No abstract

Obese individuals have an increased preference for high caloric foods, such as sweets and fats. However, following gastric bypass (GBP) surgery, morbidly obese patients tend to avoid these foods. We hypothesize that this aversion may occur, in part, from permutations in taste acuity. To test this hypothesis, taste detection and recognition thresholds for the four basic tastes (salt, sweet, sour, and bitter) were assessed using a modification of the Henkin forced choice three stimulus technique. Taste acuity measurements were obtained at baseline and at 30, 60, and 90 days post-operative for six morbidly obese GBP women and ten non-surgical, lean female controls. We found nonsignificant differences in taste detection and recognition thresholds between morbidly obese and lean control study subjects at baseline, and no significant correlation between taste acuity and body size. Furthermore, in our study population of lean and obese women, ages 26 to 52, there were no significant interrelationships between baseline taste thresholds and known effectors of taste acuity, i.e., zinc levels, glycemic status, liver and kidney function, or age. Following GBP surgery, a significant up-regulation in taste acuity for bitter and sour was observed along with a trend toward a reduction in salt and sweet detection and recognition thresholds. These findings would suggest the following: (1) taste acuity does not influence taste preferences of the obese individual who has not had bariatric surgery; (2) taste effectors such as zinc, when within the range of normal values, do not alter thresholds of the 4 basic tastes; and (3) weight loss following gastric bypass surgery is associated with an up-regulation in taste acuity in the morbidly obese. Studies are currently under investigation at our center to identify the specific etiology of taste acuity upregulation in the morbidly obese following GBP surgery.

Bariatric surgery, a highly successful treatment for obesity, requires adherence to special dietary recommendations to insure the achievement of weight loss goals and weight maintenance. Postoperative consumption of protein is linked to satiety induction, nutritional status, and weight loss. Hence, we conducted an extensive literature review to identify studies focused on the following: protein and nutritional status; recommendations for dietary protein intake; the effects of protein-rich diets; and associations between dietary protein intake and satiety, weight loss, and body composition. We found that there have been few studies on protein intake recommendations for bariatric patients. Dietary protein ingestion among this population tends to be inadequate, potentially leading to a loss of lean body mass, reduced metabolic rates, and physiological damage. Conversely, a protein-rich diet can lead to increased satiety, enhanced weight loss, and improved body composition. The quality and composition of protein sources are also very important, particularly with respect to the quantity of leucine, which helps to maintain muscle mass, and thus is particularly important for this patient group. Randomized studies among bariatric surgery patient populations are necessary to establish the exact quantity of protein that should be prescribed to maintain their nutritional status.

Although vitamin D deficiency has been well-documented following gastric bypass surgery, there are few studies of vitamin D status in the non-operative morbidly obese patient. We examined 25-hydroxyvitamin D (25-OHD) levels in 60 morbidly obese pre-operative females; 62% of them had 25-OHD levels below normal range (16-74 ng/ml) which were not associated with reductions in serum calcium or phosphorus, liver or kidney dysfunction, and were not significantly correlated to patients' age. However, 25-OHD levels were significantly (p < 0.0001) and negatively correlated to body mass (r = -0.49). These data suggest that low vitamin D may be associated with obesity per se. Hypovitaminosis D, when it is found in post-bariatric surgery patients, may not be caused by the surgery since it may have been present to some degree pre-operatively.

We evaluated the insulin response to a standard oral glucose tolerance test (OGTT) and in vitro insulin binding to erythrocytes (RBC) in 26 women from 3 groups: Group NW, normal women (n = 11); Group DS, women (n = 9) with elevated serum DHEAS concentrations, greater than 400 micrograms/dl (greater than 10.84 mumol/L); and Group IR, women (n = 6) with elevated basal plasma insulin concentrations (IRI). There was a significant linear correlation between the area under the insulin response curve (IRI-AUC) and serum testosterone (T) (r = 0.78, p = 0.0001). Using stepwise multiple linear regression, IRI-AUC was characterized as a function of both serum T and DHEAS; positively with T and negatively with DHEAS. In vitro (n = 17), there was a positive correlation between RBC-insulin binding and serum DHEAS (r = 0.54, p = 0.029) and a negative correlation between RBC-binding and T (r = -0.57, p = 0.017). We conclude that DHEAS may enhance insulin binding and action and that DHEAS and T have divergent functional relationships with IRI. DHEAS and T may therefore exert opposing effects on insulin secretion and action.

PURPOSE:Hyperinsulinemia is a common feature of many obesity syndromes. We investigated whether suppression of insulin secretion, without dietary or exercise intervention, could promote weight loss and alter food intake and preference in obese adults. METHODS: Suppression of insulin secretion was achieved using octreotide-LAR 40 mg IM q28d for 24 weeks in 44 severely obese adults (89% female, 39% minority). Oral glucose tolerance testing was performed before and after treatment, indices of b-cell activity (CIRgp), insulin sensitivity (CISI), and clearance (CP/I AUC) were computed, and leptin levels, 3-day food records and carbohydrate-craving measurements were obtained. DEXA evaluations were performed pre-and post-therapy in an evaluable subgroup. RESULTS: For the entire cohort, significant insulin suppression was achieved with simultaneous improvements in insulin sensitivity, weight loss, and body mass index (BMI). Leptin, fat mass, total caloric intake, and carbohydrate craving significantly decreased. When grouped by BMI response, high responders (HR; DBMIoÀ3 kg/m 2 ) and low responders (LR; DBMI between À3 and À0.5) exhibited higher suppression of CIRgp and IAUC than nonresponders (NR; DBMI > À0.5). CISI improved and significant declines in leptin and fat mass occurred only in HR and LR. Conversely, both leptin and fat mass increased in NR. Carbohydrate intake was markedly suppressed in HR only, while carbohydrate-craving scores decreased in HR and LR. For the entire cohort, DBMI correlated with DCISI, Dfat mass, and Dleptin. DFat mass also correlated with DIAUC and DCISI. CONCLUSIONS: In a subcohort of obese adults, suppression of insulin secretion was associated with loss of body weight and fat mass and with concomitant modulation of caloric intake and macronutrient preference.

The morbidly obese have a disproportionately greater risk of hypertension, diabetes, and coronary artery disease than their lean or less seriously obese counterparts. Roux-en-Y gastric bypass surgery has been found to be highly effective in inducing, and sustaining, weight loss in individuals with morbid obesity. The purpose of the present study was to examine the effects of weight loss with Roux-en-Y gastric bypass surgery (GBP) on blood pressure, fasting blood glucose, and the lipid/lipoprotein status of 61 morbidly obese women and 21 men. Anthropometric and blood pressure assessments and blood samples for glucose and lipid/lipoprotein analyses were obtained before surgery and at 6 to 12 months postoperatively. By this time, morbidly obese (MO) males and females had lost 33% and 30% of their initial body weight, respectively, along with significant reductions in fasting blood glucose (p < 0.01) and systemic blood pressure (p < 0.05). Weight loss with GBP was also associated with significant reductions in the apoprotein B-containing lipoproteins and the triglyceride and cholesterol composition of these particles. There was a trend (p < 0.10) toward increased serum levels of high density lipoprotein (HDL)-cholesterol following GBP, and significant (p < 0.05) improvement in HDL subfraction distribution and composition. These findings demonstrate the effectiveness of GBP in inducing metabolic changes in the MO population, which may reduce the risk of coronary artery disease, diabetes, and hypertension.

Individuals with extreme obesity, compared to the nonobese, obtain less sleep and experience poorer sleep quality. Bariatric surgery improves sleep duration and quality.