Social and physiological factors affecting food intake in elderly subjects: an experimental comparative study

The decline in average food intake in elderly people is attributed to both physiological and social factors. These factors are usually studied in isol ation. The present study concerns an experiment in which the effect of soci al setting on food intake is compared with the effect of physiological chal lenges on food intake in 24 elderly subjects (6 men and 18 women, age: 75+/ -4.9 years, BMI = 26.6+/-3.5 kg/m(2)). Physiological effects were assessed using a preload-test-meal design with a no load, 0 kJ; and 4 preload condit ions: low carbohydrate/low fat, low energy, 0.4 MJ; high fat, low carbohydr ate, medium energy, 1.1 MJ; high carbohydrate, low fat, medium energy 1.1 M J; high fat, high carbohydrate, high energy, 1.8 MJ. The preloads consisted of 300 g of strawberry yogurt drink, and were served at 10:00 a.m. The tes t-meal, served 90 min after the preload consumption, was a lunch of which s ubjects could eat ad libitum. Social effects on food intake were assessed b y using two social settings at lunchtime: cozy and non-cozy. Dependent vari ables were food intake at lunch and ratings of appetite assessed before the preload, and between preload and test-meal. Results showed that energy int ake at lunch was significantly decreased after the high carbohydrate preloa d and the high fat-high carbohydrate preload (intake compensation of 23 and 15%, respectively), compared to the no preload condition. The other preloa ds did not have a significant effect on food intake. Energy intake was of 2 .5+/-0.5 MJ in the cozy social setting and of 2.5+/-0.6 MJ in the non-cozy one. Appetite feelings were generally lower after the preload conditions co mpared to the no load condition (P<0.05), but there were no significant eff ects of the macronutrient or energy content of the preloads on appetite fee lings. It is concluded within the context of this study in healthy elderly subjects that food intake responds more to physiological challenges than to short-term changes in social settings. (C) 2000 Elsevier Science Ltd. All rights reserved.