Preventing sarcopenic obesity among breast cancer patients who receive adjuvant chemotherapy: results of a feasibility study

PURPOSE: Weight gain is a common side effect of adjuvant chemotherapy for breast cancer - a side effect that decreases quality of life and also may decrease both disease-free and overall survival. This weight gain also is unique, since patients lose lean body mass while they gain weight. These body composition changes become apparent within six months of diagnosis. METHODS: We explored whether a clinic-based exercise program, which promoted a specialized program of strength training, aerobic activity and a healthful (相似文献   

Reduced sympathetic nervous activity. A potential mechanism predisposing to body weight gain.

The sympathetic nervous system is recognized to play a role in the etiology of animal and possibly human obesity through its impact on energy expenditure and/or food intake. We, therefore, measured fasting muscle sympathetic nerve activity (MSNA) in the peroneal nerve and its relationship with energy expenditure and body composition in 25 relatively lean Pima Indian males (means +/- SD; 26 +/- 6 yr, 82 +/- 19 kg, 28 +/- 10% body fat) and 19 Caucasian males (29 +/- 5 yr, 81 +/- 13 kg, 24 +/- 9% body fat). 24-h energy expenditure, sleeping metabolic rate, and resting metabolic rate were measured in a respiratory chamber, whereas body composition was estimated by hydrodensitometry. Pima Indians had lower MSNA than Caucasians (23 +/- 6 vs 33 +/- 10 bursts/min, P = 0.0007). MSNA was significantly related to percent body fat in Caucasians (r = 0.55, P = 0.01) but not in Pimas. MSNA also correlated with energy expenditure adjusted for fat-free mass, fat mass, and age in Caucasians (r = 0.51, P = 0.03; r = 0.54, P = 0.02; and r = 0.53, P = 0.02 for adjusted 24-h energy expenditure, sleeping metabolic rate, and resting metabolic rate, respectively) but not in Pima Indians. In conclusion, the activity of the sympathetic nervous system is a determinant of energy expenditure in Caucasians. Individuals with low resting MSNA may be at risk for body weight gain resulting from a lower metabolic rate. A low resting MSNA and the lack of impact of MSNA on metabolic rate might play a role in the etiology of obesity in Pima Indians.     

Skeletal muscle metabolism is a major determinant of resting energy expenditure.

Energy expenditure varies among people, independent of body size and composition, and persons with a "low" metabolic rate seem to be at higher risk of gaining weight. To assess the importance of skeletal muscle metabolism as a determinant of metabolic rate, 24-h energy expenditure, basal metabolic rate (BMR), and sleeping metabolic rate (SMR) were measured by indirect calorimetry in 14 subjects (7 males, 7 females; 30 +/- 6 yr [mean +/- SD]; 79.1 +/- 17.3 kg; 22 +/- 7% body fat), and compared to forearm oxygen uptake. Values of energy expenditure were adjusted for individual differences in fat-free mass, fat mass, age, and sex. Adjusted BMR and SMR, expressed as deviations from predicted values, correlated with forearm resting oxygen uptake (ml O2/liter forearm) (r = 0.72, P less than 0.005 and r = 0.53, P = 0.05, respectively). These findings suggest that differences in resting muscle metabolism account for part of the variance in metabolic rate among individuals and may play a role in the pathogenesis of obesity.     

Patterns of weight and body composition change in premenopausal women with early stage breast cancer: has weight gain been overestimated?

The widely documented problem of weight gain during adjuvant breast cancer chemotherapy has decreased in frequency and magnitude. However, adverse changes in body composition remain a problem. This study identified the frequency, magnitude, and patterns of weight and body composition change in a sample of premenopausal breast cancer survivors who were receiving 3 common chemotherapy regimens. The longitudinal study followed 76 women at 2 centers in Ontario, Canada. Measures were obtained at baseline, the start of every other treatment cycle and treatment completion. Participants' mean age was 44.1 years (SD = 5.9). Their mean baseline weight and body mass index were 69.3 kg (SD = 17.0) and 26 kg/m2 (SD = 6.6), respectively. Fifty-five percent maintained stable weights, while 34% gained and 10.5% lost weight. Their mean weight change during treatment was a 1.4-kg gain. Weight gainers and losers gained or lost 3 to 4 times as much fat as fat-free mass, respectively. A researcher's definition of "weight change" will influence the amount of weight gain reported, and the results of this study suggest that previous research may have overestimated the frequency and magnitude of weight gain in this population. Further research is needed to design interventions that match survivors' needs.     

Resistance training volume, energy balance and weight management: rationale and design of a 9 month trial

The increased prevalence of obesity and the lack of treatment success both argue for the design and evaluation of strategies to prevent the development of overweight and obesity. To date, the role of resistance training (RT) in this regard is largely unexplored. RT may be effective for weight management as a result of increased fat-free mass (FFM), which may result in increased resting metabolic rate and increased physical activity energy expenditure. However, the literature relative to the efficacy of RT protocols recommended for healthy adults to alter the aforementioned parameters is inconsistent or inadequately evaluated. We will conduct a 9 month randomized controlled efficacy trial to compare changes in body composition (fat mass, FFM, % body fat) and energy balance in response to 2 volumes of RT (1 vs. 3 sets vs. non-exercise control) both at the completion of training (9 months) and 1 year later (body composition). This investigation will be conducted in a sample of healthy, normal and overweight, sedentary, young adult men and women; a group at high risk for development of overweight and obesity. Our results will provide information relative to the minimum volume of RT that may be associated with body weight/fat gain which may inform the development of guidelines for RT to prevent weight gain or to alter body composition.     

The effect of liraglutide, a long-acting glucagon-like peptide 1 derivative, on glycemic control, body composition, and 24-h energy expenditure in patients with type 2 diabetes

OBJECTIVE: Glucagon-like peptide (GLP)-1 is a gut hormone that exerts incretin effects and suppresses food intake in humans, but its therapeutic use is limited due to its short half-life. This was a randomized, double-blind, parallel-group, placebo-controlled trial investigating the effect of the long-acting GLP-1 derivative liraglutide (NN2211) on glycemic control, body weight, body composition, and 24-h energy expenditure in obese subjects with type 2 diabetes. RESEARCH DESIGN AND METHODS: Thirty-three patients (mean +/- SD) aged 60.0 +/- 9.5 years, with HbA(1c) 7.5 +/- 1.2% and BMI 36.6 +/- 4.1 kg/m(2), were randomized to treatment with a single daily subcutaneous dose of 0.6 mg liraglutide (n = 21) or placebo (n = 12) for 8 weeks. In addition to weight and glycemic parameters, body composition was assessed by dual-energy X-ray absorptiometry (DEXA) scanning and 24-h energy expenditure in a respiratory chamber. RESULTS: After 8 weeks, liraglutide reduced fasting serum glucose (liraglutide, -1.90 mmol/l, and placebo, 0.27 mmol/l; P = 0.002) and HbA(1c) (liraglutide, -0.33%, and placebo, 0.47%; P = 0.028) compared with placebo. No change in body weight was detected (liraglutide, -0.7 kg, and placebo, -0.9 kg; P = 0.756). There was a nonsignificant trend toward a decrease in total fat mass (liraglutide, -0.98%, and placebo, -0.12%; P = 0.088) and toward an increase in lean body mass (liraglutide, 1.02%, and placebo, 0.23%; P = 0.118) in the liraglutide group compared with the placebo group. Twenty-four-hour energy expenditure was unaffected by the treatment (liraglutide, -12.6 kJ/h, and placebo, -13.7 kJ/h; P = 0.799). CONCLUSIONS: Eight weeks of 0.6-mg liraglutide treatment significantly improved glycemic control without increasing weight in subjects with type 2 diabetes compared with those on placebo. No influence on 24-h energy expenditure was detected.     

Free-living energy expenditure reduced after deep brain stimulation surgery for Parkinson's disease

Background: The clinical picture in Parkinson’s disease (PD) is characterized by bradykinesia, rigidity, resting tremor and postural instability. In advanced stages of the disease, many patients will experience reduced efficacy of medication with fluctuations in symptoms and dyskinesias. Surgical treatment with deep brain stimulation in the subthalamic nucleus (STN‐DBS) is now considered the gold standard in fluctuating PD. Many patients experience a gain of weight following the surgery. The aim of this study was to identify possible mechanisms, which may contribute to body weight gain in patients with PD following bilateral STN‐DBS surgery. Methods: Ten patients with PD were studied before bilateral STN‐DBS surgery, and seven patients were studied again 3 and 12 months postoperatively. Clinical examination and resting metabolic rate with and without medical treatment was measured before and after STN‐DBS. Furthermore, free‐living energy expenditure, body composition, energy intake, peak oxygen consumption, maximal workload and leisure time physical activity were measured before and 3 and 12 months after surgery. Results: The STN‐DBS operated patients had a significant weight gain of 4·7 ± 1·6 kg (mean ± SE) 12 months postoperatively, and the weight gain was in the fat mass. The free‐living energy expenditure decreased postoperatively 13 ± 4% even though the reported dietary intake was reduced. A decreased energy expenditure took place in the non‐resting energy expenditure. The reported daily leisure time activity, peak oxygen consumption and maximal workload were unchanged. Conclusion: The STN‐DBS operated patients have a significant postoperative weight gain, as a result of a decrease in free‐living energy expenditure concomitant with an insufficient decrease in energy intake.     

Insulin resistance associated with lower rates of weight gain in Pima Indians.

Insulin resistance is commonly associated with obesity and noninsulin-dependent diabetes. Whereas it predicts the development of diabetes, its effect on body weight change is unknown. We measured glucose disposal rates at submaximally- and maximally-stimulating insulin concentrations in 192 nondiabetic Pima Indians and followed their weight change over 3.5 +/- 1.8 y (mean +/- SD). Results: (a) Insulin-resistant subjects gained less weight than insulin-sensitive subjects (3.1 vs. 7.6 kg, P less than 0.0001). (b) The percent weight change per year correlated with glucose disposal at submaximally-(r = 0.19, P less than 0.01) and maximally-stimulating (r = 0.34, P less than 0.0001) insulin concentrations independent of sex, age, initial weight, and 24-h energy expenditure; the correlations were stronger for glucose oxidation than for glucose storage. (c) Weight gain was associated with an increase in insulin resistance more than four times that predicted from the cross-sectional data. We conclude that insulin resistance is associated with a reduced risk of weight gain in nondiabetic Pima Indians.     

Is a failure to recognize an increase in food intake a key to understanding insulin-induced weight gain?

The present study aimed to assess the contribution of energy intake to positive energy balance and weight gain with insulin therapy. Changes in energy intake (self-report and weighed food intake), dietary behavior (auto-questionnaires), resting energy expenditure (REE) (indirect calorimetry), physical activity (accelerometry), and glucosuria were monitored over the first 6 months of insulin therapy in 46 diabetic adults. No change in REE, activity, or glucosuria could explain weight gain in the type 1 (4.1 +/- 0.6 kg, P < 0.0001) or type 2 (1.8 +/- 0.8 kg, P = 0.02) diabetic groups. An increase in energy intake provides the most likely explanation for weight gain with insulin. However, it is not being recognized because of significant underestimation of self-reported food intake, which appears to be associated with increased dietary restraint.     

Effects of postmenopausal hormone replacement therapy on central abdominal fat, glycemic control, lipid metabolism, and vascular factors in type 2 diabetes: a prospective study.

OBJECTIVE: To examine the effects of hormone replacement therapy (HRT) on lipid metabolism, glycemic control, total body and central abdominal fat, blood pressure (BP), and arterial pulse wave velocity (APWV) in overweight postmenopausal females with type 2 diabetes. RESEARCH DESIGN AND METHODS: This was a 12-month prospective study of 14 subjects (mean +/- SD age 57.5+/-5.6 years, BMI 29.5+/-4.8 kg/m2) randomized to 6 months of observation or HRT before crossover. HRT consisted of 2 months of conjugated equine estrogen (CEE) 0.625 mg daily, followed by 4 months CEE and medroxyprogesterone 5 mg daily. Measures included anthropometry, fasting glucose, insulin, HbA1c, total and HDL cholesterol, triglycerides, apolipoprotein B, LDL particle size, nonesterified fatty acids (NEFA), sex hormone-binding globulin, resting energy expenditure (REE), total and central abdominal fat (by dual-energy X-ray absorptiometry), resting BP, APWV (by applanation tonometry), physical activity, well-being, and sexual function. RESULTS: Six months of HRT resulted in significant reductions in waist-to-hip ratio (-0.03+/-0.01 vs. 0.01+/-0.009, P = 0.007), HbA1c (-0.34+/-0.24 vs. 0.6+/-0.4%, P = 0.04), total cholesterol (-0.6+/-0.1 vs. 0.2+/-0.2 mmol/l, P = 0.001), central abdominal fat (-175+/-51 vs. -24+/-56 g, P = 0.05), and improved physical functioning (P = 0.05), compared with observation. There was a minor increase in REE with HRT (33+/-23 vs. -38+/-23 kJ/day, P = 0.04). Total fat mass, fasting glucose, insulin, triglyceride, apolipoprotein B, NEFA, resting BP, APWV, and physical activity were unchanged. CONCLUSIONS: Postmenopausal HRT in these overweight women with type 2 diabetes was associated with a reduction in central adiposity and improvement in lipid metabolism and glycemic control without deterioration in weight status or cardiovascular parameters measured. Whether HRT-induced improvements in these cardiovascular risk factors result in lower long-term cardiovascular morbidity and mortality, as observed in nondiabetic women, awaits further study.     

Increased 24-h energy expenditure in type 2 diabetes

OBJECTIVE: The aim of this study was to determine whether overweight and obese individuals with type 2 diabetes have higher basal and 24-h energy expenditure compared with healthy control subjects before and after adjustment for body composition, spontaneous physical activity (SPA), sex, and age. RESEARCH DESIGN AND METHODS: Data from 31 subjects with type 2 diabetes and 61 nondiabetic control subjects were analyzed. The 24-h energy expenditure, basal metabolic rate (BMR), and sleeping energy expenditure (EEsleep) between 1:00 a.m. and 6:00 a.m. were measured in whole-body respiratory chambers. Body composition was assessed by dual-energy X-ray absorptiometry (DXA). RESULTS: No significant differences in unadjusted EEsleep, BMR, and 24-h energy expenditure were observed between the type 2 diabetic group and the control group. After adjustment for fat-free mass (FFM), fat mass, SPA, sex, and age, EEsleep and BMR were, respectively, 7.7 and 6.9% higher in the type 2 diabetic group compared with the control group. This was equivalent to 144 +/- 40 kcal/day (P = 0.001) and 139 +/- 61 kcal/day (P = 0.026), respectively. Adjusted 24-h energy expenditure was 6.5% higher in the type 2 diabetic group compared with the nondiabetic control subjects (2,679 +/- 37 vs. 2,515 +/- 23 kcal/day, P = 0.002). In multiple regression analyses, FFM, fat mass, SPA, and diabetes status were all significant determinants of EEsleep and 24-h energy expenditure, explaining 83 and 81% of the variation, respectively. CONCLUSIONS: This study confirms reports in Pima Indians that basal and 24-h energy expenditure adjusted for body composition, SPA, sex, and age are higher in individuals with type 2 diabetes compared with nondiabetic control subjects and may be even more pronounced in Caucasians.     

The impact of significant weight loss on resting energy expenditure in obese youth.

BACKGROUND: The prevalence of obesity in American youth is increasing and treating the condition is difficult. METHODS: We have developed a multidisciplinary weight-reduction program that includes a very low calorie diet followed by a hypocaloric diet, exercise, and behavior modification. Based on data collected at baseline and at the end of the acute intervention phase (10 weeks), we assessed the impact of the weight loss that resulted from participation in this weight reduction program on the resting energy expenditure and body composition of obese children and adolescents. RESULTS: There was a significant decrease in body weight and body fat as assessed by weight determinations and skin-fold measurements after 10 weeks. The body mass index decreased significantly from 33.8 on entry to 29.6 (P < 0.0001). Despite the significant weight loss, resting energy expenditure and lean body mass remained constant from entry until the completion of the acute phase. CONCLUSION: We conclude that a multidisciplinary weight-reduction program that combines a very low calorie diet followed by a balanced hypocaloric diet, with a moderate-intensity progressive exercise program and behavior modification is an effective means for weight-reduction in obese children and adolescents. Furthermore, fat mass is significantly reduced while lean body mass and resting energy expenditure are unaltered.     

Dietary-induced alterations in thyroid hormone metabolism during overnutrition.

Diet-induced alterations in thyroid hormone concentrations have been found in studies of long-term (7 mo) overfeeding in man (the Vermont Study). In these studies of weight gain in normal weight volunteers, increased calories were required to maintain weight after gain over and above that predicted from their increased size. This was associated with increased concentrations of triiodothyronine (T3). No change in the caloric requirement to maintain weight or concentrations of T3 was found after long-term (3 mo) fat overfeeding. In studies of short-term overfeeding (3 wk) the serum concentrations of T3 and its metabolic clearance were increased, resulting in a marked increase in the production rate of T3 irrespective of the composition of the diet overfed (carbohydrate 29.6 +/- 2.1 to 54.0 +/- 3.3, fat 28.2 +/- 3.7 to 49.1 +/- 3.4, and protein 31.2 +/- 2.1 to 53.2 +/- 3.7 microgram/d per 70 kg). Thyroxine production was unaltered by overfeeding (93.7 +/- 6.5 vs. 89.2 +/- 4.9 microgram/d per 70 kg). It is still speculative whether these dietary-induced alterations in thyroid hormone metabolism are responsible for the simultaneously increased expenditure of energy in these subjects and therefore might represent an important physiological adaptation in times of caloric affluence. During the weight-maintenance phases of the long-term overfeeding studies, concentrations of T3 were increased when carbohydrate was isocalorically substituted for fat in the diet. In short-term studies the peripheral concentrations of T3 and reverse T3 found during fasting were mimicked in direction, if not in degree, with equal or hypocaloric diets restricted in carbohydrate were fed. It is apparent from these studies that the caloric content as well as the composition of the diet, specifically, the carbohydrate content, can be important factors in regulating the peripheral metabolism of thyroid hormones.     

Energy expenditure and substrate metabolism measured by 24 h whole-body calorimetry in patients receiving cyclic and continuous total parenteral nutrition.

1. Twenty-four hour energy expenditure and its components, i.e. 'basal metabolic rate', activity energy expenditure and diet-induced thermogenesis were measured, using continuous whole-body indirect calorimetry, in patients receiving total parenteral nutrition while in remission from Crohn's disease (weight 51.9 +/- 9.9 kg, body mass index 19.2 +/- 2.0 kg/m2). 2. Total parenteral nutrition was infused continuously over 24 h in four subjects and cyclically, between 22.00 and 10.00 hours, in eight subjects. Twenty-four hour energy expenditure (6.83 +/- 1.10 MJ/24 h) was lower than total energy intake (10.09 +/- 1.63 MJ/24 h), resulting in a positive energy balance (3.26 +/- 1.42 MJ) in all subjects. Repeated measurements of resting energy expenditure in the continuously fed subjects (5.82 +/- 1.11 MJ/24 h) did not change significantly at different times of day (coefficient of variation 2.2-6.6%). In contrast, in cyclically fed subjects, resting energy expenditure was 24.2 +/- 9.0% higher towards the end of the 12 h feeding period than the 'basal metabolic rate', which was measured just before the start of the feeding period. 3. Diet-induced thermogenesis, calculated as the increment in resting energy expenditure above 'basal metabolic rate' over the 24 h period (adjusted for the reduction in energy expenditure during sleep), was found to be 0.60 +/- 0.29 MJ or 6.1 +/- 3.1% of the energy intake. 4. The energy cost of activity (activity energy expenditure) in the continuously fed patients, calculated as the difference between 24 h energy expenditure and the integrated 24 h measurements of resting energy expenditure, was 0.88 +/- 0.53 MJ, i.e. 12.9 +/- 5.9% of the 24 h energy expenditure. 5. The non-protein non-glycerol respiratory quotient exceeded 1.0 for varying periods of time (0.5-17 h) in 11 subjects, indicating net lipogenesis from carbohydrate. 6. The results demonstrate favourable rates of deposition, during intravenous feeding, of both energy and nitrogen over a 24 h period in patients recovering from an episode of Crohn's disease. The efficacy of these commonly used total parenteral nutrition regimens in these patients is related to three features that are absent in normal healthy individuals, namely a low basal metabolic rate, a low activity-related energy expenditure and prolonged periods of lipogenesis from carbohydrate.     

Thermic effect of food at rest, during exercise, and after exercise in lean and obese men of similar body weight.

The thermic effect of food at rest, during 30 min of cycle ergometer exercise, and after exercise was studied in eight lean (mean +/- SEM, 10 +/- 1% body fat, hydrostatically-determined) and eight obese men (30 +/- 2% body fat). The lean and obese mean were matched with respect to age, height, weight, and body mass index (BMI) to determine the relationship between thermogenesis and body composition, independent of body weight. All men were overweight, defined as a BMI between 26-34, but the obese had three times more body fat and significantly less lean body mass than the lean men. Metabolic rate was measured by indirect calorimetry under four conditions on separate mornings, in randomized order, after an overnight fast: 3 h of rest in the postabsorptive state; 3 h of rest after a 750-kcal mixed meal (14% protein, 31.5% fat, and 54.5% carbohydrate); during 30 min of cycling and for 3 h post exercise in the postabsorptive state; and during 30 min of cycling performed 30 min after the test meal and for 3 h post exercise. The thermic effect of food, which is the difference between postabsorptive and postprandial energy expenditure, was significantly higher for the lean than the obese men under the rest, post exercise, and exercise conditions: the increments in metabolic rate for the lean and obese men, respectively, were 48 +/- 7 vs. 28 +/- 4 kcal over 3 h rest (P less than 0.05); 44 +/- 7 vs. 16 +/- 5 kcal over 3 h post exercise (P less than 0.05); and 19 +/- 3 vs. 6 +/- 3 kcal over 30 min of exercise (P less than 0.05). The thermic effect of food was significantly negatively related to body fat content under the rest (r = -0.55), post exercise (r = -0.66), and exercise (r = -0.58) conditions. The results of this study indicate that for men of similar total body weight and BMI, body composition is a significant determinant of postprandial thermogenesis; the responses of obese are significantly blunted compared with those of lean men.     

High-intensity resistance training improves glycemic control in older patients with type 2 diabetes

OBJECTIVE: To examine the effect of high-intensity progressive resistance training combined with moderate weight loss on glycemic control and body composition in older patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Sedentary, overweight men and women with type 2 diabetes, aged 60-80 years (n = 36), were randomized to high-intensity progressive resistance training plus moderate weight loss (RT & WL group) or moderate weight loss plus a control program (WL group). Clinical and laboratory measurements were assessed at 0, 3, and 6 months. RESULTS: HbA(1c) fell significantly more in RT & WL than WL at 3 months (0.6 +/- 0.7 vs. 0.07 +/- 0.8%, P < 0.05) and 6 months (1.2 +/- 1.0 vs. 0.4 +/- 0.8%, P < 0.05). Similar reductions in body weight (RT & WL 2.5 +/- 2.9 vs. WL 3.1 +/- 2.1 kg) and fat mass (RT & WL 2.4 +/- 2.7 vs. WL 2.7 +/- 2.5 kg) were observed after 6 months. In contrast, lean body mass (LBM) increased in the RT & WL group (0.5 +/- 1.1 kg) and decreased in the WL group (0.4 +/- 1.0) after 6 months (P < 0.05). There were no between-group differences for fasting glucose, insulin, serum lipids and lipoproteins, or resting blood pressure. CONCLUSIONS: High-intensity progressive resistance training, in combination with moderate weight loss, was effective in improving glycemic control in older patients with type 2 diabetes. Additional benefits of improved muscular strength and LBM identify high-intensity resistance training as a feasible and effective component in the management program for older patients with type 2 diabetes.     

Short-term moderate weight loss and resistance training do not affect insulin-stimulated glucose disposal in postmenopausal women.

OBJECTIVES: Moderate weight loss and exercise have been proposed as important tools in the treatment and prevention of type 2 diabetes. Therefore, we tested the hypothesis that short-term (4 weeks) moderate energy restriction (-750 kcal/day) would result in a significant increase in insulin-stimulated glucose disposal (40 mU x m(-2) x min(-1) hyperinsulinemic-euglycemic clamp) in moderately overweight postmenopausal women and that when combined with resistance training (RT) an even greater effect would be seen. RESEARCH DESIGN AND METHODS: Older women were randomly assigned to energy restriction (WLoss group; n = 9) or energy restriction plus RT (RT + WLoss group; n = 10). RESULTS: For the WLoss versus the RT + WLoss groups, changes in body weight (-3.0 +/- 0.2 kg vs. -3.2 +/- 0.3 kg), fat mass (FM) (-3.0 +/- 0.3 kg vs. -3.2 +/- 0.3 kg), and percent body fat (BF) (-2.1 +/- 0.4 vs. -2.4 +/- 0.3%) were not different between groups. Muscle mass (group-by-time interaction, P = 0.04) was preserved in RT + WLoss (0.40 +/- 0.40 kg) and reduced in WLoss (-0.64 +/- 0.18 kg). There were no changes in fat-free mass (FFM) and waist-to-hip ratio in either group. Whole body glucose disposal (WLoss 6.14 +/- 0.57 vs. 6.03 +/- 0.53, RT + WLoss 5.85 +/- 0.60 vs. 6.09 +/- 0.56 mg/kg of FFM/min) did not change in either group. CONCLUSIONS: The results of this study demonstrate that short-term energy restriction resulting in moderate decreases in body weight (4.0 +/- 0.3%) and FM (8.2 +/- 0.7%) did not improve insulin-stimulated glucose disposal. The addition of RT to the hypoenergetic diet preserved muscle mass but provided no synergistic effect on insulin action. These results suggest that a greater change in body weight or FM may be necessary to observe a significant improvement in insulin action.     

Effects of energy-restricted diets containing increased protein on weight loss, resting energy expenditure, and the thermic effect of feeding in type 2 diabetes

OBJECTIVE: To determine the effect of a high-protein (HP) diet compared with a low-protein (LP) diet on weight loss, resting energy expenditure (REE), and the thermic effect of food (TEF) in subjects with type 2 diabetes during moderate energy restriction. RESEARCH DESIGN AND METHODS: In this study, 26 obese subjects with type 2 diabetes consumed a HP (28% protein, 42% carbohydrate) or LP diet (16% protein, 55% carbohydrate) during 8 weeks of energy restriction (1,600 kcal/day) and 4 weeks of energy balance. Body weight and composition and REE were measured, and the TEF in response to a HP or LP meal was determined for 2 h, at weeks 0 and 12. RESULTS: The mean weight loss was 4.6 +/- 0.4 kg (P < 0.001), of which 4.5 +/- 0.4 kg was fat (P < 0.001), with no effect of diet (P = 0.6). At both weeks 0 and 12, TEF was greater after the HP than after the LP meal (0.064 vs. 0.050 kcal x kcal(-1) energy consumed x 2 h(-1), respectively; overall diet effect, P = 0.003). REE and TEF were reduced similarly with each of the diets (time effects, P = 0.02 and P < 0.001, respectively). CONCLUSIONS: In patients with type 2 diabetes, a low-fat diet with an increased protein-to-carbohydrate ratio does not significantly increase weight loss or blunt the fall in REE.     

Energy expenditure in non-insulin dependent diabetic subjects on metformin or sulphonylurea therapy

In the management of the non-insulin dependent diabetic patient, metformin often facilitates weight loss whereas sulphonylurea may predispose to weight gain. To investigate whether this is due to alterations in energy expenditure we have studied energy expenditure in seven non-insulin dependent diabetic subjects while on metformin or sulphonylurea therapy. Three components of energy expenditure were measured by indirect calorimetry, namely resting metabolic rate and the thermic responses to infused noradrenaline and to a mixed constituent meal. There was no significant difference in the resting metabolic rate on metformin (5.29 +/- 0.41 kJ/min; mean +/- SE) compared with sulphonylurea (5.34 +/- 0.34 kJ/min). The resting metabolic rate was also similar to predicted values for non-diabetic subjects (r = 0.96). The thermic response to infused noradrenaline was similar on metformin (23.14 +/- 1.87 kJ) and sulphonylurea (21.40 +/- 2.98 kJ). There was no significant difference in the thermic response to the meal on sulphonylurea (75.8 +/- 7.5 kJ) or on metformin (86.8 +/- 10.8 kJ; 95% confidence limits -17 to +39 kJ). We conclude that in non-insulin dependent diabetic subjects metformin does not enhance energy expenditure overall, compared with sulphonylurea.     

Graphical exploration of dimensions of preterm infant growth in weight in association with biological, nutritional, and energy expenditure conditions

The small sample sizes of studies involving preterm infants limit the use of statistics for examination of multivariate conditions contributing to clinically important growth dimensions of weight: rate of weight gain, body composition (fat-free and fat mass), and weight relative to reference infants (z score). The authors used graphical analyses, including multivariate proportional matrix, parallel coordinates, and bivariate plots with regression lines and splines, to explore specific variables derived from a theoretical model of biological, nutritional intake, and energy expenditure conditions influencing growth dimensions. The sample included 28 infants in 4 birth-weight categories: extremely low (<1,000 g), very low/smaller (1,000-1,249 g), very low/larger (1,250-1,499 g), and low (1,500-1,750 g). The authors examined the rate of weight gain before and after nipple feeding initiation. Fat-free mass was estimated with total body water and fetal reference data, and fat mass with skinfold thicknesses. Despite infants achieving the expected rate of weight gain for a fetus of the same postconceptional age, by hospital discharge 13 infants showed growth restriction with weight <10th centile. Infants with respiratory distress syndrome history were highest in negative z-score change from regain of birth weight to discharge, despite higher ordering on protein intake and fat-free mass. Graphical analyses provided visual patterns of distributions and orderings of measures of multiple variables that, taken together, identified potential influencing conditions and raised questions for further study. Other variables, including feeding protocols and practices, infant feeding competence, and health status, may contribute to variability in weight growth dimensions and influence relationships with biologic, nutritional, and energy expenditure conditions.