Best low-carb diet for diabetes: Animal versus plant-based protein
Of the 37 million adults in the US who have diabetes, around 95% have type 2 diabetes. Type 2 diabetes develops when the body stops responding to insulin, the hormone that regulates blood glucose levels. People with type 1 diabetes do not produce insulin – this is thought to be caused by an autoimmune reaction. (See also our article on Diabetes)
In a October 2022 article, Robby Berman suggests that a diet low in carbohydrates could increase type 2 diabetes risk – however, the study did not differentiate whether this was due to carbohydrate reduction or just calorie reduction (1).
In another research study, also from October 2022, Yeli Wang, et al, suggest that the factor which affects the risk of type two diabetes is in fact the type of non-carbohydrate food that a person eats.
Long term diet research
The study was a prospective cohort study on 203,541 adults in the US over more than 30 years. At the beginning of the study, none of the participants had been diagnosed with type 2 diabetes, cardiovascular disease, or cancer.
Every four years, the participants undertook dietary assessments via the use of a validated food frequency questionnaire. The researchers then created scores based on the percentage of energy each person got from their daily intake of protein, fats, and carbohydrates. The participants were then divided into five groups – the low-carbohydrate group got around 40% of their daily calories from carbohydrates.
The quality of diet was then evaluated by classifying 18 groups of nutrients such as whole grains, fruits, vegetables, nuts, legumes, sweets and desserts, animal fat, dairy, and meat.
The results showed that overall a low carbohydrate diet did not reduce the risk of type 2 diabetes, but a considerable difference was found when sources of dietary protein were considered separately.
Vegetable protein reduces risk
Individuals who mostly had vegetable protein in their diet had a 6% reduced risk of type 2 diabetes over 30 years, and for those who reduced their intake of refined carbohydrates, the risk was reduced further at 15% less than those on a regular diet. In contrast, those on a low-carbohydrate diet who ate mainly animal protein had a 35% higher risk of type 2 diabetes, increasing to 39% in those whose diet was also low in whole grains.
Limitations to the study include the lack of specificity when it came to protein sources consumed and what other lifestyle factors were taken into account. Another limitation is that the cohort was primarily white. The risk of type 2 diabetes is higher in certain other ethnic groups – for example, in the US, type 2 diabetes is almost twice as common in African Americans as it is in non-Hispanic whites.
References
1. Berman, R. Low carb diet may reduce type 2 diabetes risk, promote weight loss. Medical News Today, 31 October, 2022.
2. Wang Y, Hu Y, Wan Y, Rimm EB, Hu FB, Sun Q. Low-Carbohydrate Diets and Risk of Type 2 Diabetes in U.S. Men and Women. Circulation 2022;146:A13226, 30 October, 2022.