Issue 153 Item 5 Energy Bars Not Your Best Option for Weight Loss

Low- or moderate- carbohydrate energy bars don’t reduce insulin levels in the blood as much as was thought. Low- or moderate-carbohydrate foods create less of an insulin spike in the blood after eating, which can help people to burn fat and lose weight, according to advocates of diet plans such as the Atkins and Zone diets. However, a study found that low- or moderate- carbohydrate energy bars don’t reduce insulin levels in the blood as much as was thought.

This means that these energy bars may not promote weight loss as they are advertised to do. Although manufacturers add protein and fat to the bars, overall the energy content is similar to a higher carbohydrate energy bar.

The study involved 20 adults who ate one of five test meals on five separate days: a low-carbohydrate energy bar (Atkins Advantage Bar); a moderate-carbohydrate energy bar (Balance Bar); a high-carbohydrate energy bar (Power Bar); white bread, which is nearly all carbohydrate; and broiled, boneless chicken breast, which contains no carbohydrate.

The moderate-carbohydrate Balance Bar supports the Zone diet, which recommends a diet of 40 percent carbohydrates, 30 percent fat and 30 percent protein. The low-carbohydrate Atkins Advantage bar supports the Atkins diet.

Researchers took blood samples to measure participants’ blood glucose and insulin levels at various times during the study. The insulin response from eating white bread, which researchers were familiar with, was used to compare the insulin responses of the other meals.

The low-carbohydrate bar lowered insulin by about one-quarter compared to eating white bread. After eating the moderate-carbohydrate energy bar, insulin levels rose by more than one-third, and increased close to three-quarters after eating the high-carbohydrate energy bar. The chicken meal resulted in insulin levels that were more than three-quarters lower than those caused by eating white bread.

Researchers were surprised that the moderate-carbohydrate bar resulted in a high insulin response. They say that a combination of factors, such as carbohydrate and protein, may work together to raise insulin levels.

High insulin levels impair the body’s ability to burn fat, making it harder to lose weight. Some diet companies advertise that their lower carbohydrate products will keep insulin levels low, however there is no evidence to support such claims, according to researchers. Medical Science Monitor January 2003;9(2):CR84-90