iii) activation of an orexigenic mechanism gradually occurs to counteract the inhibitory effects of exendin‐4 alone and with PYY_3–36 on food intake and body weight.     

Do Obese Eat Faster Than Lean Subjects? Food Intake Studies in Pima Indian Men

Food intake rate has previously been derived from observation of eating behavior in laboratory settings or in public eating establishments. Although it has been suggested that obese individuals eat faster than lean individuals, observations of such an “obese eating style” have yielded mixed results. In the present study, the relationship between ad-libitum food intake rate and obesity was evaluated over 4 days on a metabolic ward in 28 healthy Pima Indian men (Mean ± SD; 29 ± 7 y, 100.4 ± 27.1 kg, 33 ± 10% body fat) using an automated food selection system containing a large variety of foods . Total energy intake averaged 18829 ± 3299 kJ/d consisting of 47 ± 4,40 ± 3, and 13 ± 1 percent of carbohydrate, fat and protein, respectively. The average meal duration was 25 ± 7 min. Food intake rate was 68 ± 21 g/min while carbohydrate, fat and protein intake rates were 23 ± 6, 9 ± 3 and 6 ± 2 g/min, respectively. Food intake rate correlated negatively with %body fat (1=0.61, P<0.01). Similar relationships were found between the intake rates of carbohydrate, fat and protein and body fatness. Only prospective studies will indicate whether a slow food intake rate may contribute to the etiology of obesity by possibly reducing satiety .     

Low Plasma Leptin Concentration and Low Rates of Fat Oxidation in Weight‐Stable Post‐Obese Subjects

Objective: A low resting metabolic rate for a given body size and composition, a low rate of fat oxidation, low levels of physical activity, and low plasma leptin concentrations are all risk factors for body weight gain. The aim of the present investigation was to compare resting metabolic rate (RMR), respiratory quotient (RQ), levels of physical activity, and plasma leptin concentrations in eight post‐obese adults (2 males and 6 females; 48.9 ± 12.2 years; body mass index [BMI]: 24.5 ± 1.0 kg/m²; body fat 33 ± 5%; mean ± SD) who lost 27.1 ± 21.3 kg (16 to 79 kg) and had maintained this weight loss for ≥2 months (2 to 9 months) to eight age‐ and BMI‐matched control never‐obese subjects (1 male and 7 females; 49.1 ± 5.2 years; BMI 24.4 ± 1.0 kg/m²; body fat 33 ± 7%). Research Methods and Procedures: Following 3 days of weight maintenance diet (50% carbohydrate and 30% fat), RMR and RQ were measured after a 10‐hour fast using indirect calorimetry and plasma leptin concentrations were measured using radioimmunoassay. Levels of physical activity were estimated using an accelerometer over a 48‐hour period in free living conditions. Results: After adjustment for fat mass and fat‐free mass, post‐obese subjects had, compared with controls, similar levels of physical activity (4185 ± 205 vs. 4295 ± 204 counts) and similar RMR (1383 ± 268 vs. 1430 ± 104 kcal/day) but higher RQ (0.86 ± 0.04 vs. 0.81 ± 0.03, p < 0.05). Leptin concentration correlated positively with percent body fat (r = 0.57, p < 0.05) and, after adjusting for fat mass and fat‐free mass, was lower in post‐obese than in control subjects (4.5 ± 2.1 vs. 11.6 ± 7.9 ng/mL, p < 0.05). Discussion: The low fat oxidation and low plasma leptin concentrations observed in post‐obese individuals may, in part, explain their propensity to relapse.     

The Effects of Consuming Frequent,Higher Protein Meals on Appetite and Satiety During Weight Loss in Overweight/Obese Men

The purpose of this study was to determine the effects of dietary protein and eating frequency on perceived appetite and satiety during weight loss. A total of 27 overweight/obese men (age 47 ± 3 years; BMI 31.5 ± 0.7 kg/m²) were randomized to groups that consumed an energy‐restriction diet (i.e., 750 kcal/day below daily energy need) as either higher protein (HP, 25% of energy as protein, n = 14) or normal protein (NP, 14% of energy as protein, n = 13) for 12 weeks. Beginning on week 7, the participants consumed their respective diets as either 3 eating occasions/day (3‐EO; every 5 h) or 6 eating occasions/day (6‐EO; every 2 h), in randomized order, for 3 consecutive days. Indexes of appetite and satiety were assessed every waking hour on the third day of each pattern. Daily hunger, desire to eat, and preoccupation with thoughts of food were not different between groups. The HP group experienced greater fullness throughout the day vs. NP (511 ± 56 vs. 243 ± 54 mm · 15 h; P < 0.005). When compared to NP, the HP group experienced lower late‐night desire to eat (13 ± 4 vs. 27 ± 4 mm, P < 0.01) and preoccupation with thoughts of food (8 ± 4 vs. 21 ± 4 mm; P < 0.01). Within groups, the 3 vs. 6‐EO patterns did not influence daily hunger, fullness, desire to eat, or preoccupation with thoughts of food. The 3‐EO pattern led to greater evening and late‐night fullness vs. 6‐EO but only within the HP group (P < 0.005). Collectively, these data support the consumption of HP intake, but not greater eating frequency, for improved appetite control and satiety in overweight/obese men during energy restriction‐induced weight loss.     

The Novel Antiobesic HMR1426 Reduces Food Intake without Affecting Energy Expenditure in Rats

Objective: To determine the effect of acute and chronic administration of a new food intake‐reducing compound (HMR1426) with novel mode of action (retardation of gastric emptying) on body weight development, food intake, and energy metabolism in rats. Research Methods and Procedures: Adult male Shoe‐Wistar rats were implanted with transponders allowing registration of body temperature (T_b) and locomotor activity. HMR1426 (10 or 50 mg/kg) was given orally, and acute (8 hours) and chronic (15 days) effects were measured on food intake, T_b, activity, total energy expenditure (indirect calorimetry), and epididymal adipose tissue mass. The effect of chronic treatment was compared with the effect of sibutramine (10 mg/kg). Results: HMR1426 (50 mg/kg) caused an acute and chronic decrease of food intake. There was no effect on the level and daily pattern of total energy expenditure, T_b, and locomotor activity. Respiratory quotient was acutely decreased by HMR1426 due to reduced food intake. Chronic treatment with HMR1426 decreased weight gain by 31% and epididymal white fat by 24%. Sibutramine caused a respective reduction of 48% and 35%. Energy efficiency was not affected by HMR1426 in contrast to sibutramine, which reduced energy efficiency and transiently increased activity. Discussion: HMR1426 showed an anorectic potential in rats and decreased body weight and fat mass. This was achieved solely by reducing food intake without influencing overall energy expenditure or behavior suggesting a peripheral mode of action. Thus, HMR1426 can be considered a potential new drug for obesity treatment.     

Serum Leptin Concentrations and Weight Gain in Postobese,Postmenopausal Women

Objective : This study was designed to determine if serum leptin concentrations (adjusted for fat mass) after weight loss on a low-calorie diet predict subsequent weight gain. Research Methods and Procedures : Body composition and serum leptin concentrations were determined on 14 moderately obese, postmenopausal, nondiabetic women with a familial predisposition to obesity. Assessments were obtained under tightly controlled metabolic ward conditions of macronutrient intake and weight maintenance both before (obese state) and after a mean weight loss of 12.0 kg to normal body weight (postobese state). Four years later, without intervention, body weight and body composition were reassessed. Results : Weight loss resulted in significant decreases in fat mass (29.7 ± 5.4 vs. 20.3 ± 4.7; kg), body mass index (27.7 ± 1.6 vs. 23.0 ± 1.5; kg/m2), percent body fat (40.7 ± 4.3 vs. 33.1 ± 5.0), and serum leptin concentrations (31.8 ± 16.0 vs. 11.5 ± 5.4; ng/mL). Serum leptin concentrations were positively correlated (p<<0.05) with fat mass in both the obese and postobese states (r = 0.67 and r = 0.56, respectively). However, residual serum leptin concentrations (adjusted for fat mass) in the obese and postobese states were not related to changes in body weight (p<= 0.61 and 0.52), fat mass (p = 0.72 and 0.42), body mass index (p = 0.59 and 0.33), or percent body fat (p = 0.84 and 0.46) over the follow-up period. Discussion : These finding do not support the hypothesis that relatively low concentrations of leptin predict weight regain after weight loss. However, because the number of subjects in this study was limited, further studies are warranted.     

Successful long-term weight maintenance: a 2-year follow-up

Objective: To find factors associated with successful weight maintenance (WM) in overweight and obese subjects after a very low‐calorie diet (VLCD). Research Methods and Procedures: Subjects (133) followed a VLCD (2.1 MJ/d) for 6 weeks in a free‐living situation. Of these, 103 subjects (age, 49.6 ± 9.7 years; BMI, 30.9 ± 3.8 kg/m²) completed the following 2‐year WM period. Body weight (BW), body composition, leptin concentration, attitude toward eating, and physical activity were determined right before (t0) and after (t1) the VLCD, after 3 months (t2), after 1 year (t3), after 1.5 years (t4), and after 2 years (t5). Results: BW loss during VLCD was 7.2 ± 3.1 kg. After 2 years, follow‐up BW regain was 69.0 ± 98.4%. After 2 years of WM, 13 subjects were successful (<10% BW regain), and 90 were unsuccessful (>10% BW regain). At baseline, these groups were significantly different in BMI (33.7 ± 4.7 vs. 30.5 ± 3.5 kg/m², respectively; p < 0.05) and fat mass (38.3 ± 9.8 vs. 32.1 ± 8.3 kg, p < 0.05). Successful subjects increased their dietary restraint significantly more during the whole study period (dietary restraint score, ?4.9 ± 4.4 vs. ?2.1 ± 3.8). Furthermore, %BW regain was associated with the amount of percentage body fat lost during VLCD, which indicates that the more fat lost, the better the WM, suggesting a fat free mass‐sparing effect. Discussion: Characteristics such as the ability to increase dietary restraint and maintain this high level of restraint, fat free mass sparing, and a relatively high baseline BMI and fat mass were associated with successful long‐term WM (<10% regain after 2 years).     

Energy‐Dense Snack Food Intake in Adolescence: Longitudinal Relationship to Weight and Fatness

Objective: The longitudinal relationship between the consumption of energy‐dense snack (EDS) foods and relative weight change during adolescence is uncertain. Using data from the Massachusetts Institute of Technology Growth and Development Study, the current analysis was undertaken to examine the longitudinal relationship of EDS food intake with relative weight status and percentage body fat and to examine how EDS food consumption is related to television viewing. Research Methods and Procedures: One hundred ninety‐six nonobese premenarcheal girls 8 to 12 years old were enrolled between 1990 and 1993 and followed until 4 years after menarche. At each annual follow‐up visit, data were collected on percentage body fat (%BF), BMI z score, and dietary intake. Categories of EDS foods considered were baked goods, ice cream, chips, sugar‐sweetened soda, and candy. Results: At study entry, girls had a mean ± SD BMI z score of ?0.27 ± 0.89, consumed 2.3 ± 1.7 servings of EDS foods per day, and consumed 15.7 ± 8.1% of daily calories from EDS foods. Linear mixed effects modeling indicated no relationship between BMI z score or %BF and total EDS food consumption. Soda was the only EDS food that was significantly related to BMI z score over the 10‐year study period, but it was not related to %BF. In addition, a significant, positive relationship was observed between EDS food consumption and television viewing. Discussion: In this cohort of initially nonobese girls, overall EDS food consumption does not seem to influence weight status or fatness change over the adolescent period.     

Liver Volume and Visceral Obesity in Women with Hepatic Steatosis Undergoing Gastric Banding

Objective: To investigate the relationships between visceral obesity and hepatic steatosis in obese patients undergoing adjustable silicone gastric banding with the LAP‐BAND. Research Methods and Procedures: Six premenopausal, morbidly obese women with an ultrasonographic diagnosis of liver steatosis were evaluated before surgery and 8 and 24 weeks after surgery. Liver volume and body fat distribution were simultaneously analyzed by total‐body multislices magnetic resonance imaging. Results: Before surgery, the only variable found to be correlated with liver volume was visceral adipose tissue volume (r = 0.91; p < 0.01). Weight loss was 9.9 ± 3.8 kg in the period from 0 to 8 weeks (p < 0.01) and 7.1 ± 4.9 kg in the the period from 8 to 24 weeks (p < 0.05). Total fat showed a statistically significant reduction of 6.2 ± 4.0 liters in the 0‐ to 8‐week period and a further significant reduction of 7.7 ± 3.9 liters in the 8‐ to 24‐week period. Visceral adipose tissue showed a statistically significant reduction of 1.0 ± 0.9 liters in the 0‐ to 8‐week period (p < 0.05) but only a further, not significant reduction of 0.6 ± 0.7 liters in the 8‐ to 24‐week period. The relative reduction of visceral fat in the 0‐to 8‐week period was higher than the relative reduction of total fat. Liver volume also showed a statistically significant reduction of 0.24 ± 0.26 liters in the first phase of weight loss (p < 0.05), corresponding to a relative reduction of 12.3 ± 10.6%. During the 8‐ to 24‐week period, liver volume was substantially stable. Discussion: Hepatomegaly was associated with visceral obesity in morbidly obese women with liver steatosis. In the phase of rapid weight loss after gastric surgery, a preferential mobilization of visceral fat, compared with total adipose tissue, occurred. This preferential visceral fat loss was associated with a significant reduction in liver volume.     

Effects of Two Conjugated Linoleic Acid Isomers on Body Fat Mass in Overweight Humans

Objective: To examine the effects of two different conjugated linoleic acid (CLA) isomers at two different intakes on body composition in overweight humans. Research Methods and Procedures: Eighty‐one middle‐aged, overweight, healthy men and women participated in this bicentric, placebo‐controlled, double‐blind, randomized study. For 6 weeks (run‐in period), all subjects consumed daily a drinkable dairy product containing 3 g of high oleic acid sunflower oil. Volunteers were then randomized over five groups receiving daily either 3 g of high oleic acid sunflower oil, 1.5 g of cis‐9, trans‐11 (c9t11) CLA, 3 g of c9t11 CLA, 1.5 g of trans‐10, cis‐12 (t10c12) CLA, or 3 g of t10c12 CLA administrated as triacylglycerol in a drinkable dairy product for 18 weeks. Percentage body fat mass and fat and lean body mass were assessed at the end of the run‐in and experimental periods by DXA. Dietary intake was also recorded. Results: Body fat mass changes averaged 0.1 ± 0.9 kg (mean ± SD) in the placebo group and ?0.3 ± 1.4, ?0.8 ± 2.1, 0.0 ± 2.3, and ?0.9 ± 1.7 kg in the 1.5‐g c9t11, 3‐g c9t11, 1.5‐g t10c12, and 3‐g t10c12 groups, respectively. Changes among the groups were not significantly different (p = 0.444). Also, lean body mass and dietary intake were not significantly different among the treatments. Discussion: A daily consumption of a drinkable dairy product containing up to 3 g of CLA isomers for 18 weeks had no statistically significant effect on body composition in overweight, middle‐aged men and women.     

Provision of Foods Differing in Energy Density Affects Long‐Term Weight Loss

Objective: The energy density (kilocalories per gram) of foods influences short‐term energy intake. This 1‐year clinical trial tested the effect on weight loss of a diet incorporating one or two servings per day of foods equal in energy but differing in energy density. Research Methods and Procedures: Dietitians instructed 200 overweight and obese women and men to follow an exchange‐based energy‐restricted diet. Additionally, subjects were randomized to consume daily either one or two servings of low energy‐dense soup, two servings of high energy‐dense snack foods, or no special food (comparison group). Results: All four groups showed significant weight loss at 6 months that was well maintained at 12 months. The magnitude of weight loss, however, differed by group (p = 0.006). At 1 year, weight loss in the comparison (8.1 ± 1.1 kg) and two‐soup (7.2 ± 0.9 kg) groups was significantly greater than that in the two‐snack group (4.8 ± 0.7 kg); weight loss in the one‐soup group (6.1 ± 1.1 kg) did not differ significantly from other groups. Weight loss was significantly correlated with the decrease in dietary energy density from baseline at 1 and 2 months (p = 0.0001) but not at 6 and 12 months. Discussion: On an energy‐restricted diet, consuming two servings of low energy‐dense soup daily led to 50% greater weight loss than consuming the same amount of energy as high energy‐dense snack food. Regularly consuming foods that are low in energy density can be an effective strategy for weight management.     

Sibutramine Treatment in Obesity: Predictors of Weight Loss Including Rorschach Personality Data

Objective: To study personality and clinical factors in weight loss by sibutramine (Meridia and Reductil), an anti‐obesity drug enhancing satiety. Research Methods and Procedures: The subjects were 30 obese patients [43 ± 12 years (mean ± SD), BMI 40 ± 4 kg/m²]. The treatment comprised 15 mg of sibutramine administered daily and monthly dietary advice. Weight loss after 6 months of treatment was evaluated. For psychological assessment, the Rorschach method (Comprehensive System) and the Beck Depression Inventory were used. Results: A multiple linear regression model including the Rorschach predictors’ physical demand states (animal movement, designated as FM) being intrusive or difficult to hold and a dependency orientation (food contents) could explain 47% of 6 months of weight loss. A model including initial weight loss in addition to the Rorschach predictors explained 58% of the 6‐month weight loss. Discussion: The personality factors predicted greater weight loss. In particular, patients with difficulties concerning physical demand states, which would include hunger, could have reduced their eating behavior with enhanced satiety, resulting in greater weight loss. Enhanced satiety could also have helped patients with a dependent need for food to limit food intake. Being enrolled in a treatment program could also have provided essential support for patients with dependency needs. Furthermore, initial weight loss was a predictor of greater weight loss in sibutramine treatment, in accordance with prior research.     

Weight loss strategies for obese adults: personalized weight management program vs. standard care

Objective: The objective of this study was to evaluate the effect of a 32‐week personalized Polar weight management program (PWMP) compared with standard care (SC) on body weight, body composition, waist circumference, and cardiorespiratory fitness in overweight or obese adults. Research Methods and Procedures: Overweight or obese (29 ± 2 kg/m²) men and women (n = 74) 38 ± 5 years of age were randomly assigned into either PWMP (men = 20, women = 21) or SC (men = 15, women = 18). Both groups managed their own diet and exercise program after receiving the same standardized nutrition and physical activity advice. PWMP also received a weight management system with literature to enable the design of a personalized diet and exercise weight loss program. Body weight and body composition, waist circumference, and cardiorespiratory fitness were measured at weeks 0, 16, and 32. Results: Eighty percent of participants completed the 32‐week intervention, with a greater proportion of the dropouts being women (PWMP: 2 men vs. 7 women; SC: 2 men vs. 4 women). At 32 weeks, PWMP completers had significantly (p < 0.001) greater losses in body weight [6.2 ± 3.4 vs. 2.6 ± 3.6 (standard deviation) kg], fat mass (5.9 ± 3.4 vs. 2.2 ± 3.6 kg), and waist circumference (4.4 ± 4.5 vs. 1.0 ± 3.6 cm). Weight loss and fat loss were explained by the exercise energy expenditure completed and not by weekly exercise duration. Discussion: More effective weight loss was achieved after treatment with the PWMP compared with SC. The results suggest that the PWMP enables effective weight loss through tools that support self‐monitoring without the requirement of more costly approaches to program supervision.     

Influence of weekend lifestyle patterns on body weight

Objective: To determine whether alterations in diet and/or activity patterns during weekends contribute to weight gain or hinder weight loss. Methods and Procedures: Randomized, controlled trial comparing 1 year of caloric restriction (CR) with 1 year of daily exercise (EX). Subjects included 48 healthy adults (30F, 18M) aged 50–60 years with BMI 23.5–29.9 kg/m². Body weight was measured on 7 consecutive mornings for a total of 165 weeks at baseline and 437 weeks during the 1‐year interventions. Daily weight changes were calculated for weekends (Friday to Monday) and weekdays (Monday to Friday). Daily energy intake was estimated using food diaries; daily physical activity was measured using accelerometers. Both measures were validated against doubly labeled water (DLW). Results: At baseline, participants consistently gained weight on weekend days (+0.06 ± 0.03 kg/day, (mean ± s.e.), P = 0.02), but not on weekdays (?0.02 ± 0.02 kg/day, P = 0.18). This was attributable to higher dietary intake on Saturdays and lower physical activity on Sundays relative to weekdays (both P < 0.05). During the interventions, both CR and EX participants were in negative energy balance on weekdays (P < 0.005). On weekends, however, CR participants stopped losing weight, and EX participants gained weight (+0.08 ± 0.03 kg/day, P < 0.0001) due to higher dietary intakes on weekends. This helps to explain the slower‐than‐expected rate of weight loss during the interventions. Discussion: Alterations in lifestyle behaviors on weekends contribute to weight gain or cessation of weight loss on weekends. These results provide one explanation for the relatively slow rates of weight loss observed in many studies, and the difficulty with maintaining significant weight loss.