Richard I. Stein

Weight and Metabolic Outcomes After 2 Years on a Low-Carbohydrate Versus Low-Fat Diet: A Randomized Trial

BACKGROUND Previous studies comparing low-carbohydrate and low-fat diets have not included a comprehensive behavioral treatment, resulting in suboptimal weight loss. OBJECTIVE To evaluate the effects of 2-year treatment with a low-carbohydrate or low-fat diet, each of which was combined with a comprehensive lifestyle modification program. DESIGN Randomized parallel-group trial. (ClinicalTrials.gov registration number: NCT00143936) SETTING 3 academic medical centers. PATIENTS 307 participants with a mean age of 45.5 years (SD, 9.7 years) and mean body mass index of 36.1 kg/m(2) (SD, 3.5 kg/m(2)). INTERVENTION A low-carbohydrate diet, which consisted of limited carbohydrate intake (20 g/d for 3 months) in the form of low-glycemic index vegetables with unrestricted consumption of fat and protein. After 3 months, participants in the low-carbohydrate diet group increased their carbohydrate intake (5 g/d per wk) until a stable and desired weight was achieved. A low-fat diet consisted of limited energy intake (1200 to 1800 kcal/d; <or=30% calories from fat). Both diets were combined with comprehensive behavioral treatment. MEASUREMENTS Weight at 2 years was the primary outcome. Secondary measures included weight at 3, 6, and 12 months and serum lipid concentrations, blood pressure, urinary ketones, symptoms, bone mineral density, and body composition throughout the study. RESULTS Weight loss was approximately 11 kg (11%) at 1 year and 7 kg (7%) at 2 years. There were no differences in weight, body composition, or bone mineral density between the groups at any time point. During the first 6 months, the low-carbohydrate diet group had greater reductions in diastolic blood pressure, triglyceride levels, and very-low-density lipoprotein cholesterol levels, lesser reductions in low-density lipoprotein cholesterol levels, and more adverse symptoms than did the low-fat diet group. The low-carbohydrate diet group had greater increases in high-density lipoprotein cholesterol levels at all time points, approximating a 23% increase at 2 years. LIMITATION Intensive behavioral treatment was provided, patients with dyslipidemia and diabetes were excluded, and attrition at 2 years was high. CONCLUSION Successful weight loss can be achieved with either a low-fat or low-carbohydrate diet when coupled with behavioral treatment. A low-carbohydrate diet is associated with favorable changes in cardiovascular disease risk factors at 2 years. PRIMARY FUNDING SOURCE National Institutes of Health.

Effect of Moderate Diet-Induced Weight Loss and Weight Regain on Cardiovascular Structure and Function

OBJECTIVES The objective of this prospective, single-site, 2-year dietary intervention study was to evaluate the effects of moderate weight reduction and subsequent partial weight regain on cardiovascular structure and function. BACKGROUND Obesity is associated with adverse cardiac and vascular structural and functional alterations. METHODS Sixty obese subjects (age 46 + or - 10 years, body mass index 37 + or - 3 kg/m(2)) were evaluated during their participation in a weight loss study. Cardiac and vascular ultrasound studies were performed at baseline and at 3, 6, 12, and 24 months after start of intervention. RESULTS Forty-seven subjects (78%) completed the entire 2-year follow-up. Average weight loss was 7.3 + or - 4.0%, 9.2 + or - 5.6%, 7.8 + or - 6.6%, and 3.8 + or - 7.9% at 3, 6, 12, and 24 months, respectively. Age- and sex-adjusted mixed linear models revealed that the follow-up time was significantly associated with decreases in weight (p < 0.0001), left ventricular (LV) mass (p = 0.001), and carotid intima-media thickness (p < 0.0001); there was also significant improvement in LV diastolic (p < or = 0.0001) and systolic (p = 0.001) function. Partial weight regain diminished the maximal observed beneficial effects of weight loss, however cardiovascular parameters measured at 2 years still showed a net benefit compared with baseline. CONCLUSIONS Diet-induced moderate weight loss in obese subjects is associated with beneficial changes in cardiovascular structure and function. Subsequent weight regain is associated with partial loss of these beneficial effects. (The Safety and Effectiveness of Low and High Carbohydrate Diets; NCT00079547).

Behavioral Economic Predictors of Overweight Children's Weight Loss

OBJECTIVE Our goal was to determine whether behavioral economic constructs-including impulsivity (i.e., steep discounting of delayed food and monetary rewards), the relative reinforcing value of food (RRVfood), and environmental enrichment (i.e., the presence of alternatives to unhealthy foods in the home and neighborhood environments)-are significant pretreatment predictors of overweight childrens weight loss within family-based treatment. METHOD Overweight children (N = 241; ages 7-12 years; 63% female; 65% non-Hispanic White) enrolled in a 16-week family-based obesity treatment with at least one parent. At baseline, children completed a task to assess RRVfood and delay discounting measures of snack foods and money to assess impulsivity. Parents completed questionnaires to assess environmental enrichment. RESULTS Children who found food highly reinforcing and steeply discounted future food rewards at baseline showed a blunted response to treatment compared with children without this combination of risk factors. High environmental enrichment was associated with treatment success only among children who did not find food highly reinforcing. Monetary discounting rate predicted weight loss, regardless of childrens level of RRVfood. CONCLUSIONS Investigation is warranted into novel approaches to obesity treatment that target underlying impulsivity and RRVfood. Enriching the environment with alternatives to unhealthy eating may facilitate weight loss, especially for children with low RRVfood.

Aspiration Therapy Leads to Weight Loss in Obese Subjects: A Pilot Study

BACKGROUND & AIMS Obese patients rarely achieve long-term weight loss with only lifestyle interventions. We evaluated the use of endoscopic aspiration therapy for obesity. Aspiration therapy involves endoscopic placement of a gastrostomy tube (A-Tube) and the AspireAssist siphon assembly (Aspire Bariatrics, King of Prussia, PA) to aspirate gastric contents 20 minutes after meal consumption. METHODS We performed a pilot study of 18 obese subjects who were randomly assigned (2:1) to groups that underwent aspiration therapy for 1 year plus lifestyle therapy (n = 11; mean body mass index, 42.6 ± 1.4 kg/m(2)) or lifestyle therapy only (n = 7; mean body mass index, 43.4 ± 2.0 kg/m(2)). Lifestyle intervention comprised a 15-session diet and behavioral education program. RESULTS Ten of the 11 subjects who underwent aspiration therapy and 4 of the 7 subjects who underwent lifestyle therapy completed the first year of the study. After 1 year, subjects in the aspiration therapy group lost 18.6% ± 2.3% of their body weight (49.0% ± 7.7% of excess weight loss [EWL]) and those in the lifestyle therapy group lost 5.9% ± 5.0% (14.9% ± 12.2% of EWL) (P < .04). Seven of the 10 subjects in the aspiration therapy group completed an additional year of therapy and maintained a 20.1% ± 3.5% body weight loss (54.6% ± 12.0% of EWL). There were no adverse effects of aspiration therapy on eating behavior and no evidence of compensation for aspirated calories with increased food intake. No episodes of binge eating in the aspiration therapy group or serious adverse were reported. CONCLUSIONS In a pilot study, aspiration therapy appears to be a safe and effective long-term weight loss therapy for obesity.

Long-term efficacy of psychological treatments for binge eating disorder

BACKGROUND The long-term efficacy of psychological treatments for binge eating disorder remains largely unknown. AIMS To examine the long-term efficacy of out-patient group cognitive-behavioural therapy (CBT) and group interpersonal psychotherapy (IPT) for binge eating disorder and to analyse predictors of long-term non-response. METHOD Ninety people with binge eating disorder were assessed 4 years after treatment cessation within a randomised trial (trial registration: NCT01208272). RESULTS Participants showed substantial long-term recovery, partial remission, clinically significant improvement and significant reductions in associated psychopathology, despite relapse tendencies in single secondary outcomes. Body mass index remained stable. While the IPT group demonstrated an improvement in eating disorder symptoms over the follow-up period, the CBT group reported a worsening of symptoms, but treatments did not differ at any time point. CONCLUSIONS The results document the long-term efficacy of out-patient CBT and IPT for binge eating disorder. Further research is warranted to elucidate the time course and mechanisms of change of these treatments for binge eating disorder.

Pretreatment and process predictors of outcome in interpersonal and cognitive behavioral psychotherapy for binge eating disorder.

The present study examined pretreatment and process predictors of individual nonresponse to psychological group treatment of binge eating disorder (BED). In a randomized trial, 162 overweight patients with BED were treated with either group cognitive-behavioral therapy or group interpersonal psychotherapy. Treatment nonresponse, which was defined as nonabstinence from binge eating, was assessed at posttreatment and at 1 year following treatment completion. Using 4 signal detection analyses, greater extent of interpersonal problems prior to treatment or at midtreatment were identified as predictors of nonresponse, both at posttreatment and at 1-year follow-up. Greater pretreatment and midtreatment concerns about shape and weight, among those patients with low interpersonal problems, were predictive of posttreatment nonresponse. Lower group cohesion during the early treatment phase predicted nonresponse at 1-year follow-up. Attention to specific pre- or intreatment predictors could allow for targeted selection into differential or augmented care and could thus improve response to group psychotherapy for BED.

Weight Loss Reduces Liver Fat and Improves Hepatic and Skeletal Muscle Insulin Sensitivity in Obese Adolescents

Obesity in adolescents is associated with metabolic risk factors for type 2 diabetes, particularly insulin resistance and excessive accumulation of intrahepatic triglyceride (IHTG). The purpose of this study was to evaluate the effect of moderate weight loss on IHTG content and insulin sensitivity in obese adolescents who had normal oral glucose tolerance. Insulin sensitivity, assessed by using the hyperinsulinemic–euglycemic clamp technique in conjunction with stable isotopically labeled tracer infusion, and IHTG content, assessed by using magnetic resonance spectroscopy, were evaluated in eight obese adolescents (BMI ≥95th percentile for age and sex; age 15.3 ± 0.6 years) before and after moderate diet‐induced weight loss (8.2 ± 2.0% of initial body weight). Weight loss caused a 61.6 ± 8.5% decrease in IHTG content (P = 0.01), and improved both hepatic (56 ± 18% increase in hepatic insulin sensitivity index, P = 0.01) and skeletal muscle (97 ± 45% increase in insulin‐mediated glucose disposal, P = 0.01) insulin sensitivity. Moderate diet‐induced weight loss decreases IHTG content and improves insulin sensitivity in the liver and skeletal muscle in obese adolescents who have normal glucose tolerance. These results support the benefits of weight loss therapy in obese adolescents who do not have evidence of obesity‐related metabolic complications during a standard medical evaluation.

Comparative Effects of Low-Carbohydrate High-Protein Versus Low-Fat Diets on the Kidney

BACKGROUND AND OBJECTIVES Concerns exist about deleterious renal effects of low-carbohydrate high-protein weight loss diets. This issue was addressed in a secondary analysis of a parallel randomized, controlled long-term trial. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS Between 2003 and 2007, 307 obese adults without serious medical illnesses at three United States academic centers were randomly assigned to a low-carbohydrate high-protein or a low-fat weight-loss diet for 24 months. Main outcomes included renal filtration (GFR) indices (serum creatinine, cystatin C, creatinine clearance); 24-hour urinary volume; albumin; calcium excretion; and serum solutes at 3, 12, and 24 months. RESULTS Compared with the low-fat diet, low-carbohydrate high-protein consumption was associated with minor reductions in serum creatinine (relative difference, -4.2%) and cystatin C (-8.4%) at 3 months and relative increases in creatinine clearance at 3 (15.8 ml/min) and 12 (20.8 ml/min) months; serum urea at 3 (14.4%), 12 (9.0%), and 24 (8.2%) months; and 24-hour urinary volume at 12 (438 ml) and 24 (268 ml) months. Urinary calcium excretion increased at 3 (36.1%) and 12 (35.7%) months without changes in bone density or clinical presentations of new kidney stones. CONCLUSIONS In healthy obese individuals, a low-carbohydrate high-protein weight-loss diet over 2 years was not associated with noticeably harmful effects on GFR, albuminuria, or fluid and electrolyte balance compared with a low-fat diet. Further follow-up is needed to determine even longer-term effects on kidney function.

Bariatric surgery-induced weight loss causes remission of food addiction in extreme obesity

To test the hypotheses that bariatric surgery‐induced weight loss: induces remission of food addiction (FA), and normalizes other eating behaviors associated with FA.

Weight and Metabolic Outcomes After 2 Years on a Low- Carbohydrate Versus Low-Fat Diet:

Previous studies have demonstrated that low-carbohydrate diets achieve greater short-term (6 months) weight loss than low-fat diets. Longer-term (1 to 2 years) data have been inconsistent. Weight loss obtained with either diet is generally minimal. Some investigators have attributed this suboptimal weight loss to the uniform lack of inclusion in most studies of behavioral interventions to change lifestyle. This randomized, parallel-group, controlled trial compared the effects of 2-year treatment with either a low-carbohydrate or low-fat diet combined with a behavioral intervention program on body weight and several other clinical endpoints. Between 2003 and 2007, 307 adults at a mean age of 45.5 years (SD, 9.7 years) and mean body mass index of 36.1 kg/m 2 (SD, 3.5 kg/m 2 ) were enrolled. A total of 153 of the study subjects (group 1) were assigned to a low-carbohydrate diet, which limited carbohydrate intake to 20 g/d for 3 months; unrestricted consumption of fat and protein was allowed. Carbohydrate intake after the first 12 weeks was gradually increased (5 g/d per week) until the desired weight was reached. Group 2 was comprised of 154 participants who were assigned to receive a low-fat diet limiting energy intake to 1200 to 1800 kcal/d, with ≤30% of the calories from fat. All participants received comprehensive behavioral treatment. Weight loss and most secondary outcomes (serum lipoproteins, blood pressure, urinary ketones, and symptoms were assessed at 3, 6, 12, and 24 months. Secondary outcomes of bone mineral density and body composition were evaluated at 6, 12, and 24 months. Both diet groups achieved clinically significant and almost identical weight loss at 1 year (11 kg [11%]) and at 2 years (7 kg [7%]. No differences were found between the groups in weight, bone mineral density, or body composition over the 2 years of the study. At 3 and 6 months, however, significantly greater reductions were found in the low-carbohydrate diet group than in the low-fat diet group for triglyceride levels, diastolic pressure, and very-low-density as well as low-density lipoprotein cholesterol levels. More adverse symptoms were observed in the first 6 months in the low-carbohydrate diet group. An increase of approximately 20% in high-density lipoprotein cholesterol levels was observed in the low-carbohydrate diet group at 6 months and persisted throughout the study; this increase was more than twice that found in the low-fat diet group. The investigators conclude from these findings that either a low-carbohydrate or a low-fat diet can achieve successful long-term weight loss if combined with a behavioral intervention program.