A recent editorial in the journal Obesity addressed common misconceptions about obesity. The author covered twenty-two points. Number nine was particularly interesting: “Although less obvious than the fact that energy intake must be equal to energy expenditure, weight stability also requires that the substrate mixture oxidized must be equivalent, on average, to the composition of the nutrient mix consumed.”
Put another way, over any extended period of time, during which one’s weight and body composition (percent fat, muscle, etc.) are stable, the amount of carbohydrate, protein and fat “burned” by metabolism must be equal to the amounts of these nutrients consumed in the diet.
This has practical implications. If one consumes a diet high in fat, one must also metabolize fat at the same average rate. There are three common ways that fat metabolism is stimulated:
- depletion of the body’s glycogen (carbohydrate) stores
- increase in the body’s fat stores.
Therefore, under any constant set of conditions, including exercise/activity and eating habits, one’s percent body fat will be a reflection of the amount of fat in the diet.