Question

Historically, it has been believed that a cumulative energy deficit of 3500 kcal results in a loss of 1 pound of fat. However, new research reveals that this "rule of thumb" does not precisely predict fat weight loss during weeks-to-months of a low-calorie diet. This failure of the "3500 kcal rule" to accurately predict weight loss is due to:

a. all of these are correct.
b. the 3500 kcal rule does not consider that weight loss results in a lower resting metabolic rate.
c. this rule does not take into account that numerous physiological changes in the body occur during weight loss.
d. 3500 kcal rule does not take into account that the energy cost of physical activity decreases following weight loss.

Answer 1

The failure of the "3500 kcal rule" to accurately predict weight loss is due to a combination of factors, including changes in metabolic rate and the energy cost of physical activity.

Step-by-step explanation:

The failure of the "3500 kcal rule" to accurately predict weight loss is due to several factors. One of the main reasons is that the rule does not consider the physiological changes that occur in the body during weight loss. These changes can affect the resting metabolic rate and the energy cost of physical activity, making it difficult to accurately predict fat weight loss based solely on calorie deficit.

For example, when someone loses weight, their resting metabolic rate may decrease, meaning they burn fewer calories at rest compared to before weight loss. Additionally, the energy cost of physical activity may decrease as well. So even if someone maintains a consistent calorie deficit, the rate at which they lose fat may not align with the expected 3500 kcal per pound.

Overall, the failure of the "3500 kcal rule" to accurately predict weight loss is due to a combination of factors, including changes in metabolic rate and the energy cost of physical activity.