Changes of Body Mass and Energy Balance during Fasting and Dietary Restriction
Introduction The energy balance of the body depends upon a close matching of energy intake to energy expenditure; even a small but repeated discrepancy can have major consequences over the course of several months. If energy expenditure is greater than
energy intake, there will inevitably be a decrease of body mass; on the contrary, if energy intake is greater than energy expenditure, body mass will necessarily increase. However, it is important to underline that a calculation of energy balance does not indicate the nature of the associated change in body composition; there may be gains or losses of both fat and lean tissue, determined in part by the type of nutriments ingested. Increases of carbohydrate and proteins intake favour the stimulation of their oxidation, whereas a greater fat intake predisposes to both fat storage in adipose tissue and also an increase in the oxidation of fat .