Men who had excess belly fat saw their vitamin D levels go up by 27% after a year of eating better and moving more—even though they didn’t take any vitamin D pills or supplements.

When overweight men lose body fat through lifestyle changes like diet and exercise over a year, their vitamin D levels go up by about 27% and their leptin (a hunger hormone) levels drop by 27%—and these two changes seem to be connected, even after accounting for how much fat they lost in different parts of their body.

In men who carry extra fat around their belly, when their vitamin D levels go up or down, their leptin levels (a hormone that affects hunger) also change — even when you account for how much fat they have in different parts of their body.

If a man with excess belly fat eats less and moves more for a year, his belly fat, hunger hormone levels, and vitamin D levels all get better.

If overweight men lose a lot of belly fat over a year by eating better and moving more, their hunger hormone (leptin) goes down and their vitamin D levels go up — both by about a quarter.

Your body needs to digest fats properly to absorb vitamin D from food—like how oil helps dissolve and carry the vitamin into your bloodstream.