Drinking two glasses of milk regularly could help you shed nearly six kilograms of weight. The role of dairy calcium intake and serum vitamin D concentrations in weight loss is controversial though it is known that over-weight people have lower levels of serum vitamin D. Vitamin D increases calcium absorption in the bloodstream and in addition to sun exposure can be obtained from fortified milk, fatty fish and eggs. The recommended daily requirement of Vitamin D is 400 international units, which is found in four glasses of milk.
To explore the association of dairy calcium intake and serum vitamin D with weight loss, researchers followed 322 overweight men and women in Israel aged 40-65 years, who were asked to follow either low-fat, low-carbohydrate or Mediterranean diets for two years.
It was found that participants with the highest dairy calcium intake six months into the study (averaging about 580 mg daily- the amount in nearly two glasses of milk) lost about six kilograms at the end of the two years, compared to about 3.5 kg for those with the lowest dairy calcium intake (averaging about 150 mg, or about half of a glass). Beyond calcium, it was also found that vitamin D levels independently affected weight loss success, its level in the blood rising in those who lost more weight.
The study suggests that both higher dairy calcium intake and increased serum vitamin D are related to greater diet-induced weight loss.