Following a low-carbohydrate vegan diet led to greater improvement in several health measures compared to a standard vegetarian diet in people with type 2 diabetes — although both diets were beneficial, according to a new study published in the American Journal of Clinical Nutrition.
A vegan diet is completely free of animal products — that means no meat, poultry, fish, dairy, or eggs. Many low-nutrition foods happen to be vegan, though — potato chips are an example — so following a vegan diet for health generally means sticking to some additional guidelines, such as consuming minimally processed foods and an abundance of fruits and vegetables. Studies have shown that plant-based diets — which are not necessarily vegan, but which include a wide array of healthy plant foods — may offer numerous health benefits, including a lower risk of developing type 2 diabetes and a lower risk for dementia. Getting your dietary fat from plants, rather than animal products, is linked to a lower risk for stroke, and a healthy plant-based diet may even improve outcomes related to COVID-19. That doesn’t mean all animal products are bad for you, though. There is evidence that fermented dairy products, in particular — such as yogurt, kefir, and cultured buttermilk — are beneficial to your health, including cardiovascular health.
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For the latest study, researchers randomly assigned 164 participants with type 2 diabetes to follow either a low-carb vegan diet or a vegetarian diet for three months. The low-carb vegan diet was high in canola oil and plant-based protein, while the vegetarian diet was designed to be a healthy “therapeutic” diet. Both diets were recommended to participants in a way that would cover 60% of the calories they would need to maintain their body weight — in other words, the diets were intended to lead to weight loss.
All participants had type 2 diabetes for at least six months and were not taking insulin, as noted in an article on the study at Healio. They were all taking a stable dose of blood-glucose-lowering drugs for at least a month before the study, and had an A1C value (a measure of long-term blood glucose control) between 6.5% and 8.5% — indicating good to less-than-optimal blood glucose control.
Improvements linked to both styles of plant-based eating
At the end of the three months, 70 out of 83 participants (84%) had stuck to following the low-carb vegan diet, while 68 out of 81 participants (84%) had stuck to following the vegetarian diet. Among participants who stuck to their assigned diet, those in the low-carb vegan group lost an average of 5.9 kilograms (13.0 pounds), while those in the vegetarian group lost an average of 5.2 kilograms (11.5 pounds). Members of the low-carb vegan group saw their average A1C level drop by 0.99%, while for members of the vegetarian group it dropped by 0.88% — a striking decline in A1C for both groups. When it came to systolic blood pressure (the “top number”), members of the low-carb vegan group saw a drop of 4 mmHg, while members of the vegetarian group saw a drop of 6 mmHg on average.
For all of these health measures, none of the differences between the two diet groups were statistically significant, meaning they could have been due to chance — but the overall improvements in both groups were both statistically significant and large enough to potentially make a meaningful difference in health. One area where there was a significant difference between the two groups, though, was in the estimated greenhouse gas emissions linked to their diet — the low-carb vegan group was linked to lower emissions by 0.63 kilograms of carbon dioxide each day per person, on average.
The researchers concluded that following a calorie-restricted low-carb vegan or vegetarian diet could lead to meaningful improvements in health measures in people with type 2 diabetes, and that a low-carb vegan diet is the better choice when it comes to environmental impact.
Want to learn more about plant-based eating? Read “Vegetarian and Vegan Type 1 Diabetes” and “Myths About the Vegetarian Diet.”