When two people consume the same net calorie deficit, their resting metabolic rates and hormone levels may differ depending on how much total energy they are expending through activity and metabolism.

Even if two people eat the same low-calorie diet, their bodies might slow down metabolism differently — this study shows that people on calorie restriction often have different changes in resting metabolism, even when they lose the same amount of weight.

Even if two people eat the same number of calories and burn the same amount, how they burn those calories — like through exercise vs. just eating less — can change their metabolism and hormones differently. This study shows that adding exercise changes your body’s energy use in ways that eating less alone doesn’t.

Even if two people eat and burn the same number of calories overall, the one who exercises more and eats more tends to have a higher metabolism and feel less hungry—showing that how you spend your calories matters, not just the total.

Even if two people eat the same amount and burn the same calories overall, how they get there—like eating more and exercising more, or eating less and exercising more—can change how their bodies burn energy at rest. This study shows that the total amount of food and activity matters, not just the net calorie difference.

Even if two people eat and burn the same number of calories overall, the person who exercises more and eats more will have a higher metabolism and different body signals than someone who eats and exercises less—even if both are in the same calorie deficit.