Why Hormones Matter More Than Calories for Some People Calories in vs calories out is real — thermodynamics cannot be violated. But hormones determine where those calories go, how efficiently your body burns fat vs muscle, how hungry you feel at a given calorie intake, and where on your body fat is preferentially stored and stubbornly held. Two people eating identical diets can have dramatically different fat loss outcomes because of hormonal differences. This is not an excuse — it is a lever. Consider this: a person with insulin resistance will struggle to access stored fat for energy ev…