How effective are meal replacements for treating obesity?

Background - Effective weight loss strategies are needed to reduce cardiovascular disease risk. Meal replacements as a weight loss strategy are widely used in the community however it is not known how effective they are outside a controlled clinical trial environment. Objective - To compare the use of meal replacements (MR) twice a day with a structured low fat (C) weight loss diet on weight, lipids, inflammatory and thrombotic markers and vascular physiology. Design - Randomised, parallel design in overweight volunteers with a triglyceride >2 mmol/L. Outcomes - Fifty-five subjects completed 3 and 6 months. After 3 months weight loss (Mean +/- SEM) was 6.0 +/- 4.2 kg (MR) and 6.6 +/- 3.4 kg (C group) (P< 0.001) with no differences between the groups. At 6 months weight loss was 9.0 +/- 6.9kg (MR) and 9.2 +/- 5.1kg (C). At 12 weeks triglycerides fell significantly in C (0.48 mmol/L or 25%) but not in MR (4%) (P< 0.05 between diets). There was no difference at 6 months. Inflammatory markers at 6 months: CRP decreased by 20% (P< 0.02) in MR with no change in C (P=0.002 between diets), no change in IL6 was noted. Fibrinolytic factors at 6 months: tPA fell in both groups by 20-26% (P< 0.001), PAI-1 fell only in the C group 28% (P=0.001), [P=0.025 between diets]. Adhesion molecules at 6 months: sICAM1 fell by 10% in both groups (P< 0.001), no changes in sVCAM1. Flow mediated dilatation did not change in either group but pulse wave velocity improved from 7.52+/- 2.49 m/s to 6.25 +/-1.58 in MR (P< 0.05). The change in C was similar 7.41 +/- 3.22 to 6.32 +/- 1.38 m/sec but was not significant because of greater baseline variation. Conclusions - Meal replacements are as effective as a structured low fat weight diet for weight loss which is maintained to 6 months. weight loss is associated with lower triglyceride, circulating adhesion molecules and pulse wave velocity.

Self-help and long-term behavior therapy for obesity.

The Trevose Behavior Modification Program, a self-help group offering continuing care for obesity, has recently been shown to produce large long-term weight losses. The present study aimed to replicate this finding across different settings and participants, assessing the weight losses and attrition rates of 128 participants in three Trevose program satellite groups that used the same treatment procedures and manual as the central Trevose group. The satellite groups' results closely paralleled those of the Central Group. Mean intent-to-treat weight loss, or final losses recorded for all participants regardless of their treatment termination date, was 13.7 +/- 0.7% of initial body weight (1.8 +/- 0.7 kg). At two years, 43.8% of participants remained in treatment, having lost a mean of 19.0 +/- 0.8% of their body weight (16.2 +/- 1.0 kg); at five years, 23.4% remained, having lost 18.4 +/- 1.1% of body weight (15.6 +/- 1.5 kg). These results demonstrate that the Trevose model of weight control, combining self-help and continuing care, can be extended and disseminated to other settings, with potentially significant public health consequences.

Pre-operative predictors of weight loss at 1-year after Lap-Band surgery.

BACKGROUND: The authors studied a range of preoperative factors for their predictive value of effectiveness of Lap-Band placement, using the percentage of excess weight loss at 1-year as the outcome measure (%EWL1). METHODS: All factors were measured and recorded prior to surgery. Factors included: patient demographics, family, medical and weight history. Laboratory measures and the responses to the SF-36 Health Survey were also assessed. Factors were assessed for correlation with %EWL1. RESULTS: The group (N=440, F:M 383:57) had mean age 40.0+/-9.5 years, weight of 126+/-25 kg, and BMI 45.6+/-7.5 kg/m2 pre-operatively. At 1-year follow-up, the group had mean weight 97.6< or =20 kg, BMI 35.6 = 6.3 kg/m2, and %EWL1 45.8< or =17%. Increasing age (R= -0.13, p<0.01) and preoperative BMI (R=-0.22, p<0.001) were significantly associated with less %EWL1 and all other factors were controlled for these before assessing significance. Important factors associated with a lower %EWL1 included: hyperinsulinemia (R=-0.36, p<0.001), insulin resistance (R=-0.33, p<0.001) and disease associated with insulin resistance, poor physical ability, pain, and poor general health responses to the SF-36 Health Survey. Patients who consumed alcohol regularly had a better rate of weight loss (R= 0.23, p<0.005). Factors that had no influence included gender, a history of mental illness and measures of mental health, previous bariatric surgery, and a history of many medical conditions associated with obesity. CONCLUSION: Important physical factors have been found to influence the rate of weight loss. Those with increased age, pain, physical disability and insulin resistance have a great deal to gain from weight loss. Although this study has identified factors that are associated with less weight loss, we have not found any factor that predicts an unacceptably low weight loss and thus provides a contraindication to Lap-Band placement. The findings of this study allow us to set more realistic goals for the rate of weight loss in specified sub-groups of our patients.

Weight Loss-associated changes in acute effects of nateglinide on insulin secretion after glucose loading: results of glucose loading on 2 consecutive days.

AIM: The aim of this study was to investigate the influence of changes in insulin resistance and early insulin secretion on the insulin secretagogic effects of nateglinide. METHODS: Oral glucose tolerance testing (OGTT, 75 g) was performed in obese patients before and after weight loss on 2 consecutive days (first day OGTT without nateglinide, second day OGTT with nateglinide), to compare any weight loss associated changes in the nateglinide-induced insulin response to glucose loading. RESULTS: Reductions in visceral fat, liver fat, skeletal muscle fat and homeostasis model assessment (HOMA)-R due to weight loss were associated with increased Delta insulin 30 min/Delta glucose 30 min (DeltaI30/DeltaG30), and reduced area under the curve (AUC) for plasma glucose as seen in OGTT results. Results from OGTT showed that nateglinide administration was associated with reductions in plasma glucose AUC, both before and after weight loss. Before weight loss, although there was a significant elevation of DeltaI30/DeltaG30 associated with nateglinide treatment, no major change in the insulin-secreting dynamics after glucose loading was observed. After weight loss, nateglinide administration produced a significant increase in DeltaI30/DeltaG30, with insulin secretion peaking more quickly. CONCLUSION: Insulin response to nateglinide after glucose loading varied greatly in conjunction with weight loss. This may be accounted for not only by the enhancement of early insulin response to nateglinide associated with the improvement of early insulin response with weight loss but also by the reduced visceral fat, which in turn led to reduced levels of free fatty acids in portal blood and hepatic triglycerides, as well as increased hepatic insulin clearance.

Pork quality, processing, and sensory characteristics of dry-cured hams as influenced by Duroc crossing and sex.

This study was designed to evaluate Duroc (DU) crossing for Carso dry-cured ham production. One hundred fifty-four pigs (81 females and 73 castrates) of four different genotypes, pure Landrace pigs (LAN), offspring of LAN females crossed with Large White (LW) males (LWxLAN), offspring of LAN females crossed with DU males (DUxLAN), and offspring of LWxLAN females crossed with DU males (DUx[LWxLAN]), were chosen in the weight range of 105 to 120 kg (112.7 +/- 0.4 kg). Raw material quality was evaluated for ham fatness (intra- and intermuscular and subcutaneous) and meat quality (pH, color, water-holding capacity) of longissimus dorsi, biceps femoris, and semimembranosus muscles. Ham weight losses were recorded at different stages of processing. The biceps femoris and semimembranosus muscles were analyzed for chemical composition before (lipid, moisture, total nitrogen, nonprotein nitrogen) and after (moisture, salt, total nitrogen, nonprotein nitrogen) processing. Chemical and sensory analyses were performed on 96 dry hams (12 castrates and 12 females per genotype). Biceps femoris and semimembranosus muscles were evaluated for color, saltiness, aroma, and texture. Pigs of the four genotypes had similar ham fatness as estimated by subcutaneous fat thickness. Duroc crosses exhibited higher intramuscular fat content, marbling, and intermuscular fat. Crossing with DU resulted in lower weight losses during ham processing. Castrates were fatter and had more intra- and intermuscular fat and lower ham processing weight losses than females. A strong negative relationship between ham fatness and ham processing losses was observed. Chemical and sensory traits of dry ham muscles were little affected by DU crossing. Lower salt content of biceps femoris was found in DU crosses. Dry hams from female pigs had higher total and nonprotein nitrogen, but drier, firmer texture and higher resistance to cutting force compared to dry hams from castrated pigs. Crossing with DU demonstrated some disadvantages (more intermuscular fat, more slice visible fat) and advantages (lower weight loss and salt intake) for the quality of dry-cured ham.

Attenuation of proteasome-induced proteolysis in skeletal muscle by {beta}-hydroxy-{beta}-methylbutyrate in cancer-induced muscle loss.

Loss of skeletal muscle is an important determinant of survival in patients with cancer-induced weight loss. The effect of the leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) on the reduction of body weight loss and protein degradation in the MAC16 model of cancer-induced weight loss has been compared with that of eicosapentaenoic acid (EPA), a recognized inhibitor of protein degradation. HMB was found to attenuate the development of weight loss at a dose greater than 0.125 g/kg accompanied by a small reduction in tumor growth rate. When EPA was used at a suboptimal dose level (0.6 g/kg) the combination with HMB seemed to enhance the anticachectic effect. Both treatments caused an increase in the wet weight of soleus muscle and a reduction in protein degradation, although there did not seem to be a synergistic effect of the combination. Proteasome activity, determined by the "chymotrypsin-like" enzyme activity, was attenuated by both HMB and EPA. Protein expression of the 20S alpha or beta subunits was reduced by at least 50%, as were the ATPase subunits MSS1 and p42 of the 19S proteasome regulatory subunit. This was accompanied by a reduction in the expression of E2(14k) ubiquitin-conjugating enzyme. The combination of EPA and HMB was at least as effective or more effective than either treatment alone. Attenuation of proteasome expression was reflected as a reduction in protein degradation in gastrocnemius muscle of cachectic mice treated with HMB. In addition, HMB produced a significant stimulation of protein synthesis in skeletal muscle. These results suggest that HMB preserves lean body mass and attenuates protein degradation through down-regulation of the increased expression of key regulatory components of the ubiquitin-proteasome proteolytic pathway, together with stimulation of protein synthesis.

Relationship between sympathetic reactivity and body weight loss in morbidly obese subjects.

OBJECTIVE: To investigate the possible role of peripheral sympathetic activity in gastric bypass-induced body weight loss. SUBJECTS AND METHODS: In 42 morbidly obese patients (sex: 36 f/6 m; BMI: 46.0+/-0.7 kg/m(2)) undergoing a gastric bypass, the skin vasoconstrictor reflex in answer to a deep inspiration was measured by laser Doppler fluximetry. The extent of vasoconstriction, measured at the second finger of the left hand, was expressed as percent reduction of the basal blood flux (% vasoconstriction). Insulin sensitivity was assessed before surgery in a subset of patients (n=11), by the method of euglycemic, hyperinsulinemic clamp. Body weight and composition were evaluated before, and 3, 6 and 12 months after surgery. At the same time points, energy intake (kJ/day) was evaluated by means of both food record diary and alimentary anamnesis. RESULTS: The % vasoconstriction, which was significantly (P=0.01) greater in normoglycemic subjects than in diabetic ones, was also significantly (P=0.03) related to the extent of insulin sensitivity measured during the euglycemic clamp.The % vasoconstriction showed a significant (P>0.0001), positive correlation with weight reduction obtained between the 6th and 12th months following surgery; as a consequence, % vasoconstriction was significantly (P=0.0004) related to the overall body weight loss achieved during the year following the operation. These correlations remained significant in multiple regression analysis with adjustment for age, initial body weight, plasma glucose and insulin (P=0.0007 and 0.006, respectively). The % vasoconstriction was also significantly (P=0.0006), negatively related to energy intake measured 12 months after surgery. CONCLUSIONS: In conditions of stable body weight, the sympathetic nervous system (SNS) reactivity is influenced by the degree of insulin resistance. A high capacity to activate the SNS, measured before surgery, is associated with both a larger gastric bypass-induced weight loss and a lower energy intake, at the phase of weight stabilization.

Intentional weight loss and incidence of obesity-related cancers: the Iowa Women's Health Study.

OBJECTIVE: To examine the association of voluntary vs involuntary weight loss with incidence of cancer in older women. DESIGN: Prospective cohort study from 1993 to 2000, with cancer incidence identified through record linkage to a cancer registry. SUBJECTS: A total of 21,707 postmenopausal women initially free of cancer. MEASUREMENTS: Women completed a questionnaire about intentional and unintentional weight loss episodes of > or =20 pounds during adulthood. RESULTS: Compared with women who never had any > or =20 pounds weight loss episode, women who ever experienced intentional weight loss > or =20 pounds but no unintentional weight loss had incidence rates lower by 11% for any cancer (RR=0.89, 95% CI 0.79-1.00), by 19% for breast cancer (RR=0.81, 95% CI 0.66-1.00), by 9% for colon cancer (RR=0.91, 95% CI 0.66-1.24), by 4% for endometrial cancer (RR=0.96, 95% CI 0.61-1.52), and by 14% for all obesity-related cancer (RR=0.86, 95% CI 0.74-1.01) after adjusting for age, body mass index, waist-to-hip ratio, physical activity, education, marital status, smoking status, pack-years of cigarettes, current estrogen use, alcohol use, parity, and multivitamin use. Furthermore, although overweight women were at increased risk of several cancers, women who experienced intentional weight loss episodes of 20 or more pounds and were not currently overweight were observed to have an incidence of cancer similar to nonoverweight women who never lost weight. Unintentional weight loss episodes were not associated with decreased cancer risk. CONCLUSIONS: These findings suggest that intentional weight loss might reduce risk of obesity-related cancers.