Cutting carbs better than cutting fat for type 2 diabetes patients

Lena Jonasson, professor of
cardiology, Linköpings University

DIABETES DIGEST – May 16, 2014 – For years people at risk for, or diagnosed with type 2 diabetes have been advised to consume a low-fat diet, but a growing body of evidence is showing that it might be better to reduce carbohydrates. The latest study comparing type 2 diabetes patients on a low-fat or low-carb diet showed that the low-carb diet significantly reduced inflammation, whereas the low-fat diet didn’t.

Inflammation may play an important role in type 2 diabetes, markers for inflammation in the blood are typically higher in people with type 2 diabetes compared to those without it. Inflammation is thought to play a role in increased blood vessel and heart disease and is linked to obesity and cancer.

The Swedish researchers led by Lena Jonasson, a cardiologist at Linköping University, Linköping Sweden, recruited 61 patients with type 2 diabetes and asked them to follow either a low-carb diet or a low-fat diet. A dietitian gave them menu suggestions and advice during three occasions of the first year of the two-year study. 

In addition, they restricted the energy provided by each diet to make them nearly equal for the energy derived from carbohydrate intake and fat intake. They took blood samples at the beginning of the study and after six months on the diet to look at blood markers for inflammation, blood sugar and other indicators of diabetes or heart disease. In addition they included 42 people without type 2 diabetes as a comparison group.

The results published in the Annals of Internal Medicine showed that both type 2 diabetes groups experienced similar weight loss, however those on the low-carb diet had significantly lower markers for inflammation and lower HbA1c than those on the low-fat diet. There was no change in the inflammation markers in the low-fat group.

Until 2007, the American Diabetic Association (ADA) recommended low-fat diets for weight loss and did not recommend low-carb diets. Citing growing evidence that low-carb diets could be as effective for weight loss, the organization modified its position to include both diets.

The authors concluded that their study suggests that restricting energy intake from carbohydrates to 20 percent may be effective for improving inflammation in people with type 2 diabetes.