As you can see by the title, I'm giving you (and me) a break from the artificial sweetener studies. Dairy gets a bad rap by a lot of news outlets. One of the common accusations against dairy is that it will make you fat or if you are dieting, it will keep you from losing weight. Are these accusations true? Let's find out. In this article, I am going to take a few scientific studies, review them, and summarize each of them in plain English. At the end, I will give you my final thoughts on the subject.
Study: Effects of Calcium and Dairy on Body Composition and Weight Loss in African-American Adults [1]
Phase I:
The first phase on this experiment looked at weight maintenance. Thirty-four obese subjects were maintained on either a high diary (3 servings/day) high calcium (1200 mg/d) or low dairy (0-1 servings/day) low calcium (500 mg/d) diet for 24 weeks. (For reference, the RDI for calcium is 1000 mg/d for adults age 19-70. [2]) Body weight and waist circumference were measured weekly. Body fat, blood pressure, circulating insulin, glucose, lipids, total cholesterol, and HDL cholesterol (the "good cholesterol") were measured at the beginning of the study and at weeks 12 and 24.
Results:
Unsurprisingly, there was no weight loss in either group since it was a weight maintenance diet. Surprisingly, while the high dairy group did not lose any weight, they did significantly decrease body fat and waist circumference and increase lean body mass.
The high dairy group also experienced significant decreases in blood pressure and circulating insulin levels, while the low dairy group did not experience these changes. There was no significant effect on circulating lipids in either group.
PHASE II:
The second phase followed a similar protocol to phase one, except it studied 29 subjects and they were put in a Calorie Deficit of 500 Calories/day below what they required to maintain their weight.
RESULTS:
The diet produced weight and fat loss in both groups; however, the high dairy group lost nearly double the weight and triple the fat as the low dairy group. In addition, the low dairy group lost 13 times more lean body mass than the high dairy group.
Circulating insulin decreased by twice as much in the high dairy group. There was no significant change in blood pressure for either dieting group, but it is important to note that unlike the maintenance groups, there were 4 subjects in the high dairy and 3 subjects in the low dairy who were on anti-hypertensive medication throughout the experiment which may have skewed the results.
Study: Effect of Energy-Reduced Diets High in Dairy Products and Fiber on Weight Loss in Obese Adults [3]
Seventy-two men and women between the ages of 25 and 70 with a BMI of 30-40 took part in a one-year study. The phase of the experiment that is relevant to this conversation compared two 500 Calorie/day deficit diets. One group was consuming 800mg of calcium and two servings of dairy per day. The other was consuming 1400 mg of calcium and four servings of diary per day.
RESULTS:
Both groups lost a significant amount of fat. The moderate diary group lost 16.53 pounds and the high dairy group lost 19.84 pounds. There were no significant differences in other various health markers between the two groups. The difference isn't quite as big as the previous study but I don't know anyone who wouldn't want an extra 3 pounds of fat loss in their diet. We must also keep in mind that this study compared a moderate dairy diet with a high dairy diet while the first compared a low dairy diet and high dairy diet.
Study: Calcium and Dairy Acceleration of Weight and Fat Loss during Energy Restriction in Obese Adults [4]
This study took 41 obese, but otherwise healthy adults, and randomized them into one of three groups. The first group had 0-1 servings of dairy per day and 400-500 mg calcium/day. The second group had the same diet but added a calcium supplement to total 1200-1300 mg calcium/day. The third group had 3 servings of dairy/day and 1200-1300 mg calcium/day. All three diets had a 500 Calorie/day deficit. Body weight and waist circumference was measured weekly. Body fat was measured at the beginning of the study and at weeks 12 and 24. Fasting levels of circulating insulin, glucose, triglycerides, total cholesterol, and HDL cholesterol were also measured at the beginning, week 12, and week 24..
Results:
The results of this study unsurprisingly showed fat loss for all three groups; however, the high calcium group lost 1.76 more pounds of fat than the low calcium group. The high dairy group lost 5.18 pounds more than the low calcium group.
The high dairy group decreased their waist circumference by ~9cm. The high calcium group decreased their waist circumference by ~7cm. The low calcium group decreased their waist circumference by ~4.5cm. The high dairy group showed more improvements in glucose tolerance and blood pressure in comparison with the other groups.
Final Thoughts
I went into this article already knowing that diary had body-composition benefits, but I must admit, I honestly did not realize that it benefited us to this extent. Dairy even showed reduction in body fat and an increase in muscle mass without changing the total amount of protein in the diet or adding exercise, in the first study. I believe the science is clear. Despite what some documentaries (that shall remain nameless) claim, dairy has profound health and body composition benefits.
Thanks for reading! Next week we will be discussing the effects of dairy on athletic performance. God bless you AND your family and I'll see you then!
References:
[1] Zemel, M. B., Richards, J., Milstead, A., Campbell, P. (2005) Effects of Calcium and Dairy on Body Composition and Weight Loss in African-American Adults. Obesity, 13(7), 1218-1225, 10.1038/oby.2005.144
[2] https://www.nrv.gov.au/nutrients/calcium
[3] Thompson, W. G., Holdman, N. R., Janzow, D. J., ... Zemel, M. B. (2005) Effect of Energy-Reduced Diets High in Dairy Products and Fiber on Weight Loss in Obese Adults. Obesity, 13(8), 1344-1353, 10.1038/oby.2005.163
[4] Zemel, M. B., Thompson, W., Milstead, A., ... Campbell, P. (2004) Calcium and Dairy Acceleration of Weight and Fat Loss during Energy Restriction in Obese Adults. Obesity, 12(4), 582-590, 10.1038/oby.2004.67
