The study, to be published in the April issue of the International Journal of Obesity (vol 29, pp391-397), found obese people who cut back on their daily calorie intake for three months lost 22 per cent more weight if they ate low-fat yoghurt three times a day compared to those that only had one serving of dairy per day.
The results support previous findings linking dairy foods to lower weight. It is thought that the calcium in dairy foods plays a role in the body's fat absorption although the mechanism for this effect is still not clear.
Professor Michael Zemel from the University of Tennessee and colleagues randomly assigned 34 obese adults to one of two diet groups. All reduced their usual daily calorie intake by 500 calories but one group consumed only 400-500 mg of calcium per day while the other had an intake of 1100mg of the mineral via three servings of low-fat yoghurt.
Intake of dietary macronutrients and fibre were kept at average US levels.
Fat loss was markedly increased on the yoghurt diet - this group lost an average 4.43 kg compared to 2.75 kg in the control group.
The researchers saw particular benefits to fat around the 'trunk', a region where fat build-up is considered of high risk for development of heart disease and diabetes.
"Trunk fat loss was augmented by 81 per cent on the yoghurt vs control diet and this was reflected in a markedly greater reduction in waist circumference," write the researchers.
The calcium-rich diet helped the participants lose more than an inch around their waist, or an approximate six-fold greater decrease in waist circumference.
Zemel has previously reported that small changes in the calcium levels of fat cells alter signals within the cell that control the production and breakdown of fat. Calcium intake seems to trigger the body to burn more fat and reduces the amount of new fat the body makes.
Danish researcher Dr Arne Astrup has found another mechanism for calcium's effect on fat reduction, reported in the March issue of the same journal. Calcium could bind fat in the intestine and increase its excretion from the body, his results suggest.