Factors That Influence Food Amount Ratings by White,Hispanic, and Asian Samples

Objective: Two studies explored in nonclinical samples variables that may influence meal size assessments. Research Methods and Procedures: In Study 1, the contribution of dietary restraint, weight, depressive symptoms, and gender to ratings on the Food Amount Rating Scale was examined in 153 white women and 121 white men; in Study 2, the contribution of dietary restraint, weight, ethnicity, and ethnic group identification to Food Amount Rating Scale ratings was examined in 67 Asian, 81 Hispanic, and 107 white women. Results: Study 1 indicated that food amounts were rated as larger when rated by male rather than female raters (male rater, mean = 62.37, SD = 1.14; female rater, mean = 59.28, SD = 0.89), for female rather than male targets (male target, mean = 56.16, SD = 0.97; female target, mean = 64.87, SD = 1.02), and by restrained rather than unrestrained eaters (restrained, mean = 63.14, SD = 1.11; unrestrained, mean = 58.69, SD = 0.91). Study 2 indicated that food amounts were rated as larger when rated by restrained eaters (restrained, mean = 67.53, SD = 1.21; unrestrained, mean = 64.99, SD = 1.09), Hispanic women (Asian, mean = 64.59, SD = 1.61; Hispanic, mean = 68.71, SD = 1.30; white, mean = 65.41, SD = 1.34), and underweight women (underweight, mean = 70.38, SD = 1.68; normal weight, mean = 64.52, SD = 0.93; overweight: mean = 64.23, SD = 1.64). Discussion: Food amount judgments may be influenced by personal characteristics. Future research should examine whether variation in food amount judgments is related to dieting behavior, disordered eating, or obesity.     

On the Relation of Attempting to Lose Weight,Restraint, and Binge Eating in Outpatients with Binge Eating Disorder

Objective: To examine the relationship among attempts to lose weight, restraint, and eating behavior in outpatients with binge eating disorder (BED). Research Methods and Procedures: Participants were 93 consecutive outpatients evaluated for a clinical trial who met Diagnostic and Statistical Manual, Fourth edition criteria for BED. The Eating Disorder Examination Interview was administered to assess attempts at weight loss, restraint, different forms of overeating, and the attitudinal psychopathology of eating disorders (i.e., concerns regarding eating, shape, and weight). In addition, the Three‐Factor Eating Questionnaire was used to assess cognitive restraint, hunger, and disinhibition. Psychometrically established measures were given to assess body dissatisfaction, depression, and self‐esteem. Results: The majority of participants (75.3%; N = 70) reported attempting to lose weight, but only 37.6% (N = 35) reported dietary restraint on at least half the days of the month. Dietary restraint and cognitive restraint were not associated with any form of binge eating or overeating. Dietary restraint and cognitive restraint were positively correlated with weight concern, shape concern, and body dissatisfaction, and negatively correlated with body mass index. To further examine the interplay between attempting to lose weight and restraint, three study groups were created: unrestrained nonattempters (21.5%, N = 20), unrestrained attempters (40.9%; N = 38), and restrained attempters (34.4%; N = 32). The three groups did not differ significantly on binge eating or other eating behaviors; however, significant differences were observed for weight concern, shape concern, and body dissatisfaction. Discussion: Attempts to lose weight and restraint are not synonymous for patients with BED. Although 75.3% of BED patients reported that they were attempting to lose weight, only 37.6% reported dietary restraint on at least half the days of the previous month. While restraint was negatively associated with body mass index, it was not related to binge eating or overeating. Our findings raise questions about prevailing models that posit restraint as a predominant factor in the maintenance of binge eating in BED.     

Higher 24‐h Respiratory Quotient and Higher Spontaneous Physical Activity in Nighttime Eaters

We have previously shown that a higher 24‐h respiratory quotient (24‐h RQ) predicts greater ad‐libitum food intake and that nighttime eaters (NE) ingested more calories during an in‐patient food intake study and gained more weight over time. We investigated whether 24‐h RQ was higher in individuals who exhibited nighttime eating behavior. Healthy nondiabetic Pima Indians (PI; n = 97, 54 male/43 female) and whites (W; n = 32, 22 male/10 female) were admitted to our Clinical Research Unit. After 3 days of a weight maintaining diet, 24‐h energy expenditure (24‐h EE), 24‐h RQ, rates of carbohydrate (CHOX) and lipid oxidation (LIPOX), and spontaneous physical activity (SPA) were measured in a metabolic chamber whereas volunteers were in energy balance and unable to consume excess calories. Individuals subsequently ate ad libitum from a computerized vending machine for 3 days with amount and timing of food intake recorded. Fifty‐five individuals (36%; 39 PI, 16 W) were NE, who ate between 11 pm and 5 am on at least one of the 3 days on the vending machines. There were no differences in BMI or percentage body fat between NE and non‐NE. After adjusting for age, sex, race, fat‐free mass, fat mass, and energy balance, NE had a higher 24‐h RQ (P = 0.01), higher CHOX (P = 0.009), and lower LIPOX (P = 0.03) and higher 24‐h SPA (P = 0.04) compared to non‐NE. There were no differences in adjusted 24‐h EE or sleep RQ between the groups. Individuals with nighttime eating behavior have higher 24‐h RQ, higher CHOX and lower LIPOX, a phenotype associated with increased food intake and weight gain.     

The Val103Ile Polymorphism of Melanocortin‐4 Receptor Regulates Energy Expenditure and Weight Gain

Objective: The melanocortin‐4 receptor (MC4R) regulates energy intake. On the basis of animal studies, it may also regulate energy expenditure. Research Methods and Procedures: The effect of the Val103Ile polymorphism of the MC4R gene on energy metabolism was studied in 229 middle‐aged nondiabetic subjects (Group 1, age 51.2 ± 9.8 years, BMI 26.8 ± 4.5 kg/m²) and on weight gain in 1013 elderly subjects (Group 2, age 69.9 ± 2.9 years, BMI 27.4 ± 4.1 kg/m²) during a 3.5‐year follow‐up study. In Group 1, insulin sensitivity, energy expenditure, and substrate oxidation were measured with the hyperinsulinemic euglycemic clamp combined with indirect calorimetry. Results: In Group 1, the Val103Ile genotype was associated with high rates of energy expenditure (63.42 ± 13.40 in eight subjects with the Val103Ile genotype vs. 59.86 ± 7.33 J/kg per minute in 221 subjects with the Val103Val genotype, p = 0.007), high rates of glucose oxidation (8.90 ± 6.15 vs. 6.07 ± 4.38 μmol/kg per minute, p = 0.020), and low levels of free fatty acids (0.45 ± 0.18 vs. 0.56 ± 0.23 mM, p = 0.029) in the fasting state, and with high rates of glucose oxidation during the clamp (18.88 ± 4.63 vs. 17.60 ± 3.24 μmol/kg per minute, p = 0.031). In Group 2, the 103Ile allele was associated with an increase in weight gain during the follow‐up (0.78 ± 3.98 vs. ?0.82 ± 3.98 kg, p = 0.038). Discussion: The Val103Ile polymorphism of the MC4R gene is associated with energy expenditure in humans. Furthermore, it may associate with glucose oxidation, free fatty acid levels, and weight gain.     

Post‐Exercise Substrate Utilization after a High Glucose vs. High Fructose Meal During Negative Energy Balance in the Obese

Objective: To assess the effects of negative energy balance on the metabolic response of a meal containing either glucose or fructose as the primary source of carbohydrate after exercise in obese individuals in energy balance, or negative energy balance. Research Methods and Procedures: Fourteen adults with mean body mass index (BMI) 30.3 ± 1 kg/m², age 26 ± 2 years, and weight 93.5 ± 5.4 kg, adhered to an energy‐balanced (EB) or a negative energy‐balanced (NEB) diet for 6 days. On Day 7, subjects exercised at 70% VO_2peak for 40 minutes then consumed either high glucose (50 g of glucose, HG) or high fructose (50 g of fructose, HF) liquid meal. Substrate utilization was measured by indirect calorimetry for 3 hours. Blood samples were collected before exercise and 0, 30, 60, 120, and 180 minutes after consuming the meal. Results: The HG produced 15.9% greater glycemic (p < 0.05) and 30.9% larger insulinemic (p < 0.05) responses than the HF under both EB and NEB conditions. After the NEB diet, carbohydrate and fat oxidation did not differ for HG and HF. In contrast, carbohydrate oxidation increased 31%, and fat oxidation decreased 39% with HF compared with HG after the EB diet. Thus, HF and HG consumed after exercise produced marked differences in macronutrient oxidation when obese subjects followed an EB diet, but no difference when adhering to a NEB diet. Discussion: The data suggest that the use of fructose in supplements/meals may provide no additional benefit in terms of substrate utilization during a weight loss program involving diet and exercise.     

Inhibition Ability of Food Cues between Successful and Unsuccessful Restrained Eaters: A Two-Choice Oddball Task

BackgroundPrevious studies have presented mixed findings on the inhibition ability in restrained eaters (REs) due to the limited amount of neural evidence and limitations of behavioral measures. The current study explores the neural correlations of the specific inhibition ability among successful restrained eaters (S-REs), unsuccessful restrained eaters (US-REs), and unrestrained eaters (UREs).ConclusionResults indicate that S-REs and US-REs differ in terms of specific inhibition ability and that enhanced inhibition is essential to a successful diet.     

Association of Breakfast Skipping With Visceral Fat and Insulin Indices in Overweight Latino Youth

Few studies have investigated the relationship between breakfast consumption and specific adiposity or insulin dynamics measures in children. The goal of this study is to determine whether breakfast consumption is associated with adiposity, specifically intra‐abdominal adipose tissue (IAAT), and insulin dynamics in overweight Latino youth. Participants were a cross‐sectional sample of 93 overweight (≥85th percentile BMI) Latino youth (10–17 years) with a positive family history of type 2 diabetes. Dietary intake was assessed by two 24‐h recalls, IAAT, and subcutaneous abdominal adipose tissue (SAAT) by magnetic resonance imaging, body composition by dual energy X‐ray absorptiometry, and insulin dynamics by a frequently sampled intravenous glucose tolerance test and minimal modeling. Participants were divided into three breakfast consumption categories: those who reported not eating breakfast on either day (breakfast skippers; n = 20), those who reported eating breakfast on one of two days (occasional breakfast eaters; n = 39) and those who ate breakfast on both days (breakfast eaters; n = 34). Using analyses of covariance, breakfast omission was associated with increased IAAT (P = 0.003) independent of age, Tanner, sex, total body fat, total body lean tissue mass, and daily energy intake. There were no significant differences in any other adiposity measure or in insulin dynamics between breakfast categories. Eating breakfast is associated with lower visceral adiposity in overweight Latino youth. Interventions focused on increasing breakfast consumption are warranted.     

Effect of orlistat on eating behavior among participants in a 3-year weight maintenance trial

Objective: To examine the effect of orlistat on dietary restraint, disinhibition, hunger, and binge eating and to understand the relation between changes in eating behavior and weight maintenance. Methods and Procedures: Subjects were 306 women and men (age: 19–45 years; BMI: 37.5 ± 4.1 kg/m²) included in the Scandinavian Multicenter study of Obese subjects with the Metabolic Syndrome, a 3‐year clinical trial of orlistat or placebo following an 8‐week very low energy diet (VLED). Outcomes were changes in weight and in the Three Factor Eating Questionnaire (TFEQ) and Binge Eating Scale (BES) between screening and 17 and 33 months after randomization. As reported previously, weight gain following VLED was lower in subjects treated with orlistat than with placebo. Results: Compared to screening results, dietary restraint was increased and disinhibition, hunger, and binge eating were decreased in both groups. These changes were similar in both groups with the exception of the hunger score at month 33 that was reduced more in the placebo than in the orlistat group (difference between groups ?1.1 (95% CI (?2.0, ?0.2)) P = 0.014). In multivariate analyses, scores for restraint, disinhibition and binge eating were associated with weight loss after adjustment for BMI, gender, age, and treatment (all P ≤ 0.002, model R ² = 0.12–0.17). Discussion: Orlistat did not affect eating behavior differently in any substantial way than the placebo did in this long‐term weight maintenance trial. The results indicate that increased restraint and decreased disinhibition and binge eating are important for sustained weight maintenance in obese subjects with the metabolic syndrome.     

Dietary Restraint and Control Over “Wanting” Following Consumption of “Forbidden” Food

Eating behavior can be influenced by the rewarding value of food, i.e., “liking” and “wanting.” The objective of this study was to assess in normal‐weight dietary restrained (NR) vs. unrestrained (NU) eaters how rewarding value of food is affected by satiety, and by eating a nonhealthy perceived, dessert‐specific food vs. a healthy perceived, neutral food (chocolate mousse vs. cottage cheese). Subjects (24NR age = 25.0 ± 8.2 years, BMI = 22.3 ± 2.1 kg/m²; 26NU age = 24.8 ± 8.0 years, BMI = 22.1 ± 1.7 kg/m²) came to the university twice, fasted (randomized crossover design). Per test‐session “liking” and “wanting” for 72 items divided in six categories (bread, filling, drinks, dessert, sweets, stationery (placebo)) was measured, before and after consumption of chocolate mousse/cottage cheese, matched for energy content (5.6 kJ/g) and individual daily energy requirements (10%). Chocolate mousse was liked more than cottage cheese (P < 0.05). After consumption of chocolate mousse or cottage cheese, appetite and “liking” vs. placebo were decreased in NR and NU (P < 0.03), whereas “wanting” was only decreased in NR vs. NU (P ≤ 0.01). In NR vs. NU “wanting” was specifically decreased after chocolate mousse vs. cottage cheese; this decrease concerned especially “wanting” for bread and filling (P < 0.05). To conclude, despite similar decreases in appetite and “liking” after a meal in NR and NU, NR decrease “wanting” in contrast to NU. NR decrease “wanting” specifically for a nonhealthy perceived, “delicious,” dessert‐specific food vs. a nutritional identical, yet healthy perceived, slightly less “delicious,” “neutral” food. A healthy perceived food may thus impose greater risk for control of energy intake in NR.     

Longitudinal Adaptations to Very Low–carbohydrate Weight‐reduction Diet in Obese Rats: Body Composition and Glucose Tolerance

Longitudinal effects of a very low–carbohydrate (VLC) and a calorie‐matched high‐carbohydrate (HC) weight reduction diet were compared in dietary obese Sprague–Dawley rats exhibiting impaired glucose tolerance and insulin resistance. Obese rats were divided into weight‐matched groups: (i) VLC rats consumed an energy‐restricted 5% carbohydrate, 60% fat diet for 8 weeks, (ii) HC rats consumed an isocaloric 60% carbohydrate, 15% fat diet, and (iii) HF rats consumed a high‐fat diet ad libitum. HC and VLC rats showed similar reductions in body fat and hepatic lipid at the midpoint of the weight‐reduction program, indicating effects due to energy deficit. At the end point, however, HC rats showed greater reductions in total and percent body fat, hepatic lipid and intramuscular lipid than did VLC rats, suggesting that diet composition induced changes in the relative efficiencies of the HC and VLC diets over time. HC rats showed marked improvement in glucose tolerance at the midpoint and end point, whereas VLC rats showed no improvement. Impaired glucose tolerance in VLC rats at the end point was due to insulin resistance and an attenuated insulin secretory response. Glucose tolerance in energy‐restricted rats correlated negatively with hepatic and intramuscular lipid levels, but not visceral or total fat mass. These findings demonstrate that adaptations to diet composition eventually enabled HC rats to lose more body fat than VLC rats even though energy intakes were equal, and suggest that the elevated levels of hepatic and intramuscular lipid associated with VLC diets might predispose to insulin resistance and impaired glucose tolerance despite weight loss.     

Three-year weight change in successful weight losers who lost weight on a low-carbohydrate diet

Objective: The purpose of this study was to evaluate long‐term weight loss and eating and exercise behaviors of successful weight losers who lost weight using a low‐carbohydrate diet. Research Methods and Procedures: This study examined 3‐year changes in weight, diet, and physical activity in 891 subjects (96 low‐carbohydrate dieters and 795 others) who enrolled in the National Weight Control Registry between 1998 and 2001 and reported ≥30‐lb weight loss and ≥1 year weight loss maintenance. Results: Only 10.8% of participants reported losing weight after a low‐carbohydrate diet. At entry into the study, low‐carbohydrate diet users reported consuming more kcal/d (mean ± SD, 1895 ± 452 vs. 1398 ± 574); fewer calories in weekly physical activity (1595 ± 2499 vs. 2542 ± 2301); more calories from fat (64.0 ± 7.9% vs. 30.9 ± 13.1%), saturated fat (23.8 ± 4.1 vs. 10.5 ± 5.2), monounsaturated fat (24.4 ± 3.7 vs. 11.0 ± 5.1), and polyunsaturated fat (8.6 ± 2.7 vs. 5.5 ± 2.9); and less dietary restraint (10.8 ± 2.9 vs. 14.9 ± 3.9) compared with other Registry members. These differences persisted over time. No differences in 3‐year weight regain were observed between low‐carbohydrate dieters and other Registry members in intent‐to‐treat analyses (7.0 ± 7.1 vs. 5.7 ± 8.7 kg). Discussion: It is possible to achieve and maintain long‐term weight loss using a low‐carbohydrate diet. The long‐term health effects of weight loss associated with a high‐fat diet and low activity level merits further investigation.     

Predictors of Long‐term Weight Maintenance

Objective: The purpose of this study was to evaluate available variables of a long‐term weight maintenance study to investigate possible factors predisposing to weight regain after a period of weight loss. Research Methods and Procedures: The Maastricht Weight Maintenance Study is an ongoing longitudinal study of healthy men and women (29 men and 62 women; 18 to 65 years of age; BMI = 30.2 ± 3.1 kg/m²). A variety of parameters were measured before and after a very‐low‐energy diet and after a follow‐up of at least 2 years. Results: Mean weight loss was 7.9 ± 3.6 kg, and percent weight regain was 113.8 ± 98.1%. Percent BMI regain was negatively associated with an increase in dietary restraint (r = ?0.47, p < 0.05). Percent weight regain was negatively correlated with baseline resting metabolic rate (r = ?0.38, p = 0.01) and baseline fat mass (r = ?0.24, p = 0.05) and positively correlated with the magnitude of change in body weight (BW) expressed as maximum amplitude of BW (r = 0.21, p < 0.05). In addition, amplitude of BW was positively correlated with the frequency of dieting (r = 0.57, p < 0.01). Discussion: The best predictors for weight maintenance after weight loss were an increase in dietary restraint during weight loss, a high baseline resting metabolic rate, a relatively high baseline fat mass favoring a fat‐free mass–sparing effect during weight loss, a rather stable BW, and a low frequency of dieting. Therefore, BW maintenance after BW loss seems to be a multifactorial issue, including mechanisms that regulate an individuals’ energy expenditure, body composition, and eating behavior in such a way that energy homeostasis is maintained.     

Impact of Diet‐Induced Weight Loss on the Cardiac Autonomic Nervous System in Severe Obesity

Objective: To determine the impact of diet‐induced weight loss on cardiac autonomic nervous system modulation and arrhythmias in subjects with severe obesity and the influence of a high‐fat or a high‐carbohydrate diet regimen on heart rate variability in reduced‐obese individuals. Research Methods and Procedures: Eight severely obese subjects (BMI ≥ 40.0 kg/m²) underwent a 3‐month weight loss program followed by a 3‐month reduced‐weight maintenance regimen. Thereafter, each subject was admitted for an inpatient period of 17 days on two separate occasions. A high‐carbohydrate (60%) or high‐fat (55%) diet of appropriate energy content for weight maintenance was prescribed during each inpatient phase. Heart rate variability was derived from a 24‐hour Holter monitoring system in all subjects during their inpatient stay. Cardiac Holter monitoring was performed at three occasions (baseline, diet phase I, and diet phase II), including the second night of a two overnight calorimetry chamber stay. Results: After the diet regimen, there was a 10% decrease in weight. There were no significant changes in systolic and diastolic blood pressure, arrhythmias, glucose, insulin, total cholesterol, low‐density lipoprotein‐cholesterol, high‐density lipoprotein‐cholesterol, respiratory exchange ratio, and resting energy expenditure between experiments. Mean heart rate was lower after weight loss compared with baseline (p < 0.001). After weight loss, there was an increase in the parasympathetic indices of heart rate variability showing an increase in cardiac vagal modulation (all p < 0.05). Discussion: Weight loss is associated with significant improvement in autonomic cardiac modulation through enhancement of parasympathetic modulation, which clinically translates into a decrease in heart rate.     

Body Weight Loss and Weight Maintenance in Relation to Habitual Caffeine Intake and Green Tea Supplementation

Objective: Investigation of the effect of a green tea‐caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake. Research Methods and Procedures: A randomized placebo‐controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 ± 2.7 kg/m²) matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea‐caffeine mixture (270 mg epigallocatechin gallate + 150 mg caffeine per day) or placebo. Results: Subjects lost 5.9 ±1.8 (SD) kg (7.0 ± 2.1%) of body weight (p < 0.001). At baseline, satiety was positively, and in women, leptin was inversely, related to subjects’ habitual caffeine consumption (p < 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p < 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p < 0.01). In the high caffeine consumers, no effects of the green tea‐caffeine mixture were observed during WM. Discussion: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea‐caffeine mixture improved WM, partly through thermogenesis and fat oxidation.     

Effect of Dietary Carbohydrate Source on the Development of Obesity in Agouti Transgenic Mice**

Objectives: Our objective was to evaluate the effects of a qualitative change in dietary carbohydrate source on body weight and adiposity in a rodent model of diet‐induced obesity. Research Methods and Procedures: We evaluated the effects of high‐fat diets (basal) varying in carbohydrate source in aP2‐agouti transgenic mice. In the ad libitum study, animals were given free access to the basal diet or one of four test diets for 6 weeks. In two of the diets, dietary carbohydrate was derived from a single source: mung bean noodles (MUNG) or rolled oats (ROLL). The remaining diets were designed to mimic commercially available instant oatmeal with added sugar (IO‐S) or flavored instant oatmeal (IO‐F). In the energy‐restricted study, animals were given ad libitum access to the basal diet for 6 weeks. Subsequently, animals were assigned to one of six treatment groups for 6 weeks. One group was continued on the basal diet ad libitum. The remaining groups were maintained with energy restriction (70% ad libitum) on either the basal, MUNG, ROLL, IO‐S, or IO‐F diet. Results: Subcutaneous fat pad mass was significantly higher (p < 0.05) in the energy‐restricted basal and IO‐S groups compared with the energy‐restricted ROLL diet. Similarly, visceral fat pad mass was significantly lower with ROLL and MUNG diets (p < 0.05 for both) compared with basal and IO‐S diets, and the insulin:glucose ratio was reduced (by 23% to 34%, p < 0.05) in these two diets compared with all others. In ad libitum‐fed animals, liver fatty acid synthase expression was 43% to 62% lower (p < 0.05) with ROLL and MUNG diets compared with all others. Discussion: These data suggest that a qualitative change in dietary carbohydrate source modulates body weight and adiposity.     

Self‐Selected Macronutrient Diet Affects Energy and Glucose Metabolism in Brown Fat‐Ablated Mice

Objective: Obese transgenic UCP‐DTA mice have largely ablated brown adipose tissue and develop obesity and diabetes, which are highly susceptible to a high‐fat diet. We investigated macronutrient self‐selection and its effect on development of obesity, diabetes, and energy homeostasis in UCP‐DTA mice. Research Methods and Procedures: UCP‐DTA and wild‐type littermates were fed a semisynthetic macronutrient choice diet (CD) ad libitum from weaning until 17 weeks. Energy homeostasis was assessed by measurement of food intake, food digestibility, body composition, and energy expenditure. Diabetes was assessed by blood glucose measurements and insulin tolerance test. Results: Wild‐type and UCP‐DTA mice showed a high fat preference and increased energy digestion on CD compared with a low‐fat standard diet. On CD, wild‐type mice accumulated less body fat (16.9%) than UCP‐DTA (32.6%) mice, although they had a higher overall energy intake. Compared with wild‐type mice, resting metabolic rate was reduced in UCP‐DTA mice irrespective of diet. UCP‐DTA mice progressively decreased their carbohydrate intake, resulting in an almost complete avoidance of carbohydrate. UCP‐DTA mice developed severe insulin resistance but showed decreased fed and fasted blood glucose on CD. Discussion: In contrast to wild‐type mice, UCP‐DTA mice were not able to reduce their weight gain efficiency on CD. This suggests that, because of the high fat preference of the background strain and the increased metabolic efficiency, brown adipose tissue‐deficient mice still develop obesity and insulin resistance on a macronutrient CD even when decreasing overall energy intake. Through the avoidance of carbohydrates, however, they are able to maintain normoglycemia.     

15N-Harnstoffumsatz bei Schafen nach Verabreichung in gelöster Form

Two slaughter experiments were carried out to determine whether the protein content of the diet has an influence upon the efficiency of utilization of ME in fast growing chickens. A normal‐protein diet (NPD, 204 g CP/kg DM; 14.7 MJ ME/kg DM) based on soybean meal as the sole source of protein was given at four different levels of intake (ad libitum or restricted at about 90, 65 and 40% ad lib) to 10‐d‐old animals for 2 weeks. In a parallel experiment the chickens were fed ad libitum a low protein diet (LPD, 66 g CP/kg DM; 15.0 MJ ME/kg DM) based on soybean meal. The intake of metabolizable energy ranged from 1675 to 777 and 1770 to 832 kJ/kgW^0.75 per day for NPD and LPD treatments, respectively. Mean values of energy retention, gross efficiency of energy utilization and energy retained as protein were significantly (P<. 05) lower and heat production (expressed as both kJ/kgW^0.75 per day and kJ/kg body protein content^0.75 per day) was significantly higher (P < .05) for the chickens fed on LPD. These findings support the concept of dietary‐induced thermogenesis in response to reductions in dietary protein concentration. It is concluded that the increased heat production found in the birds fed on the low‐protein diet can be explained by both an increase in energy requirements for maintenance (ME_m) and a sharp decrease in the efficiency of utilization of ME for growth (k₈).     

The Efficacy of Dietary Fat Vs. Total Energy Restriction for Weight Loss

Objective : Dietary fat restriction is currently being promoted as a weight loss strategy. However, previous investigations suggest that fat restriction alone may not be more beneficial than total energy restriction for the treatment of obesity. The purpose of this project was to assess whether an energy-restricted or fat-restricted diet was more effective at promoting weight loss, improving eating behaviors, and reducing barriers to dietary adherence. Research Methods and Procedures : Eighty individuals (15 men and 65 women) were randomized into the two treatment conditions. Subjects were 120% to 140% of ideal body weight and 25 years to 45 years old. Treatment consisted of 24 weeks of dietary fat (22 g/day to 26 g/day) or energy restriction (4,186 kJ/day to 5,023 kJ/day), including behavior modification and exercise. Body weight change, dietary intake, eating behaviors, and barriers to adherence were measured at baseline and after treatment. Results : Results show that subjects in the energy-restricted condition lost over twice as much weight as those in the fat-restricted group (11.5 kg vs. 5.2 kg). Additionally, subjects in the low-energy condition had greater improvements in eating behavior scores, enhanced feelings of wellness, a greater distaste for dietary fat, and no more pronounced feelings of deprivation than did those in the fat-restricted condition. Discussion : An energy-restricted diet produces greater short-term weight loss than dietary fat restriction without many of the negative consequences commonly attributed to reducing energy intake.     

Caloric midpoint is associated with total calorie and macronutrient intake and body mass index in undergraduate students

ABSTRACT

Studies have suggested that eating at later times may be a risk factor for being overweight. The aim of this study was to investigate the association of caloric midpoint on the anthropometric profile and calorie and macronutrient intake during the day. The study included 718 Brazilian undergraduate students (20.5 ± 2.9 years old; 67% women). Dietary intake was assessed by 24-h recall and the diurnal variation of calorie consumption was evaluated by caloric midpoint average time at which 50% of daily energy were consumed. Participants were classified into two groups according to caloric midpoint median; early eaters (caloric midpoint ≤ 3:00 pm) or late eaters (caloric midpoint > 3:00 pm). Body weight and waist circumference were measured and body mass index (BMI) was determined. Generalized linear models adjusted for confounding variables were used to determine the association between variables. The late eaters presented higher BMI when compared to early eaters (23.0 kg/m² ± 0.3 vs. 22.1 kg/m² ± 0.2, respectively; p = .02). Late eaters reported a higher total daily consumption of energy (p < .001) and proportion consumed after 9:00 pm (p < .001), as well as total daily carbohydrate (p < .001), protein (p < .001), fat (p < .001), saturated fat (p < .001), and cholesterol (p = .04) intake when compared with early eaters. We conclude that concentrating food intake later in the day is associated with higher total energy and macronutrient intake as well as a higher average BMI.