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How Exercise Can Permanently Alter the Behavior of Fat

Fitday Editor

Two recent studies, one performed on mice and the other on humans, found that regular exercise can train dangerous fat into more metabolically beneficial good fat.

How Fat Works

Fat is a biologically active tissue within the body that not only stores energy but also produces hormones and other substances which can alter the health of an individual. Fat can develop almost anywhere in the body but usually accumulates in the following areas: subcutaneously, just under the skin, where it also acts as a shock absorber and an insulator; viscerally, more deeply, around vital organs; and where genetically determined such as in the breasts or hips.

Harvard Health reports that excess body fat, especially abdominal visceral fat, secretes harmful immune system chemicals that can raise the risk of cardiovascular disease by increasing insulin resistance and chronic inflammation and effecting cell sensitivity to insulin, blood pressure, and blood clotting. Other conditions associated with higher abdominal fat, even if overall weight is normal, are cancer, diabetes, risk of premature death, worsening memory, and less verbal fluency.

The Two Types of Fat

The two main types of fat in the body are brown and white fat, both responsible for very different things in the body. White fat stores energy and nutrients in large fat droplets, whereas brown fat is composed of smaller droplets used to burn to generate body heat.

Small mammals like rodents retain brown fat throughout their lives. Humans only have rich stores as infants. Babies lack the ability to produce body heat by shivering so brown fat is burned to maintain body temperature. It was thought that brown fat disappeared in adulthood, but emerging evidence shows that we may retain a small amount which appears to be more active in colder months. Scientists have also found that lean individuals tend to have more brown fat than those who are overweight or obese.

Exercise Makes White Fat Act Brown

In the two studies funded by the American Diabetes Association and the National Institutes of Health, researchers found that after regular exercise, in both animal and human studies, unhealthy white fat acted more like the beneficial brown fat. According to the Joslin Diabetes Center, the "trained" white fat had thousands of newly activated genes specializing in revving up the metabolism. These benefits were also observed when transplanted into a sedentary animal.

With these new discoveries, there grows a greater motivation to perform more physical activity. And, researchers say, regardless of weight-loss results, exercise will still train the white fat to be more metabolically active.

Fat Transplants?

Results from this study could also mean that fat transplantation or fat changing pills could be used as treatments for overweight and obesity in the near future. Laurie Goodyear, PhD, emphasizes however, "Exercise training affects so many tissues throughout the body, to make one pill that's going to mimic all the effects of exercise I think is very difficult to do..."

Besides controlling weight and reducing the risk of cardiovascular disease, exercise also reduces the risk for type 2 diabetes, metabolic syndrome, and some cancers. It also strengthens bones and muscles, improves mental health and mood, and increases the chances of living longer.

Mandy Seay is a bilingual registered and licensed dietitian who holds both a bachelor's degree in nutrition and in journalism. After gaining 30 pounds while living abroad, Mandy worked to lose the weight and regain her health. It was here that she discovered her passion for nutrition and went on to pursue a career as a dietitian. Mandy currently works as a nutrition consultant and freelance writer in Austin, Texas, where she specializes in diabetes, weight management and general and preventive nutrition. She recently published her first book, Your Best Health, a personalized program to losing weight and gaining a healthy lifestyle. Please visit Mandy's website at

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