Free CMWL Apples & Cinnamon Protein Oatmeal (Everyone’s Fav!), when you call or reply. Why CMWL? Reason#11: Vitamin D deficiency. Vitamin D has also been shown to help burn off the dreaded belly fat. A study from the University of Minnesota found that this nutrient triggers weight loss around the abdomen in particular. Authors of the study suggest that the vitamin works with calcium to reduce the production of cortisol, the notorious stress hormone that causes you to store belly fat.