Question

Exercise training combined with caloric restriction results in a greater weight loss than diet alone. The physiological explanation for this observation is that:

a. exercise training might promote the conversion of white fat cells to beige fat cells.
b. all of these are correct.
c. exercise can preserve lean body mass resulting in protection against a decrease in resting energy expenditure.
d. exercise increases the energy expenditure side of the energy balance equation.

Answer 1

Greater weight loss from exercise combined with dieting is achieved due to increased metabolic activity from muscle preservation and energy expenditure during while performing physical activities, as well as the conversion of white to beige fat cells.

Step-by-step explanation:

Exercise training combined with caloric restriction results in greater weight loss than diet alone because it involves two main physiological effects. First, exercise can promote the conversion of white fat cells to beige fat cells which are more metabolically active. Second, exercise helps preserve lean body mass, which is critical in maintaining resting energy expenditure (REE) or basal metabolic rate (BMR), meaning more calories burnt even during rest. Additionally, exercise increases overall energy expenditure by working the muscles and generating heat.

Living systems are not always simple, and the body's response to energy intake and energy expenditure can change, especially after repeated diets. With a lower energy intake, the body may lower its BMR, making weight loss slower. Combining exercise with dieting counteracts this by burning off extra calories and building lean tissue which is more metabolically demanding, thus increasing the BMR and enhancing weight loss. This also highlights why exercise alone may not be sufficient to lose weight as the caloric expenditure from exercise must surpass the energy intake from food.