Supplementing with vitamin D can increase the rate of weight loss during dieting. Those with high blood levels of vitamin D achieved triple the weight loss of those with low levels of the vitamin.
The groups received either a high vegetable diet or a high cereal grain diet. Both groups lost weight, but the effect of vitamin D was only achieved in the high cereal grain diet… indicating that at least part of the benefit results from improved insulin sensitivity.
Optimal vitamin D levels can only be achieved through supplementation or sun exposure.