Abstract
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. Objectives 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. Methods 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. Results 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;
Generated Summary
This randomized controlled trial investigated the impact of low-carbohydrate vegan diets on weight loss and metabolic measures in individuals with type 2 diabetes. The study compared the effectiveness of a low-carbohydrate vegan diet, high in canola oil and plant proteins, with a moderate-carbohydrate vegetarian diet. A total of 164 participants were randomly assigned to either diet for three months. The primary outcomes included changes in body weight, glycated hemoglobin, blood pressure, and potential greenhouse gas emissions. The research aimed to assess whether a low-carbohydrate vegan approach could offer a healthier and more sustainable alternative to traditional low-carbohydrate diets, particularly considering the environmental impact. The methodology involved detailed dietary assessments, regular monitoring of metabolic markers, and evaluation of greenhouse gas emissions associated with each diet. The study’s design incorporated rigorous control measures to ensure the reliability of the findings.
Key Findings & Statistics
- Weight Loss: Both the low-carbohydrate vegan and vegetarian diets led to similar reductions in body weight. The low-carbohydrate vegan diet resulted in an average weight loss of -5.9 kg (95% CI: -6.5, -5.28 kg), while the vegetarian diet resulted in -5.23 kg (95% CI: -5.84, -4.62 kg).
- Glycated Hemoglobin (HbA1c): Both diets also showed similar improvements in glycated hemoglobin levels, which is a measure of blood sugar control. The low-carbohydrate vegan diet decreased HbA1c by -0.99% (95% CI: -1.07, -0.9%), and the vegetarian diet decreased it by -0.88% (95% CI: -0.97, -0.8%).
- Systolic Blood Pressure: Systolic blood pressure was reduced in both diet groups. The low-carbohydrate vegan diet lowered systolic blood pressure by -4 mmHg (95% CI: -7, -2 mmHg), and the vegetarian diet reduced it by -6 mmHg (95% CI: -8, -3 mmHg).
- Greenhouse Gas Emissions: A significant difference was observed in potential greenhouse gas emissions. The low-carbohydrate vegan diet showed a reduction of -0.63 kgCO2/d (95% CI: -0.99, -0.27 kgCO2/d) compared to the vegetarian diet.
Other Important Findings
- Both the low-carbohydrate vegan and vegetarian diets reduced body weight.
- Both diets improved glycemic control, as indicated by reduced glycated hemoglobin levels.
- Both diets led to a decrease in blood pressure.
- The more plant-based diet (low-carbohydrate vegan) had a greater potential for reducing greenhouse gas emissions compared to the vegetarian diet.
Limitations Noted in the Document
- The study’s duration was limited to 3 months, which may not fully capture the long-term effects of the diets on weight loss and metabolic health.
- The study only included participants with type 2 diabetes, so the findings may not be generalizable to other populations.
- The reliance on 7-day food records for assessing dietary intake and estimating greenhouse gas emissions introduces potential inaccuracies due to the subjective nature of self-reporting.
- The study did not account for potential confounding factors such as physical activity levels, which could influence weight loss and metabolic outcomes.
- The study was limited to the comparison between two specific dietary interventions, and the findings may not apply to other types of low-carbohydrate or vegetarian diets.
Conclusion
In conclusion, the study highlights the beneficial effects of both low-carbohydrate vegan and vegetarian diets in managing type 2 diabetes, specifically in terms of weight loss, improved glycemic control, and reduced blood pressure. The key takeaway from this research is that a low-carbohydrate vegan diet, which is heavily plant-based, can be a potentially healthier option than standard high animal fat and protein diets. The data suggests that both diets led to comparable positive metabolic outcomes, it’s important to note the impact of the low-carbohydrate vegan diet in reducing greenhouse gas emissions. This environmental advantage supports the promotion of more sustainable dietary approaches. The study’s findings support that a shift towards more plant-based diets could offer a dual benefit: improved metabolic health and reduced environmental impact. The study’s findings provide a foundation for further exploration and research. Future studies should focus on long-term effects, expanding the scope beyond diabetes, and refining dietary guidelines to enhance both health and environmental sustainability. The results of this trial provide important information for individuals with diabetes considering dietary interventions. The comparative effectiveness of the two dietary approaches highlights the viability of plant-based options in the clinical management of diabetes, the study underscores the importance of considering both health and environmental sustainability when making dietary recommendations.