Listen to learn how your physical activity changes in response to a calorie surplus or a deficit. This is by far the most variable part of total daily energy expenditure, and it's a key part in explaining why some people find it harder to lose or gain weight than others.

Read more about metabolic adaptation here: Part One, Part Two

Read more about diet breaks and refeeds to mitigate metabolic adaptation here.

Read more about how many calories weight lifting actually burns here.