Weight Loss Improves Insulin Response, Reduces Stress

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Exercise and diet induced weight loss improved measures of oxidative stress and insulin sensitivity in adults with characteristics of the metabolic syndrome, by R.S. Rector and colleagues. Am J Physiol Endocrinol Metab 293:E500-E506, 2007

What is the problem and what is known about it so far?

Cardiovascular disease (CVD, disease of the heart and blood vessels) is more likely in people with metabolic syndrome, a cluster of symptoms that include a large waist size, high blood pressure, insulin resistance (the body’s inability to respond to and use the insulin it produces), and high levels of fats in the blood.

Obesity and insulin resistance are linked to CVD, but scientists suspect that other factors may also be at work. One possible factor is oxidative stress, a biological process that allows toxic products to build up in the body. Oxidative stress is involved in the development of atherosclerosis. Atherosclerosis is when deposits of plaque build up inside the arteries, causing them to clog and harden, and is a sign of CVD.

Why did the researchers do this particular study?

The researchers wanted to evaluate the effects of weight loss caused by diet and exercise on oxidative stress and insulin among people with metabolic syndrome.

Who was studied?

The study included 21 women and 9 men, 18 to 50 years old, who were overweight or obese but had stable weight.

How was the study done?

The men and women had a physical exam and had blood drawn for lab tests. Over an average of 6 months, the men and women followed a strict meal plan and took part in a supervised exercise program. At the end of the study period, blood was drawn again for lab tests.

What did the researchers find?

Participants who lost 10% or more of their weight showed significant improvements in the body’s ability to handle insulin. They also showed improvement in signs of oxidative stress.

What were the limitations of the study?

There could be other factors related to CVD that were not measured by the research. Also, the number of people participating in the study is rather small.

What are the implications of the study?

Weight loss caused by diet and exercise can help the body handle insulin and lower oxidative stress. More research may show whether the chance of CVD is also lowered.