Vitamin D deficiency is 35 percent higher than normal in obese people, and 24 percent higher in over-weight people – according to a meta- analysis by brazilian researchers. Vitamin D deficiency can make it difficult to lose weight. The initial vitamin D level is a good predictor of weight loss during calorie restriction. People with low vitamin D levels have difficulty losing weight, while those with those with the highest levels lost the most weight. People should get 400-800 units of vitamin D from the diet, supplements or sun exposure. Low vitamin D levels are a problem in many people because they spend much of their time indoors and shun vitamin D-fortified milk in favor of other beverages.
(Obesity Reviews, 16: 341-349, 2015)