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Dietary Protein and Weight Gain
Abstract
To the Editor: When people overeat, diet composition should affect the amount of excess energy available for storage based on the difference in amount of adenosine triphosphate required for the initial steps of metabolism for each macronutrient. The intake of nutrients increases energy expenditure, in which the measured thermic effect is 0% to 3% for fat, 5% to 10% for carbohydrates, and 20% to 30% for proteins.1 The higher the protein content and the lower the fat content of a diet, the lower the net availability of energy for body functions including energy storage. Thus, it is surprising that Dr Bray and colleagues2 observed that protein content of the diet affected energy expenditure but not body fat storage. On the other hand, they stated that participants eating 40% more energy intake than required for weight stabilization stored 90% of the extra energy as fat when fed a low protein diet (containing 5% of energy from protein) and stored only about 50% of the excess energy as fat when fed a normal or high protein diet (containing 15% or 25% of energy from protein, respectively).
... Es por ello, que los alimentos cuyo aporte mayoritario son las grasas (principalmente de tipo monoinsaturado como el aceite de oliva), pueden ser muy eficaces para aumentar la ingesta energética y cantidad de alimentos (Westerterp and Kayser, 2006). Al contrario que con las proteínas, pues requieren más esfuerzo para ser digeridas, reducen el apetito (Acheson, 2011), producen saciedad (Veldhors, Westerterp et al. 2012) y han demostrado que ayudan en la pérdida de peso (Westerterp. 2012). ...
... de oliva), pueden ser muy eficaces para aumentar la ingesta energética y cantidad de alimentos (Westerterp and Kayser, 2006). Al contrario que con las proteínas, pues requieren más esfuerzo para ser digeridas, reducen el apetito (Acheson, 2011), producen saciedad (Veldhors, Westerterp et al. 2012) y han demostrado que ayudan en la pérdida de peso (Westerterp. 2012). Como norma general a altas altitudes nos podemos encontrar con las siguientes situaciones: ...
El alpinismo es una actividad física de gran arraigo en nuestro entorno, donde cada vez, más personas acuden
a realizar expediciones, la mayoría de ellos, sin experiencia. Existen varios factores en la montaña que
afecta a la salud nutricional de los alpinistas, como la deshidratación, hiponatremia, disminución del apetito y de la temperatura corporal. Estos factores pueden llevar a desencadenar una patología común en los alpinistas, el mal agudo de montaña, además de ser factores limitantes del rendimiento. Se estima entre
4500-6000kcal, las necesidades nutricionales a cubrir en la montaña, de las cuales el mayor % debe ser a raíz de hidratos de carbono de absorción rápida, a través de alimentos y bebidas fáciles de preparar, puesto que las condiciones ambientales así lo requieren. Se necesita preparar una estricta planificación dietética en la mochila, acorde al peso que los alpinistas puedan llevar en sus mochilas y los recursos que encontramos en los campamentos base y altura. Las expediciones se dividen en 4 fases en las que la planificación dietética será crucial, para cubrir las necesidades nutricionales y disminuir los problemas
asociados a los factores que limitan el rendimiento.
According to Lavoisier, 'Life is combustion'. But to what extent humans adapt to changes in food intake through adaptive thermogenesis - by turning down the rate of heat production during energy deficit (so as to conserve energy) or turning it up during overnutrition (so as to dissipate excess calories) - has been one of the most controversial issues in nutritional sciences over the past 100 years. The debate nowadays is not whether adaptive thermogenesis exists or not, but rather about its quantitative importance in weight homoeostasis and its clinical relevance to the pathogenesis and management of obesity. Such uncertainties are likely to persist in the foreseeable future primarily because of limitations to unobtrusively measure changes in energy expenditure and body composition with high enough accuracy and precision, particularly when even small inter-individual variations in thermogenesis can, in dynamic systems and over the long term, be important in the determining weight maintenance in some and obesity and weight regain in others. This paper reviews the considerable body of evidence, albeit fragmentary, suggesting the existence of quantitatively important adaptive thermogenesis in several compartments of energy expenditure in response to altered food intake. It then discusses the various limitations that lead to over- or underestimations in its assessment, including definitional and semantics, technical and methodological, analytical and statistical. While the role of adaptive thermogenesis in human weight regulation is likely to remain more a concept than a strictly 'quantifiable' entity in the foreseeable future, the evolution of this concept continues to fuel exciting hypothesis-driven mechanistic research which contributes to advance knowledge in human metabolism and which is bound to result in improved strategies for the management of a healthy body weight.
The role of diet composition in response to overeating and energy dissipation in humans is unclear.
To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition.
A single-blind, randomized controlled trial of 25 US healthy, weight-stable male and female volunteers, aged 18 to 35 years with a body mass index between 19 and 30. The first participant was admitted to the inpatient metabolic unit in June 2005 and the last in October 2007.
After consuming a weight-stabilizing diet for 13 to 25 days, participants were randomized to diets containing 5% of energy from protein (low protein), 15% (normal protein), or 25% (high protein), which they were overfed during the last 8 weeks of their 10- to 12-week stay in the inpatient metabolic unit. Compared with energy intake during the weight stabilization period, the protein diets provided approximately 40% more energy intake, which corresponds to 954 kcal/d (95% CI, 884-1022 kcal/d).
Body composition was measured by dual-energy x-ray absorptiometry biweekly, resting energy expenditure was measured weekly by ventilated hood, and total energy expenditure by doubly labeled water prior to the overeating and weight stabilization periods and at weeks 7 to 8.
Overeating produced significantly less weight gain in the low protein diet group (3.16 kg; 95% CI, 1.88-4.44 kg) compared with the normal protein diet group (6.05 kg; 95% CI, 4.84-7.26 kg) or the high protein diet group (6.51 kg; 95% CI, 5.23-7.79 kg) (P = .002). Body fat increased similarly in all 3 protein diet groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure, total energy expenditure, and body protein did not increase during overfeeding with the low protein diet. In contrast, resting energy expenditure (normal protein diet: 160 kcal/d [95% CI, 102-218 kcal/d]; high protein diet: 227 kcal/d [95% CI, 165-289 kcal/d]) and body protein (lean body mass) (normal protein diet: 2.87 kg [95% CI, 2.11-3.62 kg]; high protein diet: 3.18 kg [95% CI, 2.37-3.98 kg]) increased significantly with the normal and high protein diets.
Among persons living in a controlled setting, calories alone account for the increase in fat; protein affected energy expenditure and storage of lean body mass, but not body fat storage.
clinicaltrials.gov Identifier: NCT00565149.
The intake of nutrients is known to increase energy expenditure. Measured thermic effects of nutrient are 0-3% for fat, 5-10% for carbohydrates and 20-30% for proteins. Stimulation of adenosine triphosphate (ATP) hydrolysis during intestinal absorption, initial metabolic steps and nutrient storage are responsible for this food thermic effect. The autonomic nervous system modulates the thermic effect of nutrients. Parasympathetic muscarinic antagonists reduce the thermic effect of orally administered nutrients, most likely by delaying gastric emptying and decreasing the amount of nutrient storage. Antagonists of the beta-adrenoreceptors decrease the thermic effect of glucose. The part of glucose induced thermogenesis which is eliminated by beta-adrenergic antagonists has been called 'facultative thermogenesis' and takes place, at least in part, in skeletal muscle. Insulin-induced stimulation of muscle sympathetic nerve activity may be involved in this facultative thermogenesis. The thermic effect of food is reduced in obese, insulin-resistant patients. The effect of thermogenesis represents about 50-150 kcal/day in such patients, and can explain only a minor part of their excess body weight. Defective thermogenesis may, however, contribute to weight gain, or impair weight loss in such patients.
Assessment of body composition in relation to the habitual diet and after a six month dietary intervention.
After a baseline measurement subjects were randomly assigned to either a group consuming reduced-fat products or a group consuming full-fat products for six months.
108 women and 109 men, equally distributed over the age range 19-35 with BMI between 21 and 28, and the age range 36-55 with BMI between 24 and 30.
Food intake was measured by three day dietary record, body composition by deuterium dilution.
At baseline, explained variance of %body fat on age and fat-carbohydrate ratio in the diet together were 17% (P < 0.0001) and 36% (P < 0.0001) for women and men, respectively, and on diet alone 7-8% (P < 0.01) independent of gender. The diet intervention caused on average a change in fat intake and body fat mass in subjects of the reduced-fat group of -5 +/- 29 g/d (P < 0.05) and -0.1 +/- 2.1 kg (ns), respectively, and of +23 +/- 31 g/d (P < 0.0001) and +0.5 +/- 2.3 kg (P < 0.05) in subjects of the full-fat group. The change in the fat content of the diet was positively related to a change in energy intake (fat-carbohydrate ratio: R2 = 0.15, P < 0.0001; g fat: R2 = 0.70, P < 0.0001), the latter explaining 5% of the variation in the change in body fat mass (P < 0.001). Subjects changing the fat content of the diet showed a consequent change in body fat mass only when energy intake changed as well.
The fat content of the diet has an effect on body fat as a function of the effect of dietary fat on energy intake.