Age-related impairments in the regulation of food intake

Low food intake in elderly individuals increases the risk for many nutrition-related acute or chronic illnesses. It is not known whether aging is associated with changes in hunger and satiety, or whether elderly individuals can regulate energy intake in response to manipulations of the energy or nutrient content of foods. Therefore, this study investigated short-term energy regulation in healthy elderly (n = 16; aged 60-84 y) and young (n = 16; aged 18-35 y) men. Participants were given yogurt preloads that varied in energy and macronutrient content (low-fat, low-energy, 962 kJ; high-fat, high-energy, 2134 kJ; high-carbohydrate, high-energy 2134 kJ), or no yogurt, followed by a self-selected lunch (presented 30 min after subjects began to consume the yogurt). Energy intake, the percentage of macronutrients consumed in the meals, and subjective sensations of hunger and satiety were analyzed. The elderly men consumed significantly less energy than the young men in the baseline (no yogurt) condition. Lower intake was concordant with subjective sensations of satiety; visual analog data indicated that the older men were less hungry and more full at the start of lunch. Compensation for energy in the preloads was less precise in the elderly than in the young men, in that elderly men consistently overate at the self-selected lunch. Young men consumed ± 10% total energy (lunch + yogurt) in the yogurt preload conditions compared with their baseline intake; elderly men overate between 10% and 30% in relation to their baseline intake. The proportions of macronutrients consumed in the test meals did not differ significantly across preload conditions or between the young and elderly participants. There were also no differences between the satiating effects of fat and carbohydrate. These results indicate that energy regulation is impaired in elderly individuals. Consuming an energy-dense nutritional supplement before a meal may be an appropriate strategy to increase energy and nutrient intakes in elderly people.