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Dairy and Weight Loss

Zemel , MB , Thompsom, W, Milstead, A, Morris, K, and Campbell, P. Calcium and dairy acceleration of weight and fat loss during energy restriction in obese adults. Obesity Research 2004;12:582-590.

Epidemiological data from NHANES (1) and the CARDIA (2) studies, among others, have shown that increased dietary calcium intake is associated with greater weight and fat loss in humans, and that when dietary calcium is derived from dairy products, weight and fat loss is greater than with supplements alone.

In a recent randomized, controlled clinical trial, researchers found that an increase in calcium intake did seem to cause greater weight loss than those with lower amounts of calcium in their diet.

Study details:

41 healthy, obese adults were enrolled for 24 weeks and randomized into one of 3 different groups:

•  Control diet

•  500 kcal deficit, zero to one serving of dairy, 400-500 mg of calcium, and a placebo supplement.

•  High-calcium diet

•  Included the control diet plus an 800 mg calcium supplement, to provide 1200-1300 mg of calcium per day.

•  High-dairy diet

•  Included the control diet plus 3 servings of dairy products per day, to provide 1200-1300 mg of calcium per day, and a daily placebo supplement.

Thus, the high-calcium diet and the high dairy diet included the same amount of calcium, but differed in the source of the calcium - the high-calcium diet received calcium from a supplement, while the high-dairy diet received its calcium from dairy products. This distinction allows the researchers to separate the effects of supplemental calcium and calcium from dairy products.

Two primary outcomes were measured:

Body weight - measured by a calibrated scale, measured weekly

Fat loss - measured by a Dual Energy X-Ray Absorptiometry (DXA) at baseline, 12 weeks, and 24 weeks.

Results:

• All subjects lost a significant amount of weight

• Those on the control diet lost 6.4 ± 2.5% of their starting weight

• Those who were on the high-calcium diet lost a significantly greater amount of weight than the low-calcium diet group: 8.6 ± 1.1% of their starting weight

• Those on the high-dairy diet lost a significantly greater amount of weight than either the low-calcium diet and the high-calcium diet: 10.9 ± 1.6% of their starting weight

• Subjects on the high-calcium and high-dairy diets lost a significantly greater percentage of fat mass than those on the low-calcium diet:

• Those on the control diet lost 8.1 ± 2.3% of their body fat
• Those on the high-calcium diet lost 11.6 ± 2.2% of their body fat
• Those on the high-dairy diet lost 14.1 ± 2.4% of their body fat

 

Synopsis

Dietary calcium appears to help increase both weight loss and fat mass loss. Even in those who cannot consume dairy, taking a calcium supplement may help one to maintain weight loss or increase weight loss on a calorie-restricted diet.

Critique

While the results of this study are encouraging, several weaknesses in the study design should be noted.

First, the sample size is rather small - while 41 people were enrolled, only 32 participants completed the study, so there were about 10-12 people in each study group. Also, only obese adults were studied. There may not be an effect of calcium on weight or fat loss in subjects with healthy body weights. Finally, all the subjects followed a calorie-restricted diet, and the weight loss that occurred may have been due to the calorie restriction rather than the consumption of dairy products.

Others have criticized this study, arguing that the dairy products were not causing the weight loss observed in Zemel's study. In a similar study led by Jean Harvey-Berino, PhD, head of the nutrition and food sciences department at the University of Vermont, subjects who consumed 3 to 4 servings of dairy each day lost just as much weight as those following a high-dairy diet (3).

Finally, the lead author of the study, Michael Zemel, PhD, holds a patent on the claim that dairy products can increase weight loss.

Take-Home Tips

While the word is still out on whether dairy products promote weight loss, those who consume low amounts of calcium may see a benefit if they increase their calcium intake. Those who already consume an adequate amount of calcium (see below) may not experience a dramatic weight loss, but calcium remains an integral part of your diet.

•  Continue to include sources of calcium in your diet

•  Include a calcium supplement if you cannot consume dietary sources of calcium, or if you are at risk for osteoporosis

•  The RDA for calcium for both adult men and women is 1,000 mg/day; 1,200/day for those over 50

•  Do not exceed 2,500 mg of calcium per day

Dietary Sources of Calcium

•  Low-fat dairy

•  Fortified foods, such as orange juice

•  Calcium-processed tofu

•  Canned fish, such as salmon, with bones

•  Broccoli

•  Collard greens, turnip greens

•  Pinto beans, red beans

References

1. Zemel , MB , Shi, H, Greer, B, DiRienzo, D, Zemel, PC . (2000) Regulation of adiposity by dietary calcium FASEB J 14,1132-1138.

2. Pereira , MA , Jacobs, DR, Van, Horn L, Slattery, ML, Kartashov, AI, Ludwig, DS. (2002) Dairy consumption, obesity, and the insulin resistance syndrome in young adults: the CARDIA study JAMA 287,2081-2089.

3. Lesch Kelly, A. (2005). In a milky maze. Eating Well , 3: 17.