Obesity, diet and body temperature

Abstract

Studies conducted thus far on the pathogenesis of obesity have not clearly determined the role of body temperature in the energy balance. In an attempt to explore this relationship further, research has been undertaken, a part of which is represented by the present investigation carried out on 22 adult males: 11 having a BMI less than or equal to 25 (group A) and 11 with BMI greater than 25 (group B). Body temperature was measured by mouth and on the skin surface (in 4 points according to Ramanathan) on 2 consecutive days (every 30 min from noon to 6:30 p.m.), the 1st day with the participants fasting and the 2nd day after consumption of a meal whose energy content represented a part (45%) of the 24-hour energy intake of the subjects, as previously ascertained by a survey of their food consumption. The study was carried out under frequently checked microclimatic conditions. During the week prior to the measurements, the alimentary consumption of the subjects was monitored by direct weighing for 5 consecutive days. A significant rise in body temperature, probably due to dietary thermogenesis, was observed in group A (internal temperature: F = 13.05; skin temperature: F = 6.48) as well as in group B (internal temperature: F = 24.88; skin temperature: F = 5.35) after the meal. However in group B the skin temperature showed a smaller increase than in group A (delta t degree 0.31 vs. 0.49) and an earlier trend towards the basal values (nearly 5 vs. 6 h after the meal). In both groups a decrease in the skin delta t degrees is evident at 3 and 3.5 h, respectively, after the meal, followed by a more remarkable increase in this difference between the 4th and the 5th hour. The meaning of this decrease as well as the difference in body temperature versus caloric intake is discussed. Normal weight individuals demonstrated a positive correlation (r = 0.83) between usual caloric intake per square meter of body surface and fasting internal body temperature. This correlation was not observed in subjects with BMI greater than 25