Exercise, Food Intake and Body Weight in Normal Rats and Genetically Obese Adult Mice

Effects of physical activity on food intake

“…The findings support the first results presented by Mayer et al 6 on suppressed dietary intake with introduction of acute PA (Fig. 1, zone 2).…”

“…6,7 An important aspect of the maintenance of energy balance during high-intensity endurance exercise is an adjustment of food intake to high-energy requirements. An example of daily energy intake in endurance, strength, and team sport athletes are presented in Table 1.…”

“…Mayer et al 6,7 performed several of the earlier studies, on both animals and humans, examining the effect of exercise on body mass and food intake. To the extent that it is legitimate to draw an equivalence between purely experimental results and the results of population studies, a remarkable parallelism was found between the two.…”

“…6 It was observed that an introduction of short periods of exercise (1 h or less/day) in the life of normal rats were not followed by an increase in food intake over the amount corresponding to absolute inactivity. In fact, a significant decrease in food intake occurred indicating a probable greater availability of endogenous fuel mobilization due to enhanced vascularization of body tissues.…”

“…In fact, a significant decrease in food intake occurred indicating a probable greater availability of endogenous fuel mobilization due to enhanced vascularization of body tissues. 6 As a result, the mass of the animals Figure 1 A model showing the relationship between Physical Activity Level (PAL), body mass and food intake; zone 1: decrease in PAL and increase in sedentariness does not induce compensatory reduction in food intake and leads to increase in body mass; zone 2: introduction of acute physical activity on a short-term basis suppresses food intake, due to mobilization of stored fuels, and leads to decrease in body mass; zone 3 (responsive range): moderate to intense physical activity performed regularly and on a long-term basis by lean individuals increases food intake accordingly and maintains body mass; obese individuals, due to their excess energy storage, do not show significant changes in food intake; the PAL level in the general population has an upper limit around 2.2-2.5 (zone 4), and in highly trained subjects around 4.0-5.0 (zone 5). Above these values, the human body is not capable to cover the high-energy expenditure, and loss of body mass occurs as a consequence.…”