식품의 선택과 비만증과의 관계에 관한 고찰

A Relation between Food Selection and Obesity

  Researchers have carried out experimental and clinical investigations on the food consumption and body weight regulation in order to throw light upon mechanisms which may contribute to human obesity, the accumulation of excess body fat. Mechansms underlying food selection clearly depend on the regulation of macronutrients. When animals are given a choice of isocaloric diets, they can regulate either protein or carbohydrate intake.   A number of dietary constituents can affect central metabolism. All neurotransmitters whose syntheses are known to be influenced by precursor availability are produced from compounds that must be obtained in whole or in part from the diet. With regard to food selection, the important precursor is tryptophan which is synthesized to serotonin. Serotonin-releasing brain neurons are markedly affected by the composition of the diet: consumption of a carbohydrate-rich, portein-poor meal increases brain serotonin synthesis by increasing brain levels of tryptophan. Consumption of a high-protein meal has the opposite effect, decreasing both brain tryptophan levels and serotonin synthesis. Also, such serotoninergic drugs as fenfluramine, fluoxetine, and CGS 10686B decreased consumption of the high-carbohydrate diet but not the one with the lower carbohydrate content and higher protein/carbohydrate ratio. These results indicate that brain serotonin might be involved in a complex behavioral feedback loop in which the consumption of a high-carbohydrate meal enhances serotonin-mediated neurotransmission which, in turn, causes the animal to decrease its intake of carbohydrate during the next meal.   The ratio of carbohydrate to protein can predict the development of dietary obesity because the ratio showed positive relation with the percentage of body water and inverse relation with body weight gain and the percentage of body fat. Larger consumption of protein than required would also affect the onset of obesity.