Popular 'weight-loss' diets that are hyper-focused on carbohydrates, like the keto diet, may be doing more harm than good in the long run.
Sticking to a low-carb meal plan can help some with diabetes manage their weight and blood sugar levels, but a new study from Australia questions the long-term effectiveness and safety of this approach for those without diabetes.
If refined sugars and starches are not replaced with the 'right' foods, the 17-year-long analysis suggests a low-carb diet may actually increase the risk of type 2 diabetes.
"A healthy diet is a cornerstone for the prevention and management of type 2 diabetes," write researchers from Monash University and RMIT University, who led the study.
"However, the type of diet recommended for the prevention might vary from the diet recommended for the management of type 2 diabetes."
To investigate that possibility, the team of researchers combed through the health data of nearly 40,000 Melbourne residents, who were recruited between 1990 and 1994.
The cohort's socioeconomic, health, and nutritional information was collected at the start of the trial and again at a follow-up, sometime between 1995 and 1998 and between 2003 and 2007.
Each participant was given a low-carbohydrate score, which was not based on the absolute amount of carbs they reported regularly eating, but on the relative amount of carbs they ate compared to fats and proteins.
Those who scored in the top 20 percent got about 38 percent of their energy from carbohydrates.
Meanwhile, those who scored in the bottom 20 percent got about 55 percent of their energy from carbohydrates.
Ultimately, it was the former group, who cut out the most carbs, who were 20 percent more likely than those who cut out the least carbs to develop type 2 diabetes over the course of the study.
What's more, most of that risk was explained by a high BMI.
The findings suggest that a low-carb diet may result in weight gain in the long run, possibly increasing the risk of developing metabolic disease.
This may be "mainly due to the high fat content of the diet (specially unsaturated fat)," the researchers in Australia conclude.
Those who reported eating the fewest carbohydrates in the study tended to consume less fiber and eat more protein and fat than those who ate the most carbohydrates.
This suggests that solely focusing on carbohydrates isn't enough. "Other dietary items also need to be considered," the team argues.
Their study joins several others that have recently questioned the advisability of a keto diet, which promotes a low-carb, high-fat eating pattern.
For instance, an analysis published earlier this year found a worrying association between the keto diet and a higher risk of heart disease, stroke, type 2 diabetes, and irritable bowel syndrome.
Rigorous evidence suggests that a well-balanced diet is one of the best ways to prevent metabolic disease – and that means making sure a diet is, well, balanced.
Cutting out refined sugars and starches is all well and good, but if those carbohydrates are replaced with saturated fats, these new findings suggest it could be creating a whole other problem.
The study was published in Diabetes & Metabolic Syndrome: Clinical Research & Reviews.