In the past, some doctors and health professionals believed by following a low-fat diet and replacing fatty foods with carbohydrates that people may be at an increased risk of diabetes, or changes that could lead to the disease.
To investigate, researchers studied more than 2000 postmenopausal women. About 900 of the women, selected randomly, were told to decrease their total fat intake so that fat accounted for about 20 percent of the calories in their diet. As part of the new diet, women were also told to increase the number of fruit, vegetable, and grain servings they ate.
The other 1,400 women, serving as a comparison group, were not given any extra nutritional guidance or told to change their diet.
The researchers followed the women for the next 6 years with surveys on diet and exercise and also tested their blood for sugar and insulin levels to look for diabetes or its warning signs.
Women in the low-fat group, on average, ended up getting between 25 and 29 percent of their calories from fat in follow-up surveys. That compared to 36 to 37 percent in the group without a diet intervention. The diet group also generally ate fewer total calories and more fruits, vegetables, grains, and sugar than the comparison group, on average.
The Institute of Medicine recommends that adults get 20 to 35 percent of their calories from fat.
After 1 year, women on the low-fat diet had lost more weight than the comparison group and had bigger decreases in their blood sugar and insulin levels.
By 6 years, the groups looked similar on those measures, indicating to researchers that the lower-fat, higher-carbohydrate diet hadn't increased women's chances of getting diabetes.
However, in women who already had diabetes at the start of the study, those on the low-fat diet had a larger increase in blood sugar levels in the first year compared to women who didn't change their diet.
The study, published in the American Journal of Clinical Nutrition, suggests that following a well-balanced low fat diet that is rich in healthy carbohydrates, such as whole grains, fresh fruits and vegetables can assist with short term weight loss, and lower the risk of diabetes.
Currently, Canada's Food Guide recommends Canadians get between 7 and 10 servings of fruit and vegetables, and 6 to 8 servings of grain products each day. For more information on Canada's Food Guide, click here.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.