Location: Obesity and Metabolism ResearchTitle: Dairy foods in a moderate energy restricted diet do not enhance central fat, weight & intra-abdominal adipose tissue loss or reduce adipocyte size & inflammatory markers in overweight & obese adults; Controlled feeding study) Author
|Van Loan, Marta|
Submitted to: Journal of Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/17/2011
Publication Date: 9/14/2011
Citation: Van Loan, M.D., Keim, N.L., Adams, S.H., Souza, E., Woodhouse, L.R., Thomas, A., Witbracht, M., Gertz, E.R., Piccolo, B., Brenner, A.R., Spurlock, M. 2011. Dairy foods in a moderate energy restricted diet do not enhance central fat, weight & intra-abdominal adipose tissue loss or reduce adipocyte size & inflammatory markers in overweight & obese adults; Controlled feeding study. Journal of Obesity. 10.1155/2011/989657. Interpretive Summary: Obesity is the number 1 public health problem today. Approaches used to reduce weight have included drug interventions, but specific dietary interventions have shown promising results. Inclusion of 3-4 servings of dairy foods into a moderate weight loss diet may result in increased weight and fat losses compared to diets without adequate dairy intake. We conducted a 15 week controlled feeding study and measured changes in body weight and fat, central fat, fat cell size, and markers of inflammation in healthy overweight and obese adults consuming either an adequate dairy-rich diet (AD: 3-4 servings of dairy/day) or a low dairy diet (LD: less than 1 serving/day). Both diet groups had a 500 calorie reduction in energy intake. Our results showed no increased weight or fat loss in the AD group compared to the LD group and no greater central fat loss or reduced fat cell size, or inflammation. Although the AD group did not have greater weight loss, weight loss was not inhibited by the inclusion of dairy foods into the weight loss diet. Also blood cholesterol levels were not adversely affected by the inclusion of dairy foods in the diet and vitamin D levels did improve with more servings of dairy foods. This study was conducted with healthy overweight and obese individuals and results may differ when dairy-rich foods are incorporated into the weight loss diets of overweight and obese individuals with health complications.
Technical Abstract: Background: Research on the role of dairy foods to enhance weight and fat loss when incorporated into a modest weight loss diet has had mixed results. Objective: A 15 week controlled feeding study to answer the question: do dairy foods enhance central fat and weight loss when incorporated in a modest energy restricted diet of overweight and obese adults? Design: A 3-wk run-in period to establish energy needs and a 12-wk, 500kcal/d energy reduced intervention with seventy-one low dairy consuming healthy overweight and obese women (n=51) and men (n=20) randomly assigned to diets with either = 1 serving of dairy/d (low dairy, LD) or 3-4 servings of dairy/d (adequate dairy, AD). All foods were weighed, prepared and provided by the metabolic kitchen. Body weight and fat, intra-abdominal adipose tissue (IAAT), resting metabolism, physical activity, fat cell size, subcutaneous adipose tissue (SAT) macrophage number, SAT metabolic and inflammatory gene expression, and circulating inflammatory markers were measured at run-in and 12-wk. Results: No significant differences were observed between groups in the amount of weight, fat, or IAAT lost or in SAT mRNA expression of inflammatory or metabolic markers. Circulating cytokines did not change. There was a significant increase (p = 0.02) in serum 25-hydroxyvitamin D in the AD group. No significant treatment effects were observed on fasting lipids, glucose, or insulin; however, insulin, leptin, PAI-1 and CRP decreased significantly with weight loss. Conclusion: We demonstrated that adequate servings of dairy foods incorporated into a weight loss diet does not hinder weight loss, improved vitamin D status and does not adversely affect serum lipids. Whether increased dairy intake during weight loss results in greater weight and fat loss for individuals with metabolic syndrome deserves further investigation, but attention to study duration, controlled or free-living environment, and sufficient sample size will be critical for the detection of significant changes due to treatment. Consideration should also be given to assessment of appetite, hunger and satiety with post-intervention follow up on weight regain.