How does metabolism change during weight loss?

The correct answer highlights a key physiological response during weight loss: metabolism may decrease due to the loss of lean body mass. As individuals lose weight, especially if the weight loss is rapid or not adequately supported by strength training and adequate protein intake, there is often a reduction in muscle mass. Lean body mass is metabolically active, meaning it requires energy to maintain. When muscle mass decreases, the overall resting metabolic rate can decline, leading to a slower metabolism.

This mechanism is a significant consideration in weight management because a lower metabolic rate can make it more challenging to continue losing weight or maintain weight loss in the long term. It emphasizes the importance of incorporating strength training and ensuring proper nutrition to preserve muscle mass during the weight loss process.

In contrast, while metabolism does increase in response to certain factors (such as exercise) or in the short term after a calorie deficit, the long-term effects of significant weight loss typically involve a decrease in metabolic rate associated with diminished lean body mass. Thus, this answer accurately reflects the physiological changes that occur during weight loss.