Physical activity, energy balance and obesity

Obesity appears when energy intake exceeds energy expenditure. The most important variable compound of energy expenditure is physical activity. The global epidemics of obesity seem closely related to reduced physical activity and sedentariness widely increasing nowadays. Once obesity has developed, caloric intake becomes similar to energy expenditure. To lose weight, besides decreasing energy intake, energy expenditure must be increased. The promotion of physical activity is difficult and so the results of treatment of obesity are discouraging for doctors, other health professionals and patients. Proactive efforts from patients and health providers with an intensive feedback between them may be extremely helpful. Nevertheless, more studies are needed to provide better approaches on the role of physical activity for the prevention and treatment of obesity and for long-term weight-loss maintenance.

Balance positivo en la atención al tabaquismo en Andalucía durante 2007

Boletín semanal para profesionales sanitarios de la Secretaría General de Salud Pública y Participación Social de la Consejería de Salud

Protocol for the modeling the epidemiologic transition study: a longitudinal observational study of energy balance and change in body weight, diabetes and cardiovascular disease risk.

ABSTRACT: BACKGROUND: The prevalence of obesity has increased in societies of all socio-cultural backgrounds. To date, guidelines set forward to prevent obesity have universally emphasized optimal levels of physical activity. However there are few empirical data to support the assertion that low levels of energy expenditure in activity is a causal factor in the current obesity epidemic are very limited. METHODS: The Modeling the Epidemiologic Transition Study (METS) is a cohort study designed to assess the association between physical activity levels and relative weight, weight gain and diabetes and cardiovascular disease risk in five population-based samples at different stages of economic development. Twenty-five hundred young adults, ages 25-45, were enrolled in the study; 500 from sites in Ghana, South Africa, Seychelles, Jamaica and the United States. At baseline, physical activity levels were assessed using accelerometry and a questionnaire in all participants and by doubly labeled water in a subsample of 75 per site. We assessed dietary intake using two separate 24-h recalls, body composition using bioelectrical impedance analysis, and health history, social and economic indicators by questionnaire. Blood pressure was measured and blood samples collected for measurement of lipids, glucose, insulin and adipokines. Full examination including physical activity using accelerometry, anthropometric data and fasting glucose will take place at 12 and 24 months. The distribution of the main variables and the associations between physical activity, independent of energy intake, glucose metabolism and anthropometric measures will be assessed using cross-section and longitudinal analysis within and between sites. DISCUSSION: METS will provide insight on the relative contribution of physical activity and diet to excess weight, age-related weight gain and incident glucose impairment in five populations' samples of young adults at different stages of economic development. These data should be useful for the development of empirically-based public health policy aimed at the prevention of obesity and associated chronic diseases.

Substrate metabolism, nutrient balance and obesity development in children and adolescents: a target for intervention?

Obesity results from the organism's inability to maintain energy balance over a long term. Childhood obesity and its related factors and pathological consequences tend to persist into adulthood. A cluster of factors, including high energy density in the diet (high fat intake), low energy expenditure, and disturbed substrate oxidation, favour the increase in fat mass. Oxidation of three major macronutrients and their roles in the regulation of energy balance, particularly in children and adolescents, are discussed. Total glucose oxidation is not different between obese and lean children; exogenous glucose utilization is higher whereas endogenous glucose utilization is lower in obese compared with lean children. Carbohydrate composition of the diet determines carbohydrate oxidation regardless of fat content of the diet. Both exogenous and endogenous fat oxidation are higher in obese than in lean subjects. The influence of high fat intake on accumulation of fat mass is operative rather over a long term. Several future directions are addressed, such that a combination of increased physical activity and modification in diet composition, in terms of energy density and glycemic index, is recommended for children and adolescents.

Stimulated sweating as a therapy to reduce interdialytic weight gain and improve potassium balance in chronic hemodialysis patients: a pilot study.

Controlling the extracellular volume in hemodialysis patients is a difficult task. The aim of this study was to evaluate the capacity of different methods of stimulated sweating to reduce mean interdialytic weight gain (IWG), to improve blood pressure regulation, and potassium/urea balance. Two center, crossover pilot study. In Lausanne, hemodialysis patients took four hot-water baths a week, 30 minutes each, on nondialysis days during 1 month. In Sfax, patients visited the local Hammam Center four times a week. Hemodynamic parameters were recorded, and weekly laboratory analysis was performed. Results were compared with a preceding 1-month control period. In Lausanne, five patients (all men, median age 55 years) participated. Bathing temperature was (mean ± standard deviation) 41.2 ± 3°C and sweating-induced weight loss 600 ± 500 g. Mean IWG (control vs. intervention period) decreased from 2.3 ± 0.9 to 1.8 ± 1 kg (P = 0.004), Systolic blood pressure from 139 ± 21 to 136 ± 22 mmHg (P = 0.4), and diastolic blood pressure form 79 ± 12 to 75 ± 13 mmHg (P = 0.08); antihypertensive therapy could be reduced from 2.8 ± 0.4 to 1.9 ± 0.5 antihypertensive drugs per patient (P = 0.01). In Sfax (n = 9, median age 46 years), weight loss per Hammam session was 420 ± 100 g. No differences were found in IWG or BP, but predialysis serum potassium level decreased from 5.9 ± 0.8 to 5.5 ± 0.9 mmol/L (P = 0.04) and urea from 26.9 ± 6 to 23.1 ± 6 mmol/L (P = 0.02). Hot-water baths appear to be a safe way to reduce IWG in selected hemodialysis patients. Hammam visits reduce serum potassium and urea levels, but not IWG. More data in larger patient groups are necessary before definite conclusion can be drawn.

Adipose tissue integrity as a prerequisite for systemic energy balance: a critical role for peroxisome proliferator-activated receptor gamma.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is an essential regulator of adipocyte differentiation, maintenance, and survival. Deregulations of its functions are associated with metabolic diseases. We show here that deletion of one PPARgamma allele not only affected lipid storage but, more surprisingly, also the expression of genes involved in glucose uptake and utilization, the pentose phosphate pathway, fatty acid synthesis, lipolysis, and glycerol export as well as in IR/IGF-1 signaling. These deregulations led to reduced circulating adiponectin levels and an energy crisis in the WAT, reflected in a decrease to nearly half of its intracellular ATP content. In addition, there was a decrease in the metabolic rate and physical activity of the PPARgamma(+/-) mice, which was abolished by thiazolidinedione treatment, thereby linking regulation of the metabolic rate and physical activity to PPARgamma. It is likely that the PPARgamma(+/-) phenotype was due to the observed WAT dysfunction, since the gene expression profiles associated with metabolic pathways were not affected either in the liver or the skeletal muscle. These findings highlight novel roles of PPARgamma in the adipose tissue and underscore the multifaceted action of this receptor in the functional fine tuning of a tissue that is crucial for maintaining the organism in good health.

Weights in the balance: jasmonic acid and salicylic acid signaling in root-biotroph interactions.

Work on the interaction of aerial plant parts with pathogens has identified the signaling molecules jasmonic acid (JA) and salicylic acid (SA) as important players in induced defense of the plant against invading organisms. Much less is known about the role of JA and SA signaling in root infection. Recent progress has been made in research on plant interactions with biotrophic mutualists and parasites that exclusively associate with roots, namely arbuscular mycorrhizal and rhizobial symbioses on one hand and nematode and parasitic plant interactions on the other hand. Here, we review these recent advances relating JA and SA signaling to specific stages of root colonization and discuss how both signaling molecules contribute to a balance between compatibility and defense in mutualistic as well as parasitic biotroph-root interactions.