Exercise and Visceral Fat Reduction

DECEMBER, 2007 - It is often thought that exercise reduces abdominal fat and/or visceral fat in a way that is independent of weight loss. But does the latest scientific evidence support this?
Exercise and Visceral Fat Reduction

Early Studies
It has only been recognized in the past decade or so that the visceral component of abdominal fat imparts the most serious health effects. A 1999 review looked at the available studies. The number of trials was small and the study designs flawed, but the authors did find a trend that exercise without weight loss did not reduce waist circumference while exercise-induced weight loss did lead to a small decrease in waist circumference. However, waist circumference is an indirect measure of abdominal fat and does not give any information about how much fat is visceral and how much is subcutaneous. The authors summarized by saying that better-quality studies that looked specifically at the impact of exercise on the components of abdominal fat were needed before any conclusions could be made.1

Newer Findings
In 2006, another review was published. This review included studies that addressed some of the limitations found in 1999. While the results were mixed, 70 percent of the studies reviewed showed significant losses of abdominal fat when compared with controls. The researchers concluded that, by using new technologies that can quantify fat stores, there is limited evidence that exercise can lead to a loss of visceral and total abdominal fat without a change in weight or waist circumference. However, the authors also pointed out that none of the studies they reviewed met the criteria of a "gold standard" randomized clinical trial and stressed that such trials need to be conducted.

The Latest Findings
The results of one "gold standard" trial were published in March 2007. The goal of the six-month study was to compare the effect on body composition and fat distribution between groups assigned to follow a control diet, a diet that reduced caloric intake by 25 percent or a diet plus exercise group. Using sophisticated measuring techniques, the researchers found no differences between the diet and diet plus exercise groups in weight lost, total fat lost or visceral fat lost.2

State of the Science in 2008
Based on the latest research, it appears that no definitive conclusions can be drawn as to whether or not exercise has an independent ability to reduce visceral fat stores. As soon as a few more studies are published, the answer should be clearer. What is already clear, however, is that weight loss reduces visceral fat.

The Weight Watchers Approach:
By using a comprehensive approach that includes food and activity plans, the reduction of visceral fat and the health improvements that have been shown to accompany reduced abdominal fat are maximized.






FOOTNOTES

1 Ross R, Janssen I. Is abdominal fat preferentially reduced in response to exercise-induced weight loss? Med Sci Sports Exerc. 1999 Nov;31(11 Suppl):S568-72.

2 Kay SJ, Fiatarone Singh MA. The influence of physical activity on abdominal fat: a systematic review of the literature. Obes Rev. 2006 May;7(2):183-200.

3 Redman LM, Heilbronn LK, Martin CK, Alfonso A, Smith SR, Ravussin E; Pennington CALERIE Team. Effect of calorie restriction with or without exercise on body composition and fat distribution. J Clin Endocrinol Metab. 2007 Mar;92(3):865-72.