A new 17-year study has found that low-carbohydrate, high-fat diets for weight loss may increase the risk of developing type 2 diabetes by 20%, challenging the effectiveness of such diets in diabetes prevention. The research, conducted by Monash University and RMIT University and led by Distinguished Professor Barbora de Courten OAM and PhD student Robel Kabthymer, was published in Diabetes and Metabolic Syndrome.
The study analyzed data from nearly 40,000 Melbourne residents, aged 40-69, who were part of the Melbourne Collaborative Cohort Study (MCCS) from 1990 to 1994. Their health outcomes were reviewed in subsequent years, allowing researchers to assess the impact of carbohydrate intake on diabetes risk.
Researchers calculated a Low Carbohydrate Score (LCD) based on the percentage of energy derived from carbohydrates, fats, and proteins. They found that individuals with a diet consisting of 38% carbohydrates faced a 20% higher risk of developing type 2 diabetes compared to those with a diet containing 55% carbohydrates. This increased risk is thought to be linked to higher rates of obesity associated with low-carb diets.
Professor de Courten noted that this is the first Australian study to explore the long-term effects of low-carbohydrate diets on chronic diseases. She emphasized that while high-carbohydrate diets high in processed sugars can contribute to weight gain and insulin resistance, the study suggests that low-carbohydrate diets might elevate diabetes risk through obesity, potentially due to higher fat intake and lower fiber consumption.
The study underscores the importance of focusing not just on carbohydrate quantity but also on the quality of carbohydrates, proteins, and fats consumed. A balanced diet, similar to the Mediterranean diet—which emphasizes minimally processed carbohydrates, fiber-rich foods, healthy fats, and sufficient protein from diverse sources—may be more effective in preventing type 2 diabetes.