by Lindsay Orbeta, MS, RD
Preventive Medicine
Saturated fats from dairy products may not be detrimental for cholesterol and waistlines, after all. Recent research suggests whole-fat dairy is linked to significant reductions in body fat. However, current dietary recommendations still stand (by many experts and the public) that saturated fat raises cholesterol levels and therefore the risk of heart disease. Here’s new evidence that’s counterintuitive: A meta-analysis revealed a trend where high-fat dairy lowered the risk of obesity.1 A corresponding study found middle-aged men who consumed high-fat milk, butter and cream were significantly less likely to become obese over 12 years, compared with men who never or rarely ate high-fat dairy.2 While the mechanisms are unclear, a simple explanation is that high-fat foods are more satiating. Fats are slow to empty from the stomach, delay digestion, and in short- curb appetite so we end up eating less overall.
Or possibly, probiotics (friendly bacteria) found in yogurt may alter the microbes living in our stomach, and impact hunger signals. A study lasting half a year monitored obese but otherwise healthy adults.3 For the first three months, they followed a supervised, low-calorie diet. For the next three months, they received a personalized diet plan but no longer restricted caloric intake. The entire time, half of subjects took two probiotic pills/day- roughly the same amount of bacteria you’d get in two servings of yogurt. The other half of subjects received a placebo.
After six months, women taking the placebo maintained their weight loss, but women taking probiotics kept on losing weight, nearly twice as much, for a total average loss of 11.5 pounds. More intriguing, women taking probiotics lost a greater percentage of fat mass and had significant drop in blood levels of leptin, a hormone that helps control appetite. The probiotics significantly reduced the amount a type of bacteria in these ladies’ bellies (or, gut ‘microbiome’) that has been linked with obesity. A recent body of studies have shown lean people have a greater diversity and number of gut bacteria compared to obese people. While probiotics may positively affect health, it remains to be seen which strains might be helpful and why.
Reference:
1. Kratz, M et al. Eur J Nutr. 2013 Feb;52(1):1-24. The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease.
2. Holmberg, S. et al. Scand J Prim Health Care. 2013 Jun;31(2):89-94. High dairy fat intake related to less central obesity: a male cohort study with 12 years’ follow-up.
3. Sanchez, M. et al. Br J Nutr. 2013 Dec 3:1-13. Effect of Lactobacillus rhamnosus CGMCC1.3724 supplementation on weight loss and maintenance in obese men and women
About the Author:
Lindsay is a Registered Dietitian with a double Master of Science degree in Sports Nutrition and Exercise Physiology, and Ironman triathlon finisher. Currently Lindsay works as a public health nutritionist in Oakland and was formerly the Nutritionist for the Sports Club LA in San Francisco. A professional speaker for the last seven years, Lindsay has given nutrition seminars for corporate employee wellness programs, managed by BaySport, with Visa, Inc., and the Federal Reserve Bank.
