It’s becoming common practice for people with type 2 diabetes to be recommended a low carbohydrate (low carb) dietary approach to help manage their condition.
In fact, there’s now substantial evidence to show how effective this approach is for controlling blood glucose levels and, in many cases, even sending type 2 diabetes into remission.
But the question researchers are now trying to solve is whether a low carb diet is as effective in preventing type 2 diabetes as it has been for treating those who already have the condition.
While there’s a lot of evidence highlighting the health benefits of low carb diets for those with type 2 diabetes, there are fewer studies regarding the efficacy of low carb diets in those with pre-diabetes.
According to new research from Tulane University, a low carb diet may be effective for those at risk of type 2 diabetes by helping to lower blood sugar levels before they reach type 2 diabetes levels.
Pre-diabetes: A massive problem
Approximately two million Australians have pre-diabetes, many undiagnosed. Those with pre-diabetes are at increased risk for developing type 2 diabetes, heart attack and stroke.
Being diagnosed with pre-diabetes doesn’t mean that you will develop type 2 diabetes, but it does mean you’re 10-20x times more at risk of developing the condition than those with normal blood glucose levels.
One of the biggest challenges is that pre-diabetes often has no signs or symptoms, so we reckon the more you know about pre-diabetes, the better equipped you are to take care of your health and reduce your risk of developing type 2 diabetes.
Low carb vs. your usual diet
The Tulane University randomised control trial involved participants aged 40 - 70 years old, with an unmedicated HbA1c of 6.0% to 6.9% (42-52 mmol/mol).
Researchers randomly split the one hundred fifty participants into two groups, with one group assigned to a low carb diet and the other group continuing with their usual diet.
The low carb group had a target of <40 net grams of carbs in the first three months and <60 grams for months three to six, and they received dietary counselling.
The low carb diet group had 50 per cent of their calories coming from fats, predominantly healthy fats found in foods like olive oil and nuts.
After six months, the low carb diet group had a “modest but clinically relevant” drop in HbA1c compared to the group who stayed on their usual diet.
In addition, the low carb group experienced other benefits over their counterparts, including weight loss and lowered fasting glucose levels.
There is strong international evidence that suggests type 2 diabetes can be prevented in up to 58% of cases in the high-risk (pre-diabetes) population by eating well and exercising.
And the evidence is growing, with this particular study showing promising results for using a low carb diet to lower HbA1c and prevent type 2 diabetes.
The lead researcher said that while this study doesn't prove that a low carb diet prevents diabetes, it opens the door to further research about mitigating health risks of pre-diabetes and diabetes not treated by medication.
“The key message is that a low-carbohydrate diet, if maintained, might be a useful approach for preventing and treating type 2 diabetes, though more research is needed,” said lead author Kirsten Dorans, assistant professor of epidemiology at Tulane University School of Public Health and Tropical Medicine.
Dorans KS, Bazzano LA, Qi L, He H, Chen J, Appel LJ, Chen CS, Hsieh MH, Hu FB, Mills KT, Nguyen BT, O'Brien MJ, Samet JM, Uwaifo GI, He J. Effects of a Low-Carbohydrate Dietary Intervention on Hemoglobin A1c: A Randomized Clinical Trial. JAMA Netw Open. 2022 Oct 3;5(10):e2238645. doi: 10.1001/jamanetworkopen.2022.38645. PMID: 36287562.
Colberg, Sheri R et al. “Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement.” Diabetes care vol. 33,12 (2010): e147-67. doi:10.2337/dc10-9990
Jaana Lindström, Anne Louheranta, Marjo Mannelin, Merja Rastas, Virpi Salminen, Johan Eriksson, Matti Uusitupa, Jaakko Tuomilehto, for the Finnish Diabetes Prevention Study Group; The Finnish Diabetes Prevention Study (DPS): Lifestyle intervention and 3-year results on diet and physical activity. Diabetes Care 1 December 2003; 26 (12): 3230–3236. https://doi.org/10.2337/diacare.26.12.3230