Eligible Participants

•  Healthy adults, 18 years of age or older
• One of twins that will both be participating
• Willing to consume a plant-based diet (vegetables, fruit, whole grains, legumes, etc.)
• Willing to consume meat/eggs (beef, pork, chicken, eggs) at least once a day
• Willing to consume dairy (milk, yogurt, cheese) at least once a day

Study Design

Twenty-two identical twin pairs were randomized to follow either a vegan or an omnivorous diet for 8 weeks. Both diets were whole foods-based, minimally processed, healthy diets. Participants received pre-made meals delivered to their home for the first 4 weeks of the study. They then prepared their own meals for the last 4 weeks. Health educators provided instructions and support throughout the study so the participants ccould achieve high adherence to their prescribed diets. Participants completed 3 in-person clinic visits, and provided stool and micro-samples of blood from home. Changes in food patterns and behaviors, dietary intake assessment, food satisfaction, as well as gastrointestinal symptoms, psychosocial factors and physical activity were assessed using multiple tools.

Conclusions

The findings of this study indicate that a healthy vegan diet improves cardiovascular health. Vegan eaters’ LDL cholesterol dropped on average by 15.2 milligrams over eight weeks. In contrast, the omnivore participants' LDL cholesterol fell by 2.4 milligrams over eight weeks. Vegan participants shed an average of around 4 more pounds than omnivores, and their insulin dropped by 20 percent more.