A researcher from the University of Canberra has found that low glycaemic index (GI) diets are not effective as an intervention for overweight and obesity for people with diabetes in a new paper published in Obesity Reviews.
The study, conducted by Adjunct Professional Associate Dr Kerry Mills, from the Centre for Research in Therapeutic Solutions, investigated whether low GI diets reduce body weight or markers of blood glucose in children, adolescents or adults with overweight or obesity.
The theory behind a low GI diet is that if a person eats low GI foods, for example lentils, they feel fuller for longer, do not get hungry as quickly, and therefore do not eat as much.
“To test the hypothesis, we conducted a systematic review and meta-analysis of randomised controlled trials comparing low GI diets with other diet types,” said Dr Mills.
The analysis included 101 studies involving over 8,500 participants and looked at groups within the overall cohort such as the type of control diet, blood glucose control, baseline body mass index (BMI) and dietary GI.
The study found that a low GI diet had limited effect, except in people with normal blood glucose levels, in whom moderate weight loss was recorded.
“Low GI diets, especially those achieving a substantial decrease in GI, were moderately effective in lowering body weight. This suggests, however, that in these studies the participants strictly followed the diet,” continued Dr Mills.
The study showed that low GI diets had no effect on weight loss in those participants who had a compromised insulin system or impaired glucose tolerance, or type 2 diabetes. This surprising result may be a consequence of the fact that people with impaired insulin sensitivity continue to feel hungry even when their blood insulin levels are high – a situation that would normally lead to a feeling of satiety.
“It is clear from the study that a low GI diet is not effective in the case of obesity or overweight where type 2 diabetes is present, drawing the conclusion that it is not an effective solution for weight loss in these patients,” Dr Mills said.
Dr Mills cautioned that doctors should consider the presence of diabetes when recommending weight loss programs, and that dietary change should not take place without professional advice.
“At the end of the day, people with overweight or obesity should seek assistance from a registered dietician or general practitioner to ensure healthy weight loss,” concluded Dr Mills.
