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.

In men taking 2000 IU of vitamin D daily for 12 weeks, blood levels of vitamin D rise more when their diet is high in fat than when it is high in carbohydrates.

If your pancreas isn't making enough digestive juices, taking vitamin D pills won't help because your body can't absorb the vitamin properly—it needs fat to soak it up, and your pancreas isn't helping with that.

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.

Having more vitamin D in your body might help you build more muscle and store less fat, directing your body’s energy toward making lean tissue instead.

Even though people ate more dairy, their body didn’t make more of the active form of vitamin D—so the hormone that might affect fat cells stayed the same.