Low-carbohydrate, high animal fat and protein diets have been promoted for weight loss and diabetes treatment. We therefore tested the effect of a low-carbohydrate vegan diet in diabetes as a potentially healthier and more ecologically sustainable low-carbohydrate option.
We sought to compare the effectiveness of a low-carbohydrate vegan diet with a moderate-carbohydrate vegetarian diet on weight loss and metabolic measures in diabetes.
One hundred and sixty-four male and female participants with type 2 diabetes were randomly assigned to advice on either a low-carbohydrate vegan diet, high in canola oil and plant proteins, or a vegetarian therapeutic diet, for 3 mo, with both diets recommended at 60% of calorie requirements. Body weight, fasting blood, blood pressure, and 7-d food records, to estimate potential greenhouse gas emissions, were obtained throughout the study with tests of cholesterol absorption undertaken at baseline and end of study on 50 participants.
Both low-carbohydrate vegan and vegetarian diets similarly but markedly reduced body weight (−5.9 kg; 95% CI: −6.5, −5.28 kg; and −5.23 kg; 95% CI: −5.84, −4.62 kg), glycated hemoglobin (−0.99%; 95% CI: −1.07, −0.9%; and −0.88%; 95% CI: −0.97, −0.8%), systolic blood pressure (−4 mmHg; 95% CI: −7, −2 mmHg; and −6 mmHg; 95% CI: −8, −3 mmHg), and potential greenhouse gas emissions, but only for potential greenhouse gas emissions was there a significant treatment difference of −0.63 kgCO2/d (95% CI: −0.99, −0.27 kgCO2/d) favoring the low-carbohydrate vegan diet.