EXERCISE-TRAINING, MACRONUTRIENT BALANCE AND BODY-WEIGHT CONTROL

It is well established that exercise-training can induce body weight a nd fat losses provided that mean daily energy expenditure exceeds mean energy intake. Recent experimental data show that under free living c onditions, the composition of macronutrient intake tends to differ fro m the composition of macronutrient utilization when the body is in ene rgy imbalance, even over a short period of time, Since protein and car bohydrate balances are precisely regulated under unrestricted food int ake conditions, a body energy deficit is necessarily equivalent to a l ipid deficit, In the context of an aerobic training program, a body li pid deficit should be spontaneously reached by performing prolonged vi gorous exercise on a regular basis and by preventing a diet with a hig h fat content. However, as body fat decreases with exercise there is a n associated decrease in the lipid content of the fuel mix oxidized an d this acts to progressively decrease the lipid deficit, Ultimately, a new lipid balance will be reached at a reduced level of body fatness when the proportion of lipid in the substrate mix will become similar to the proportion of lipid in the diet, Recent research observations s how that such a program has the potential to induce a substantial fat loss, particularly in the abdominal area, and a significant improvemen t of the metabolic profile of obese individuals, These beneficial effe cts cannot be maintained on a long-term basis if the new exercise and food habits are not incorporated in the lifestyle of these individuals .It is well established that exercise-training can induce body weight and fat losses provided that mean daily energy expenditure exceeds mea n energy intake. Recent experimental data show that under free living conditions, the composition of macronutrient intake tends to differ fr om the composition of macronutrient utilization when the body is in en ergy imbalance, even over a short period of time, Since protein and ca rbohydrate balances are precisely regulated under unrestricted food in take conditions, a body energy deficit is necessarily equivalent to a lipid deficit. In the context of an aerobic training program, a body l ipid deficit should be spontaneously reached by performing prolonged v igorous exercise on a regular basis and by preventing a diet with a hi gh fat content. However, as body fat decreases with exercise there is an associated decrease in the lipid content of the fuel mix oxidized a nd this acts to progressively decrease the lipid deficit, Ultimately, a new lipid balance will be reached at a reduced level of body fatness when the proportion of lipid in the substrate mix will become similar to the proportion of lipid in the diet. Recent research observations show that such a program has the potential to induce a substantial fat loss, particularly in the abdominal area, and a significant improveme nt of the metabolic profile of obese individuals, These beneficial eff ects cannot be maintained on a long-term basis if the new exercise and food habits are not incorporated in the lifestyle of these individual s.