Does Vitamin D Deficiency Really Cause Obesity?

Even if there were a strong relationship between obesity and vitamin D2 levels, and there's not, this wouldn't mean that vitamin D deficiency caused obesity so taking vitamin D supplements would help you lose weight. There would be at least two different ways to understand the data:

1. One would be that low vitamin D levels somehow stuffed fat into your fat cells.
2. The other would be that you didn't like to lie out by the pool so you didn't get as much sun!

Or that you were less able to spend time outdoors, especially in hot, sunny weather, because the heat made you uncomfortable and you didn't get as much sun.

There is one important principle to remember about weight gain. While there are many factors that affect your appetite, and there are many factors that accelerate or decelerate weight gain or weight loss,

You lose weight when you eat less, and you gain weight when you eat more.

If you want to weigh less, chances are you aren't going to be able to exercise enough to make a big difference on the scales. You really will, at some point, have to eat less. The question is how much less.
Will vitamin D help you lose weight faster or gain weight more slowly?

There is some exciting news. Researchers really have answered the question of whether vitamin D helps women lose weight after menopause. A group of researchers at Creighton University Medical Center in Omaha, Nebraska followed 1,179 women for four years, giving them combinations of calcium and vitamin D. One group got Calcium plus a fake vitamin pill. One group got Calcium plus a real vitamin D pill. And one group got two fake supplement pills. All were followed for four years. One group got a boost in weight-loss dieting. Which group was it?