Running

Even for fit runners, the assumption that more running equals more fat burning is incorrect regardless of fitness level. The additional calories burned while running come predominantly from glucose, not fat, making the calorie advantage illusory for fat loss. Running triggers the hormonal environment — cortisol and insulin elevation — that directly prevents fat loss. Post-run hunger consistently leads to increased food intake that often fully offsets the calorie deficit. Running is appropriate but not for fat loss as the primary goal; it suits people who are already fit and insulin sensitive.