The science behind dairy and weight loss
Evidence is emerging that dietary calcium, particularly from dairy foods, may alter the way fat cells function and a high-calcium intake seems to offer protection against excess body weight and fat gain in adults and children.
An association between calcium and body weight was first noted about 20 years ago - somewhat by accident. A clinical trial investigating the effects of calcium on blood pressure on obese African-Americans, found that those whose diets were supplemented with two cups of yogurt a day lost 4.9kg body fat in a year.
The same scientists tested animals with a high-calcium diet against a low calcium diet and also found that glucose and insulin levels went down and they gained less body weight.
These findings prompted a re-examination, in 2000, of data from previous investigations to see whether calcium had a real ink with changes in body weight. The researchers looked back over 12 years of research and a total of 780 women, aged 20 to 70, and were examined. In a two-year study. They also investigated the effects of calcium intake on changes in body composition in women aged 18 to 31.Thirty-two obese women were fed one of three different low-energy diets (500 calories lower than estimated daily energy needs) for twenty-four weeks.
They were given randomly one of three diets which were:
- Low calcium/low dairy diet with 400mg - 500mg calcium per day
- Low calcium/low dairy diet supplemented with 800mg calcium per day
- A diet containing three servings per day of low-fat dairy foods, to provide 1,200mg to 1,300mg of calcium (i.e. a high-calcium dairy diet)
The investigators found that:
- Group 1 lost 6.4% of their bodyweight (19% trunk loss)
- Group 2 lost 8.1% of their bodyweight (50% trunk loss)
- Group 3 lost 10.9% of their bodyweight (66% trunk loss)
Researchers also found that children with a low intake of milk and dairy products are more likely to be overweight and have a higher percentage of body fat than those with a higher dairy intake.