Maintenance Of Lean Body Mass Research Articles

Breakfast Protein Intake of One-third of Daily Requirement Can Maintain Lean Body Mass Post-distal Gastrectomy.

Post-gastrectomy lean body mass (LBM) decrease has a significant negative impact on postoperative survival in patients with cancer. This study investigated the effect of intake of at least one-third of the daily protein requirement at breakfast on the maintenance of LBM in patients during the first month post-gastrectomy. Among patients with gastric cancer who underwent curative distal gastrectomy between April 2011 and December 2018, without adjuvant chemotherapy, we evaluated 401 patients who had consumed more than the daily protein requirement in the first month postoperatively, using the FFQW82 nutrition intake questionnaire. Patients were divided into those who consumed more (≥1/3 intake group, n=160) and those who consumed less than one-third of the daily protein requirement at breakfast (<1/3 intake group, n=241). We compared the LBM reduction rate at one month postoperatively between groups. Univariate and multivariate analyses were performed to determine clinicopathological factors predicting LBM reduction at one month postoperatively. The LBM reduction rate at one month post-curative distal gastrectomy was significantly higher in the <1/3 intake group than in the ≥1.3 intake group (p=0.01) at breakfast. Multivariate analysis showed that morning protein intake below one-third of the daily requirement independently predicted LBM reduction (odds ratio=1.75, 95% confidence interval=1.14-2.68, p<0.01). Consuming at least one-third of the daily protein requirement at breakfast may be effective in maintaining LBM in patients undergoing curative distal gastrectomy. These results may be very important for prognosis, since maintaining LBM influences the continuation of adjuvant chemotherapy and thus survival after curative resection in patients with gastric cancer.

Approaching the Sarcopenic Patient with Nonalcoholic Steatohepatitis-related Cirrhosis.

Sarcopenia is a well-known complication of chronic liver disease (CLD), and it is almost always observed in patients with cirrhosis, at least in those with decompensated disease. Since nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is becoming the leading cause of end-stage liver disease, a new scenario characterized by the frequent coexistence of NAFLD, obesity, and sarcopenia is emerging. Although it is not yet resolved whether the bidirectional relationship between sarcopenia and NAFLD subtends causal determinants, it is clear that the interaction of these two conditions is associated with an increased risk of poor outcomes. Notably, during the course of CLD, deregulation of the liver-muscle-adipose tissue axis has been described. Unfortunately, owing to the lack of properly designed studies, specific therapeutic guidelines for patients with sarcopenia in the context of NAFLD-related CLD have not yet been defined. Strategies aimed to induce the loss of fat mass together with the maintenance of lean body mass seem most appropriate. This can be achieved by properly designed diets integrated with specific nutritional supplementations and accompanied by adequate physical exercise. Future studies aiming to add to the knowledge of the correct assessment and approach to sarcopenia in the context of NAFLD-related CLD are eagerly awaited.

61 Life Stage Feeding: Is There Path Forward for Senior/Geriatric Nutrient recommendations?

Abstract Complete and balanced foods for “all life stages”, according to the Association of American Feed Control Officials (AAFCO), meet the needs for reproduction and growth. While these are recognized as the most nutritionally demanding stages, they are relatively short time periods in the life of a pet. Unique to companion animals, and humans, is the prolonged “senior” life stage. Although this stage is not well defined, it has become evident that energy, protein and other nutrient requirements may change with age in seniors. To establish guidelines for a lifestage, that lifestage must be defined (Table 1). Species and breed differences exist in terms of aging, in that small breed dogs have longer lifespans versus large breed dogs, and cats differ from dogs, with cats showing a definable fourth lifestage of “geriatric” that differs from a “senior” lifestage. A major challenge to defining senior or geriatric nutritional needs is the fact that animals “age” at different rates, causing senior/geriatric to be the most physiologically diverse lifestage. In nutritionally complete and balanced foods, nutrients are provided in proportion to the energy content of the diet and to the expected energy intake of the pet. Regardless of lifestage, energy requirements can differ significantly among dog breeds and among individuals. Added to this is evidence that energy requirements in dogs decrease with age, such that senior dogs need about 25% fewer calories, on average, than young adult dogs. Likewise, senior cats show a decrease in energy requirements, but geriatric cats display an increase in energy needs. Thus, even if the absolute requirement for nutrients did not change with age, the content needed on an energy basis will change. One of the challenges to establishing protein requirements for senior and geriatric pets is age-related loss of lean body mass (LBM), or sarcopenia. LBM serves as a protein reservoir and provides the amino acids used on a 24/7 basis for endogenous protein synthesis, while dietary protein maintains or restores this reservoir. It has become evident that nitrogen balance studies, long used to determine protein requirements for adults, are not sufficient in that they do not account for contributions from LBM. Maintenance of LBM may be a better assay for defining protein requirements. However, LBM is lost with age in all species studied, including humans, dogs and cats. Geriatric cats lose approximately one third of their LBM, while senior dogs lose about 10%. Loss of LBM is associated with greater morbidity and mortality, thus, preservation of LBM is an important goal. While increasing protein intake can slow the loss, and vice versa, increasing protein intake alone cannot prevent loss of LBM. Therefore, an important challenge is to determine how to measure protein requirements in aging pets.

Body Composition and Metabolic Improvement in Patients Followed Up by a Multidisciplinary Team for Obesity in China.

Background This study evaluated the effectiveness of the multidisciplinary team (including a specialist, a dietitian, a physical exercise trainer, a surgeon for bariatric surgery, an acupuncturist, and several health educators) for obesity management and the body composition change and improvements in metabolic biomarkers during a 2-year follow-up. Materials and Methods A total of 119 patients participated in the multidisciplinary team for obesity. Patients were followed up at 3 months, 6 months, 1 year, 18 months, and 2 years after their first visit. Individuals were divided into the high-protein diet (HPD) and standard-protein diet (SPD) group according to their results on a diet questionnaire that they filled out during follow-up. Results After 1.2 years, the mean body weight of the participants dropped from 89.7 kg to 80.9 kg (p < 0.001). The body adiposity index was reduced from 33.9 to 32.0 (p < 0.001), while the fat-free mass index from 17.0 to 15.2 (p = 0.043). Fasting glucose and HbA1c were also lower after treatment (p = 0.002 and 0.038 for FPG and HbA1c, respectively). Fasting insulin and HOMA-IR were reduced (p = 0.002 and <0.001 for fasting insulin and HOMA-IR, respectively). HDL-c increased along with weight loss (1.06 mmol/L vs. 1.19 mmol/L, p < 0.001), and transaminase levels significantly dropped (p = 0.001 and 0.021 for ALT and AST, respectively). During treatment, mean protein intake was 29.9% in the HPD group and 19.5% in the SPD group (p < 0.001). Weight loss, reduction of visceral fat area, maintenance of lean body mass, body adiposity index, and fat-free mass index showed no statistical significance between the HPD and SPD groups, as well as glucose metabolic variables. Conclusions A multidisciplinary team for obesity management could significantly reduce body weight and improve metabolic indicators, including HDL-c, transaminase, and insulin resistance. A high-protein diet does not produce better weight control or body composition compared with a standard calorie-restricted diet.

Metabolic Consequences of Supplemented Methionine in a Clinical Context

The central position of methionine (Met) in protein metabolism indicates the importance of this essential amino acid for growth and maintenance of lean body mass. Therefore, Met might be a tempting candidate for supplementation. However, because Met is also the precursor of homocysteine (Hcy), a deficient intake of B vitamins or excessive intake of Met may result in hyperhomocysteinemia (HHcy), which is a risk factor for cardiovascular disease. This review discusses the evidence generated in preclinical and clinical studies on the importance and potentially harmful effects of Met supplementation and elaborates on potential clinical applications of supplemental Met with reference to clinical studies performed over the past 20 y. Recently acquired knowledge about the NOAEL (no observed adverse effect level) of 46.3mg · kg-1 · d-1 and the LOAEL (lowest observed adverse effect level) of 91mg · kg-1 · d-1 of supplemented Met will guide the design of future studies to further establish the role of Met as a potential (safe) candidate for nutritional supplementation in clinical applications.

Impacto do exercício físico em idosos com baixo peso: uma abordagem focada na sarcopenia

OBJECTIVE: Verify the impact of physical exercise practice in elders with low weight and sarcopenia, since the latter is a component often associated with thinness in the elderly population. In the same way, it seeks to elicit the effects of a sedentary lifestyle on these same variables. METHODOLOGICAL DELINEATION: Integrative review of PubMed, Scielo and Lilacs databases between 2014 and 2019 using Descritores em Ciência e Saúde (DeCS) (sarcopenia, idoso, perda de peso, exercício and estilo de vida sedentário) and Medical Subject Headings (MeSH) (aged, aged 80 and over, weight loss, sarcopenia, thinness, exercise and sedentary behavior). RESULTS: Fourteen articles were included in the synthesis. A sedentary lifestyle can lead to loss of strength and muscle mass among the elderly. Older people who practice physical activity have improved performance and muscle mass, functional capacity, and strength. CONCLUSION: In general, the articles demonstrated that physical activity assists in the maintenance of lean body mass and the potentiation of protein anabolism in the elderly and sarcopenic population, besides being a preventive factor.

Addressing the Double Burden of Malnutrition in Developing Countries: Need for Strategies to Improve the Lean Body Mass.

The double burden of childhood undernutrition and adult-onset adiposity-related chronic diseases is a key concern in many developing countries that are currently undergoing epidemiological and nutrition transition. Impaired linear growth with suboptimal lean body mass development seems to be the link between these 2 seemingly contrasting forms of malnutrition. Studies assessing the role of early nutrition in the later lean body mass development have shown consistent positive association. In addition, the nutrition during life course, especially the dietary intake of protein, zinc, calcium, and vitamin D status, impacts the lean body mass. Promoting increased intake of these important nutrients throughout life course would, therefore, be important for optimal development and maintenance of lean body mass. Diversified diets with increased consumption of nutrient-rich foods, especially milk and other animal source foods, are crucial for the development of optimal body composition and alleviation of the double burden of malnutrition.

Evidence of longer life; a cohort of 39 labrador retrievers

A panel of veterinary and academic experts reviewed current available evidence on age at death for labradors and reached a consensus that their average/typical life span was 12 years of...

BMI and healthy life expectancy in old and very old women

There is conflicting evidence for the effect of BMI on mortality at older ages, and little information on its effect on healthy life expectancy (HLE). Longitudinal data were from the 1921-1926 cohort of the Australian Longitudinal Study on Women's Health (n 11 119), over 18 years of follow-up. Self-rated health status was measured at each survey, and BMI was measured at baseline. Multi-state models were fitted to estimate the effect of BMI on total life expectancy (TLE) and HLE. Compared with women of normal weight, overweight women at the age of 75 years had similar TLE but fewer years healthy (-0·79; 95 % CI -1·21, -0·37) and more years unhealthy (0·99; 95 % CI 0·56, 1·42). Obese women at the age of 75 years lived fewer years in total than normal-weight women (-1·09; 95 % CI -1·77, -0·41), and had more unhealthy years (1·46; 95 % CI 0·97, 1·95 years). Underweight women had the lowest TLE and the fewest years of healthy life. Women should aim to enter old age at a normal weight and in good health, as the slight benefit on mortality of being overweight is offset by spending fewer years healthy. All outcomes were better for those who began in good health. The relationship between weight and HLE has important implications for nutrition for older people, particularly maintenance of lean body mass and prevention of obesity. The benefit of weight loss in obese older women remains unclear, but we support the recommendation that weight-loss advice be individualised, as any benefits may not outweigh the risks in healthy obese older adults.

Exceptional longevity and potential determinants of successful ageing in a cohort of 39 Labrador retrievers: results of a prospective longitudinal study.

BackgroundThe aim of this study was to describe the longevity and causes of mortality in 39 (12 males, 27 females) pedigree adult neutered Labrador retrievers with a median age of 6.5 years at the start of the study and kept under similar housing and management conditions. Body condition score was maintained between two and four on a 5-point scale by varying food allowances quarterly. The impact of change in body weight (BW) and body composition on longevity was analysed using linear mixed models with random slopes and intercepts.ResultsOn 31 July 2014, 10 years after study start, dogs were classified into three lifespan groups: 13 (33 %) Expected (≥9 to ≤12.9 years), 15 (39 %) Long (≥13 to ≤15.5 years) and 11 (28 %) Exceptional (≥15.6 years) with five still alive. Gender and age at neutering were not associated with longevity (P ≥ 0.06). BW increased similarly for all lifespan groups up to age 9, thereafter, from 9 to 13 years, Exceptional dogs gained and Long-lifespan dogs lost weight (P = 0.007). Dual-energy x-ray absorptiometer scans revealed that absolute fat mass increase was slower to age 13 for Long compared with Expected lifespan dogs (P = 0.003) whilst all groups lost a similar amount of absolute lean mass (P > 0.05). Percent fat increase and percent lean loss were slower, whilst the change in fat:lean was smaller, in both the Exceptional and Long lifespan compared with Expected dogs to age 13 (P ≤ 0.02). Total bone mineral density was significantly lower for Expected compared to Exceptional and Long lifespan dogs (P < 0.04).ConclusionsThis study shows that life-long maintenance of lean body mass and attenuated accumulation of body fat were key factors in achieving a longer lifespan. The results suggest that a combination of a high quality plane of nutrition with appropriate husbandry and healthcare are important in obtaining a greater than expected proportion of Labrador retrievers living well beyond that of the expected breed lifespan: 89.7 % (95 % CI 74.8–96.7 %) dogs were alive at 12 years of age and 28.2 % (95 % CI 15.6–45.1 %) reaching an exceptional lifespan of ≥15.6 years.

ID: 47: Nutritional L-leucine supplementation modulates muscle protein wasting and pro-inflammatory cytokines in Walker-256 tumour-bearing rats

Cancer cachexia is characterised by involuntary weight loss; the maintenance of lean body mass in cachectic hosts may contribute to a reduction in the number of deaths and an overall improvement in quality of life. The branched chain amino acid leucine affects cell signalling, thereby leading to an improvement in lean body mass by decreasing muscle protein degradation. We assess the effects of a leucine-rich diet on protein degradation signalling in muscle over the course of tumour growth. Adult Wistar rats were distributed into experimental groups according to whether a tumour or not was inoculated and whether or not a leucine-rich diet was provided. The animals were subsequently sacrificed at three different time points during tumour evolution (7th, 14th and 21st day after tumour implant). Protein degradation signalling, as indicated by ubiquitin–proteasome subunits (11S, 19S and 20S), and pro- and anti-inflammatory cytokines were analysed in each of the experimental groups. Tumour growth promoted a decrease in muscle protein, a sharp increase in pro-inflammatory cytokines (TNF α , IL-6 and IFN γ ) and a progressive increase in proteasome subunits (19S and 20S). Thus, the role of leucine in this specific situation reveals an increased process mainly on the 14th day after tumour implantation and a modulated action on the 21st day of tumour growth. The results indicate that leucine in the diet modulates some important key aspects of the proteasome pathway and inflammatory process in the cancer cachexia state.

Resistance exercise is medicine: Strength training in health promotion and rehabilitation

The benefits of aerobic training in health promotion are well documented, and this mode of exercise training continues to be the gold standard for health professionals when prescribing exercise programmes. However, resistance training has a wealth of unique benefits over those of aerobic training. It is these unique benefits that demonstrate the necessary role of resistance training in health promotion. The aim of this article is to demonstrate that resistance training is equally, and in some cases superior, to aerobic training in its health-promoting benefits, such as the increasing and/or maintenance of lean body mass and bone mineral density. As such, resistance training should be considered an integral component, along with aerobic and flexibility training, in any exercise programme designed to promote health in all populations. However, it is essential for health professionals to understand and differentiate the subtypes of resistance training as these will have different impacts on sports performance, health promotion and rehabilitation.

Scientific Opinion on the substantiation of a health claim related to fat-free yogurts and fermented milks with live yogurt cultures complying with the specifications “fat free”, “low in sugars”, “high protein”, “source of calcium” and “source of vitamin

Following an application from Federacion Nacional de Industrias Lacteas (FeNIL), submitted pursuant to Article 13.5 of Regulation (EC) No 1924/2006 via the Competent Authority of Spain, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to fat-free yogurts and fermented milks with live yogurt cultures complying with the specifications “fat free”, “low in sugars”, “high protein”, “source of calcium” and “source of vitamin D” for nutrition claims and maintenance of lean body mass in the context of an energy-restricted diet. The Panel considers that the food that is the subject of the claim, fat-free yogurts and fermented milks complying with the specifications “fat free”, “low in sugars”, “high protein”, “source of calcium” and “source of vitamin D” for nutrition claims, is sufficiently characterised. The Panel considers that maintenance of lean body mass in the context of an energy-restricted diet is a beneficial physiological effect. No human intervention studies from which conclusions could be drawn for the scientific substantiation of the claim were provided. The Panel concludes that a cause and effect relationship has not been established between the consumption of fat-free yogurts and fermented milks with live yogurt cultures complying with the specifications “fat free”, “low in sugars”, “high protein”, “source of calcium” and “source of vitamin D” for nutrition claims and maintenance of lean body mass in the context of an energy-restricted diet.

Dietary Protein and the Blood Glucose Concentration

Body proteins are being synthesized and degraded continuously (1). The estimated turnover is ∼210 g/day (2). Amino acids resulting from protein degradation can be recycled (reused for synthesis), but this is incomplete. Therefore, dietary protein is necessary for maintenance of lean body mass. Also, dietary protein is required to replace protein lost from the shedding of skin, hair, nails, cells in the gastrointestinal tract, and protein-containing secretions. However, the actual losses are estimated to be only 6–8 g/day (3). Overall, approximately ∼32–46 g of high-quality dietary protein/day is reported to be required to maintain protein balance (2). This is considerably less than amounts of protein reportedly consumed by American adults (∼65–100+ g/day) (4). The excess food-derived amino acids then are oxidized as fuel directly or indirectly after conversion to glucose. In 1915, using a phlorhizinized dog preparation, Janney (5) demonstrated clearly that the deaminated amino acids (carbon skeletons) present in dietary proteins could be used to produce glucose endogenously. For most common proteins, 50–80 g of glucose can be derived from 100 g of ingested protein. Nevertheless, as early as 1913, Jacobson (6) reported that ingestion of proteins did not raise the blood glucose. Later, in 1924, MacLean (7) fed 50 g of meat protein to two subjects, one with and one without mild diabetes. The …

Glomerular filtration rate after a 12-wk resistance exercise program with post-exercise protein ingestion in community dwelling elderly

ObjectiveIncreased protein intake and resistance exercise can be beneficial for maintenance of lean body mass (LBM) in older adults. However, these factors could also negatively affect renal function. We investigated changes in renal function after a 12-wk resistance exercise program combined with protein supplementation in community dwelling older adults. MethodsPatients (N = 237, 73.7 ± 5.7 y, 58.2% female) participated in a 12-wk resistance exercise program (3 times/wk) designed to increase strength and muscle mass of major muscle groups. Participants were randomly assigned to one of three dietary supplements consumed directly after training: whey protein drink (20 g whey protein, 20 g carbohydrates), milk protein drink (20 g milk protein, 20 g carbohydrates), or carbohydrate drink (40 g carbohydrates). Renal function was estimated as glomerular filtration rate (GFR, Cockcroft-Gault formula), and dietary intake was measured as 3-d-weighed food record at baseline and endpoint. ResultsDuring the intervention, energy intake did not increase. Carbohydrate intake increased in the carbohydrate group and protein intake increased in the milk group, both approximately in accordance with the supplementation. In the whey group, protein intake did not increase, but carbohydrate intake did. GFR increased after the intervention (+4.4 mL/min/1.73 m2; P < 0.001), and the changes were similar in men and women or in the age quartiles. Changes in GFR at endpoint were not associated with LBM, dietary supplements, or total protein intake. ConclusionsA 12-wk resistance exercise program combined with protein supplementation in community dwelling older adults does not negatively affect GFR. The supplementation had only minor effects on total dietary intake.

The Effects of Green Tea Consumption and Resistance Training on Body Composition and Resting Metabolic Rate in Overweight or Obese Women

Green tea has been shown to have thermogenic and antiobesity properties. Therefore, it is important to investigate its effect on weight loss in humans, especially in women. We investigated the effects of green tea consumption combined with resistance training on the body composition and the resting metabolic rate (RMR) in women who were overweight or obese (grade I). After 4 weeks on an adaptive diet, 36 women were divided into four groups (group 1 green tea; group 2 placebo; group 3 green tea plus resistance training; group 4 placebo plus resistance training). The study was double-blinded and placebo-controlled. The RMR and body composition were ascertained for each volunteer, blood tests were performed, and subjects in groups 3 and 4 were tested for their one repetition maximum. Each subject followed the protocol and continued the diet for eight additional weeks, and periodic evaluations were administered. The mean RMR of group 1 decreased significantly and was accompanied by weight loss, maintenance of lean body mass, and decreases in both waist circumference and body mass index. Group 2 showed no variations in anthropometric or blood variables and significantly decreased their mean RMR. Group 3 showed significant increases in RMR, lean body mass, and muscle strength, and significant decreases in body fat, triglycerides, and waist circumference as compared to group 4. Green tea combined with resistance training its potential is increased with decreasing body fat, waist circumference, and triacylglyceride levels and by increasing lean body mass and muscle strength.

How dieting makes some fatter: from a perspective of human body composition autoregulation

Dieting makes you fat - the title of a book published in 1983 - embodies the notion that dieting to control body weight predisposes the individual to acquire even more body fat. While this notion is controversial, its debate underscores the large gap that exists in our understanding of basic physiological laws that govern the regulation of human body composition. A striking example is the key role attributed to adipokines as feedback signals between adipose tissue depletion and compensatory increases in food intake. Yet, the relative importance of fat depletion per se as a determinant of post-dieting hyperphagia is unknown. On the other hand, the question of whether the depletion of lean tissues can provide feedback signals on the hunger-appetite drive is rarely invoked, despite evidence that food intake during growth is dominated by the impetus for lean tissue deposition, amidst proposals for the existence of protein-static mechanisms for the regulation of growth and maintenance of lean body mass. In fact, a feedback loop between fat depletion and food intake cannot explain why human subjects recovering from starvation continue to overeat well after body fat has been restored to pre-starvation values, thereby contributing to 'fat overshooting'. In addressing the plausibility and mechanistic basis by which dieting may predispose to increased fatness, this paper integrates the results derived from re-analysis of classic longitudinal studies of human starvation and refeeding. These suggest that feedback signals from both fat and lean tissues contribute to recovering body weight through effects on energy intake and thermogenesis, and that a faster rate of fat recovery relative to lean tissue recovery is a central outcome of body composition autoregulation that drives fat overshooting. A main implication of these findings is that the risk of becoming fatter in response to dieting is greater in lean than in obese individuals.

816 Changes in Body Composition after Lung Transplant in Children

Maintenance of lean body mass (LBM) influences survival and respiratory function and regulates growth in children. Changes in weight and body composition in pediatric patients after lung transplantation (LTR) have not been investigated. We retrospectively evaluated the changes in weight, lean body mass (LBM) and body fat (BF) prior to and up to 2 years post-LTR.

Overeating and Overweight

OVERWEIGHT AND OBESITY AFFECT 65% OF THE US public and the US government spends in excess of $200 billion per year on obesityassociated conditions and diseases. For the first time in human history, there are more overweight people (2.1 billion) in the world than underweight individuals. Forecasts suggest that the prevalence of obesity will double worldwide in the next 30 years, with the epicenter of the epidemic in China and India as persons in these countries assume Western eating habits. In this issue of JAMA, Bray and colleagues in a randomized controlled trial evaluated the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition. They found that body fat increased in proportion to excess calories but overall weight gain was less with low protein relative to normal or high protein diets. These findings have important ramifications because the Western diet tends to be high in fat and carbohydrates and low in protein. The study results also suggest that body weight may underestimate the true hazards of overnutrition. Obesity results from accumulation of excess body fat. Obesity is not simply excess body weight because overweight can occur from either muscle or fat deposition. Body weight and body mass index are useful in population studies in which excess weight represents excess body fat. However, on an individual level, sex, ethnicity, age, and as Bray et al showed, diet composition can affect the relationship between total body fat and body weight. Accumulation of excess fat is associated with obesity-related medical conditions, whereas increased muscle mass is beneficial because of its positive effect on metabolism. Excess abdominal fat and ectopic fat in the liver, pancreas, and heart can affect inflammation and increase the risk of a number of common obesity-associated disorders. Humans are better adapted to starvation with subsequent maintenance of lean body mass than they are to overfeeding, which results in body fat accumulation. Animal studies and some human studies have suggested a teleological adaptation to ingestion of foods having incorrect amounts of nutrients by burning off excess calories with dietinduced thermogenesis. In animals, brown fat creates heat and the animal is capable of burning off excess calories. Animals can eat foods with incorrect amounts of nutrients and not become fat because of this physiological adaptation. Adult humans have little brown fat. Nevertheless, it has been hypothesized that similar mechanisms could occur in humans, which led Bray et al to perform their study. Bray et al confined healthy human volunteers to an in-house environment in which they were deliberately overfed approximately 1000 calories daily (40% more energy than required for weight maintenance) with diets of varying protein content for 8 weeks. Overeating produced significantly less weight gain in the low protein group (approximately 3 kg) compared with the normal or high protein groups (approximately 6 kg). Total body fat measured by dual-energy x-ray absorptiometry increased similarly in all 3 groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure and body protein increased significantly only with the normal and high protein diets but not with the low protein diet. This study demonstrates how low protein foods with hidden sugars or fats may be contributing to the obesity epidemic. Sugars such as sucrose, fructose, and high fructose corn syrup are converted efficiently to fat with calorie excess. Carbohydrates and protein elicit different signaling pathways for muscle and fat cells. Therefore, when individuals consume excess carbohydrates out of proportion to protein, the body may gain less weight than when protein is consumed in adequate amounts. The study by Bray et al demonstrated that the lesser added weight consists largely of fat mass rather than lean body mass when excess calories were the same. Moreover, added fat calories (including hidden fat in processed foods) consumed in excess will also lead to weight gain contributing to the obesity epidemic. A large and well-accepted body of scientific evidence indicates that protein is the most satiating of the macronutrients. High protein diets providing 25% of total energy com-

Effects of Tai Chi Chuan on Insulin and Cytokine Levels in a Randomized Controlled Pilot Study on Breast Cancer Survivors

Background Tai Chi Chuan (TCC) is an integrative medicine mind-body practice with a physical activity component that has positive effects on aerobic capacity, muscular strength, and quality of life among cancer survivors, similar to the effects elicited by other modes of moderate-intensity exercise. Inflammatory cytokines and insulin and insulin-related signaling molecules may contribute to weight gain and affect cancer recurrence rates and survival; exercise can curb cancer- and treatment-related weight gain, increase survival, and reduce levels of insulin and inflammatory cytokines. Despite knowing the beneficial effects of conventional exercise interventions on these mediators, little is known about the physiologic effects of TCC on these pathways in breast cancer survivors. Methods We assessed the effects of a 12-week, moderately intense, TCC intervention (n = 9) compared with a non–physical activity control (n = 10) consisting of psychosocial support therapy (PST), on levels of insulin, insulin-like growth factor (IGF)-1, insulin growth factor-like binding protein (IGFBP)-1, IGFBP-3, and cytokines interleukin (IL)-6, IL-2, and interferon (IFN)-γ in breast cancer survivors. Results Levels of insulin are significantly different in TCC and PST groups; levels remained stable in the TCC group but increased in the PST control group ( P = .099). Bivariate analysis revealed novel and significant correlations (all r > 0.45, all P ≤ .05) of both decreased fat mass and increased fat-free mass with increased IL-6 and decreased IL-2 levels. Conclusions This pilot study shows that TCC may be associated with maintenance of insulin levels and changes in cytokine levels that may be important for maintenance of lean body mass in breast cancer survivors.