That’s a problem. It may explain why you are overweight.

Overweight? Part of the problem may be low vitamin D levels, a new study hints.

Among a group of 90 young women living in sunny southern California, those with insufficient levels of vitamin D were significantly heavier and had greater body mass than their counterparts with sufficient levels of vitamin D, Dr. Vicente Gilsanz, of Children’s Hospital Los Angeles and colleagues found.

It’s correlatory rather than causal, but still…