Thermogenesis induced by a high-carbohydrate meal in fasted lean and overweight young men: insulin, body fat, and sympathetic nervous system involvement

Objective This dietary trial was designed to evaluate the effect of an experimental short-term fasting period followed by a high-carbohydrate meal on energy expenditure, thermogenesis, and sympathetic nervous system activity in normal (body mass index 27 kg/m2) men who were healthy, non-diabetic or with no other endocrine disease, non-smokers, not taking oral prescription medications, and with a stable body weight for the previous 3 mo. Methods Fasting and fed energy expenditures and diet-induced thermogenesis were measured after a high-carbohydrate meal in seven overweight and six lean young male subjects by indirect calorimetry. Heart rate, urinary excretion of catecholamines, serum glucose, and insulin were also measured over the experimental fasting (7.5 h) and postprandial (4 h) periods. Results After carbohydrate intake, overweight men showed a significantly higher energy production (kJ/kg of fat-free mass) than did lean individuals, and the diet-induced thermogenesis (percentage of energy intake) was positively correlated with body fat (kg), percentage of body fat, fat-free mass (kg), and fasting pre-meal serum insulin levels. Postprandial cumulative energy expenditure was directly associated with postprandial insulin response and with mean postprandial heart rate values. No significant differences in urinary catecholamines were found between lean and overweight men at basal conditions or during the study period. Conclusions Overweight individuals showed similar short-term sympathetic nervous system responses induced by an experimental fasting period. Although diet-induced thermogenesis after carbohydrate intake was not statistically different between lean and overweight men, the postprandial insulin response and body fat content seemed to be involved in sympathetic nervous system activity

Effects of leptin resistance on acute fuel metabolism after a high carbohydrate load in lean and overweight young men

Objective: Six lean (BMI = 20.8 ± 0.7) and seven overweight (BMI = 30.8 ± 1.7) young men (18–27 years old) were studied to investigate the acute effect of a high-carbohydrate meal on leptin levels and its relation to energy expenditure as well as to protein, carbohydrate and fat oxidation. Methods: Study participants were given a high-carbohydrate meal (17% as protein, 80% as carbohydrates and 3% as lipids) covering 40% of their estimated daily energy requirements. Serum leptin, insulin, glucose, free fatty acids and triglycerides levels were measured before meal intake and during the four postprandial hours. Furthermore, energy expenditure (EE), protein, carbohydrate and lipid oxidation were measured in fasted and fed conditions. Results: Fasting leptin was found to be positively correlated with circulating insulin concentrations (r = .748; p = 0.011) and body fat in kg (r = .827; p = 0.001). During the measured postprandial period no statistically significant changes were found in leptin levels as compared with pre-meal values in either lean or overweight men, nor differences in leptin changes between both groups. After load intake, carbohydrate oxidation was lower in overweight individuals (p < 0.05), while no significant differences were observed in protein oxidation. Cumulative lipid oxidation was found to be negatively associated with post-meal leptin values, being significantly lower in the overweight as compared with lean men (p < 0.05). This study demonstrates that the acute postprandial fuel substrate utilization is altered in overweight men with a lower carbohydrate oxidation and a strong inhibition of lipid oxidation, which could be attributed to some leptin resistance. Conclusion: These data also suggest that short-term meal-related metabolic responses may explain the long-term body adiposity if they are sustained over long intervals

Postprandial de novo lipogenesis and metabolic changes induced by a high-carbohydrate, low-fat meal in lean and overweight men

BACKGROUND: Adjustments of carbohydrate intake and oxidation occur in both normal-weight and overweight individuals. Nevertheless, the contribution of carbohydrates to the accumulation of fat through either reduction of fat oxidation or stimulation of fat synthesis in obesity remains poorly investigated. OBJECTIVE: The objective of this study was to assess the postprandial metabolic changes and the fractional hepatic de novo lipogenesis (DNL) induced by a high-carbohydrate, low-fat meal in lean and overweight young men. DESIGN: A high-carbohydrate, low-fat meal was administered to 6 lean and 7 overweight men after a 17.5-h fast. During the fasting and postprandial periods, energy expenditure (EE), macronutrient oxidation, diet-induced thermogenesis, and serum insulin, glucose, triacylglycerol, and fatty acids were measured. To determine DNL, [1-13C]sodium acetate was infused and the mass isotopomer distribution analysis method was applied. RESULTS: After intake of the high-carbohydrate meal, the overweight men had hyperinsulinemia and higher fatty acid and triacylglycerol concentrations than did the lean men. The overweight group showed a greater EE, whereas there was no significant difference in carbohydrate oxidation between the groups. Nevertheless, the overweight men had a marginally higher protein oxidation and a lower lipid oxidation than did the lean men. DNL was significantly higher before and after meal intake in the overweight men and was positively associated with fasting serum glucose and insulin concentrations. Furthermore, postprandial DNL was positively correlated with body fat mass, EE, and triacylglycerol. CONCLUSION: After a high-carbohydrate, low-fat meal, overweight men had a lower fat oxidation and a higher fractional hepatic fat synthesis than did lean men

Aspectos genéticos da obesidade

Obesity, defined as an excessive body fat accumulation, is caused by a chronic imbalance between energy intake and energy expenditure. Several factors have been associated with this energy imbalance, such as life style (diet and physical activity), neuroendocrine disorders, together with the genetic background. The genetic background is a major determinant factor of some congenital diseases and a risk factor for some chronic disorders, such as diabetes, osteoporosis, hypertension, cancer, obesity, and others. The increased prevalence of obesity in most countries during the last years, seems to indicate that there is a genetic predisposition or susceptibility to be obese which is increased by environmental and life style factors, mainly by food habits and physical in activity. The use of obesity animal models, genetic transfer and the association and linkage studies leaded to the identification of many genes associated with obesity

Establecimiento del tamaño de raciones de consumo de frutas y hortalizas para su uso en guías alimentarias en el entorno español: propuesta del Comité Científico de la Asociación 5 al día

Introduction: Food servings are standard amounts of food stuffs or drinks to help dietetic advice to promote and preserve health. The aim is to establish the serving size of fruits and vegetables (FH) to be used in food based dietary guidelines (FBDG). Material and Methods: Methodology of the United States Department of Agriculture (USDA) was adapted to establish serving sizes for FBDG, along of the followed by the food exchange system. Data was collected from the FH portion sizes reported in nutritional surveys and common sizes available in the Spanish market, and they were adjusted to an easily recognisable quantities of food with equivalence on key nutrients: the compliance with public health goals for FH consumption was evaluated. Results: Portion sizes typically reported in Spanish nutrition surveys are scarce and not homogeneous, and no data published in scientific journals on portion sizes were available. The Spanish FBDG, in spite of showing a range of serving size for FH, do not assure that they are interchangeable nor specify the method to obtein them.The serving of vegetables was 139,44g (DS:+/- 21.98, CV:0.16), 137,68g (DS:+/- 49,61, CV:0,36) for fruits and 28.00g (DS:+/- 7,53, CV:0.27) for dried fruits. Conclusions: With the established servings, the recommendation of consuming "at least 5 servings of FH a day" would allow reaching the Public Health goals for FH established in 600g (net weight)/person/day. It is recommended that the Spanish Agency for Consumers, Food Safety and Nutrition (AECOSAN) uses this methodology to establish serving sizes for the rest of food groups that make up the FBDG for the Spanish population.Introducción: Las raciones de consumo son cantidades estándar de alimentos o bebidas sugeri-das para asesorar sobre la cantidad de alimento a consumir para preservar un estado de salud adecuado. El objetivo principal de este trabajo es establecer los tamaños de ración de consumo de frutas y hortalizas (FH) para uso en guías alimentarias.Material y Métodos: Se adaptó la metodología de la United States Department of Agriculture (USDA) para el establecimiento de los tamaños de ración de consumo para guías, y la del Sistema de Intercambios. Se recopilaron datos de porción reportados en encuestas y calibres comunes en el mercado, se ajustó a cantidades de alimento fácilmente reconocibles y con equivalencia de nutrientes clave y se evaluó el grado de cumplimiento de los objetivos de salud pública para el consumo de FH. Resultados: Los tamaños de porción típicamente reportados en encuestas españolas son escasos y poco homogéneos, y no se encontraron datos publicados en revistas científicas sobre los cali-bres. Las guías alimentarias españolas, a pesar de mostrar un rango de tamaño de ración para FH no aseguran que sean intercambiables ni especifican el método para llegar a las mismas. La ración de hortalizas obtenida ha sido de 139,44g (DS:±21,98; CV:0,16), de 137,68g (DS:±49,61; CV:0,36) para frutas y 28,00g (DS:±7,53; CV:0,27) para frutas desecadas. . Conclusiones: Con las raciones establecidas, el mensaje “consume al menos 5 raciones entre FH al día” permitiría alcanzar los objetivo de Salud Pública para FH establecidos en 600g (peso neto)/persona/día. Se recomienda a la Agencia Española de Consumo, Seguridad Alimentaria y Nutrición (AECOSAN) que use esta misma metodología para el establecimiento de raciones en el resto de grupos de alimentos que configuran la Guía Dietética Basada en Alimentos para la población española

Sistema nervioso y obesidad

A pesar de las grandes variaciones diarias en la ingesta de nutrientes, las reservas de energía del organismo permanecen constantes en el tiempo, lo que sugiere la existencia de numerosos mecanismos reguladores de la adiposidad, el gasto energético y el apetito. La distensión gástrica, la absorción intestinal de nutrientes, las reservas lipídicas y de glucógeno, la tasa de utilización de substratos energéticos a escala central y periférica, la palatabilidad del alimento y otros factores psicológicos influyen en la regulación a corto plazo de la oxidación y el almacenamiento de macronutrientes, así como del apetito. Además, hormonas como la insulina y la leptina actúan más a largo plazo a nivel del cerebro, reduciendo la ingesta y aumentando el gasto energético. En dicho órgano, regulan importantes circuitos neuronales, sobre todo a nivel hipotalámico, que inician señales efectoras que controlan la homeostasis energética. Este trabajo estudia el papel del sistema nervioso central en la regulación del apetito y del balance energético.In spite of the great daily variations in the ingestion of nutrients, the energy reserves of the body remain constant over time, which suggests the existence of numerous mechanisms regulating adiposity, energy expenditure and appetite. Gastric distention, the intestinal absorption of nutrients, lipid and glycogen reserves, the rate of utilisation of energy substrates on a central and peripheral scale, the palatability of the food and other psychological factors, influence the short term regulation of oxidation and the storage of macronutrients, as well as appetite. Besides, hormones such as insulin and leptin act over the longer term on the brain, reducing ingestion and increasing energy expenditure. Important neuronal circuits regulate this organ, above all at the hypothalamic level, which initiate effector signals that control energy homeostasis. This paper studies the role of the central nervous system in the regulation of appetite and energy balanc

Sistema nervioso y obesidad

A pesar de las grandes variaciones diarias en la ingesta de nutrientes, las reservas de energía del organismo permanecen constantes en el tiempo, lo que sugiere la existencia de numerosos mecanismos reguladores de la adiposidad, el gasto energético y el apetito. La distensión gástrica, la absorción intestinal de nutrientes, las reservas lipídicas y de glucógeno, la tasa de utilización de substratos energéticos a escala central y periférica, la palatabilidad del alimento y otros factores psicológicos influyen en la regulación a corto plazo de la oxidación y el almacenamiento de macronutrientes, así como del apetito. Además, hormonas como la insulina y la leptina actúan más a largo plazo a nivel del cerebro, reduciendo la ingesta y aumentando el gasto energético. En dicho órgano, regulan importantes circuitos neuronales, sobre todo a nivel hipotalámico, que inician señales efectoras que controlan la homeostasis energética. Este trabajo estudia el papel del sistema nervioso central en la regulación del apetito y del balance energético.In spite of the great daily variations in the ingestion of nutrients, the energy reserves of the body remain constant over time, which suggests the existence of numerous mechanisms regulating adiposity, energy expenditure and appetite. Gastric distention, the intestinal absorption of nutrients, lipid and glycogen reserves, the rate of utilisation of energy substrates on a central and peripheral scale, the palatability of the food and other psychological factors, influence the short term regulation of oxidation and the storage of macronutrients, as well as appetite. Besides, hormones such as insulin and leptin act over the longer term on the brain, reducing ingestion and increasing energy expenditure. Important neuronal circuits regulate this organ, above all at the hypothalamic level, which initiate effector signals that control energy homeostasis. This paper studies the role of the central nervous system in the regulation of appetite and energy balanc

Thermogenesis induced by a high-carbohydrate meal in fasted lean and overweight young men: insulin, body fat, and sympathetic nervous system involvement

Objective This dietary trial was designed to evaluate the effect of an experimental short-term fasting period followed by a high-carbohydrate meal on energy expenditure, thermogenesis, and sympathetic nervous system activity in normal (body mass index 27 kg/m2) men who were healthy, non-diabetic or with no other endocrine disease, non-smokers, not taking oral prescription medications, and with a stable body weight for the previous 3 mo. Methods Fasting and fed energy expenditures and diet-induced thermogenesis were measured after a high-carbohydrate meal in seven overweight and six lean young male subjects by indirect calorimetry. Heart rate, urinary excretion of catecholamines, serum glucose, and insulin were also measured over the experimental fasting (7.5 h) and postprandial (4 h) periods. Results After carbohydrate intake, overweight men showed a significantly higher energy production (kJ/kg of fat-free mass) than did lean individuals, and the diet-induced thermogenesis (percentage of energy intake) was positively correlated with body fat (kg), percentage of body fat, fat-free mass (kg), and fasting pre-meal serum insulin levels. Postprandial cumulative energy expenditure was directly associated with postprandial insulin response and with mean postprandial heart rate values. No significant differences in urinary catecholamines were found between lean and overweight men at basal conditions or during the study period. Conclusions Overweight individuals showed similar short-term sympathetic nervous system responses induced by an experimental fasting period. Although diet-induced thermogenesis after carbohydrate intake was not statistically different between lean and overweight men, the postprandial insulin response and body fat content seemed to be involved in sympathetic nervous system activity

Dietas adelgazantes

Dietetic intervention has the following aims: to achieve a negative energy balance, obtain a healthy weight in the obese person and achieve the installation of healthy eating habits in order to maintain weight loss in the long term. Considering dietetic treatment of obesity as a process that is maintained for long periods of time, dietetic intervention should be carried out depending on the physio-pathological and psycho-social characteristics of the obese person. Besides, dietetic therapy should be balanced, healthy and adapted to the eating preferences of the patient. Over the years, due to need and the quest for rapid weight loss, magic diets have been occasioned, created and invented that have become popular and that lack proven efficacy and scientific rigour. This paper makes reference to a balanced hypocaloric diet and reviews the slimming diets that are best known and most used by the obese and/or overweight population.La intervención dietética tiene como objetivos: alcanzar un balance energético negativo, conseguir un peso saludable en la persona obesa y lograr la instauración de hábitos alimentarios saludables para mantener el peso perdido a largo plazo. Considerando el tratamiento dietético de la obesidad un proceso que se mantiene por largos periodos de tiempo, la intervención dietética deberá ser realizada en función de las características fisiopatológicas y psicosociales de la persona obesa. Además, la terapia dietética deberá ser equilibrada, saludable y adaptada a las preferencias alimentarias del paciente. A lo largo de los años, debido a la necesidad y búsqueda de una pérdida de peso rápida, se han originado, creado e inventado dietas mágicas que se han hecho populares y que carecen de eficacia comprobada y rigor científico. Este trabajo, hace referencia a la dieta hipocalórica equilibrada y revisa las dietas adelgazantes más conocidas y llevadas a cabo por la población obesa y/o con sobrepeso

Dietas adelgazantes

Dietetic intervention has the following aims: to achieve a negative energy balance, obtain a healthy weight in the obese person and achieve the installation of healthy eating habits in order to maintain weight loss in the long term. Considering dietetic treatment of obesity as a process that is maintained for long periods of time, dietetic intervention should be carried out depending on the physio-pathological and psycho-social characteristics of the obese person. Besides, dietetic therapy should be balanced, healthy and adapted to the eating preferences of the patient. Over the years, due to need and the quest for rapid weight loss, magic diets have been occasioned, created and invented that have become popular and that lack proven efficacy and scientific rigour. This paper makes reference to a balanced hypocaloric diet and reviews the slimming diets that are best known and most used by the obese and/or overweight population.La intervención dietética tiene como objetivos: alcanzar un balance energético negativo, conseguir un peso saludable en la persona obesa y lograr la instauración de hábitos alimentarios saludables para mantener el peso perdido a largo plazo. Considerando el tratamiento dietético de la obesidad un proceso que se mantiene por largos periodos de tiempo, la intervención dietética deberá ser realizada en función de las características fisiopatológicas y psicosociales de la persona obesa. Además, la terapia dietética deberá ser equilibrada, saludable y adaptada a las preferencias alimentarias del paciente. A lo largo de los años, debido a la necesidad y búsqueda de una pérdida de peso rápida, se han originado, creado e inventado dietas mágicas que se han hecho populares y que carecen de eficacia comprobada y rigor científico. Este trabajo, hace referencia a la dieta hipocalórica equilibrada y revisa las dietas adelgazantes más conocidas y llevadas a cabo por la población obesa y/o con sobrepeso