RESUMO

INTRODUCTION: The determination of energy expenditure, considering the physical activity level and health status, is very important to adjust the individuals' nutritional supply. Energy expenditure can be determined by using indirect calorimetry, bioelectrical impedance, doubly labeled water, predictive equations, among others. All these methods have been used in clinical and research areas. However, considering the inconsistence in several research results, there is no consensus yet about the applicability of many of these methods. OBJECTIVES: The aim of this review is to describe the components of energy expenditure and the methods for its determination and estimation, summarizing their main advantages and limitations. RESULTS AND DISCUSSION: Indirect calorimetry and doubly labeled water are considered more accurate methods, but expensive. On the other hand, even though other methods present limitations, they are convenient and less expensive, and can be used with some caution.

Assuntos

RESUMO

OBJECTIVE: The maintenance of normal blood glucose concentrations is a crucial factor to the achievement of a good health status throughout life. However, the occurrence of abnormalities in this parameter has become increasingly common, which can result in several non-transmissible diseases, such as type 2 diabetes and cardiovascular diseases. Therefore, the purpose of this study was to discuss the role of protein sources in the glycemic and insulinemic responses. METHODS: In this review paper, we critically analyzed recently published studies that discussed the role of different protein sources in the glycemic and insulinemic responses in healthy individuals and in those who have cardiovascular diseases or type 2 diabetes. RESULTS: The results of some of these studies suggest that the daily ingestion of at least one high protein meal containing low to moderate amounts of carbohydrate increases insulin secretion and glucose uptake, improving insulin sensitivity. Furthermore, the results indicate that these effects are particularly associated with the consumption of animal protein (p.e. hydrolyzed whey protein), which has a high content of branched-chain amino acids such as leucine, valine and others such as arginine, which leads to improvements in insulin secretion and uptake glucose, since it increases insulin sensitivity. However, there is still no consensus in the literature about the quantity and quality of protein capable of reducing or maintaining blood-glucose concentrations at the desirable range, without causing adverse effects. The difference in the results of the studies may be associated to methodological problems presented by these studies. CONCLUSIONS: Well designed studies should be conducted to identify the quantity and quality of protein that can lead to the improvement on blood glucose concentrations, without negative effects to health. These studies should also identify the mechanisms and the magnitude by which protein may affect glycemic response.

Assuntos

RESUMO

The study investigates the effect of weight-maintaining high-sucrose (HSD) and high-fat (HFD) diets on plasma glucose and insulin concentrations in lean and obese women, and verifies the correlation between insulin profile and body composition. Lean (G1 group, n=6, BMI= 21.4 (20.2-22.8) kg/m2) and overweight/obese (G2 group, n=6, BMI 28.6 (25.1-32.1) kg/m2) women participated in the study. HSD (59% total carbohydrate with 23% sucrose; 28% lipid) or HFD (42% total carbohydrate with 1.3% sucrose; 45% lipid) diets were consumed under free-living conditions for 14 days. Anthropometry and body composition were assessed before and after HSD and HFD diets following-up. Fasting and postprandial (at 30, 60, 180 and 240 min) glucose and insulin were determined. HOMA-IR and QUICK index were also calculated. Fasting and postprandial glucose and insulin concentration did not differ significantly between groups or diets. However, there was a positive and significant correlation between plasma fasting and postprandial insulin concentrations and BMI, percentage of total body fat (% TBF) and HOMA-IR index. In addition, carbohydrate and sucrose intake presented a positive and significant correlation with insulin concentration and HOMA-IR at 180 min postprandial, after adjusting for energy intake and % TBF (p<0.05). These results suggest that altering the profile of the macronutrients in the diet can modify glycemia and insulinemia homeostasis, regardless of energy intake and adiposity. On the other hand, the overweight/obese women can maintain a stable metabolic profile with the habitual diet.

Assuntos

RESUMO

The diet composition can interfere directly in the energy homeostase. In the energy metabolism, the oxidation pathway and diet-induced thermogenesis are differentiated by diet macronutrients proportion. In this respect, the high-proteindiet is the most thermogenic, compared to high-carbohydrate and high-lipid diets, while high-carbohydrate diet appears to increase the thermogenic effect more than high-lipid diet, but the studies arecontroversies. Towards energy intake, it can stimulate or inhibit the energy intake, according to the foods palatability, satiation and satiety degree, related to diet carbohydrate, protein and lipid content. A hierarchy has been observed for the satiating efficacies of the macronutrients protein, carbohydrate and fat, with protein as most satiating and fat as least satiating. In general, there are discrepancies between studies about the regulatory role of macronutrients in the components of energy expenditure and intake, due the methodological differences in the subjects, exposition time for diet, energy density, and total energy content. The present work seeks to analyze the more consistent scientific evidences toward the modulator role of diet composition on the diet induced thermogenesis and energy intake, for better understanding of obesity prevention and control by dietetic intervention.

A composição da dieta pode interferir diretamente na homeostase energética. No metabolismo energético, a via de oxidação e a termogênese induzida pela dieta são diferenciadas pela proporção de macronutrientes da dieta. Neste sentido, a dieta hiperprotéica émais termogênica que as dietas hiperglicídicas e hiperlipídicas, enquanto que as dietas ricas em carboidrato parecem ser mais termogênicas que as ricas em lipídio, mas os resultados ainda são controversos. Em relação à ingestão calórica, a composição da dieta pode estimular ou inibir a mesma, de acordo com a palatabilidade dos alimentos e o grau de saciação e saciedade, relacionadas às quantidades de carboidrato, proteína e lipídio da mesma. Uma hierarquia tem sido relatada para a capacidade dos macronutrientes em induzir saciedade em que a proteína é o mais sacietógeno ao contrário dos lipidios, que são os menos sacietógenos. De modo geral, ainda há discrepâncias entre os estudos, em relação ao papel regulador dos macronutrientes em componentes do gasto energético e na ingestão calórica, devido às diferenças metodológicas como amostra, tempo de exposição à dieta, densidade calórica e conteúdo calórico total da mesma. Desta forma, o presente trabalho tem como objetivo analisar as evidências científicas mais consistentes a respeito do papel modulador da composição da dieta na termogênese induzida pela dieta e na ingestão calórica, para melhor entendimento da prevenção e controle da obesidade pela intervenção dietética.

Assuntos

RESUMO

OBJECTIVE: The purpose of this study was to investigate the effect of high sucrose diet (HD) and high fat diet (RFD) ingested under free-living conditions, on insulin homeostasis, verifies the association between insulin resistance and body composition as well. RESEARCH METHODS AND PROCEDURES: 20 healthy women, 13 normal-weight (22.5 +/- 2.1 years of age; BMI 22.2 +/- 1.9 kg/m2) and 7 over-weight (21.8 +/- 2.8 years of age; BMI 28.4 +/- 3.2 kg/m2), included in 2 groups G1 and G2 respectively, they were randomized to intake HD diets (59% carbohydrate including 23.0% of sucrose; 28.0% lipid; 13.0% protein; 20.2 g fiber) or HDF (42.0% carbohydrates including 1.3% of sucrose; 45.0% lipid; 13.0% protein; 22.2 g fiber) after initial assessment (BD). It was taken anthropometric measures, body composition and blood samples were obtained for fasting and post-prandial glucose and insulin determinations. RESULTS: Glycemia, insulinemia and HOMA-IR did not differ between groups (p > 0.05). Although on BD, HOMA-IR correlates positively with weight (r = 0.750), BMI (r = 0.929), waist circumference (WC) (r = 0.750) and percentage body fat (r = 0.857) for G2 group. The values of fasting HOMA-IR on BD were significantly greater than HFD for G1 group (p < 0.05). On HD the total carbohydrates amount and sucrose are greater than BD and HFD. CONCLUSION: The results confirm direct correlation between HOMA-IR, abdominal obesity and body fat. Therefore diet can modulate the insulinemic action.

Assuntos