Vegan Diet vs. Low-Fat Diet: A Two-Year Weight Loss Trial

Vegan Diet vs Low Fat Diet for Long Term Weight Loss Summary of scientific article by Gabrielle M. Turner-McGrievy, Neal D. Barnard, and Anthony R. Scialli

A 2007 study compared a low-fat vegan diet to a more moderate low-fat diet to see which was better for losing weight and keeping it off long term. The study included 62 overweight postmenopausal women split into a vegan group who avoided all animal products, and a low fat group who followed an older set of mainstream nutrition guidelines.

After following their assigned diets closely for 14 weeks, the women were monitored for weight changes over the next two years. They received either no diet support or occasional group support meetings. The study found that:

• The vegan women lost significantly more weight at both 1 and 2 year checkups compared to the low fat group - nearly 5 lbs more weight loss at 1 year. The vegan diet likely contained fewer calories due to exclusion of high fat animal foods.

• Regardless of diet, women who received group support meetings were more successful at maintaining weight loss 1-2 years later than unsupported women. Attending more meetings strongly predicted sustained weight loss.

• Reported dietary adherence made little difference overall, except vegan diet adherers lost more weight than non-adherers by year 2. But even non-adherers tended to lose weight, suggesting they still improved their diets.

In summary, this well controlled study suggests a low fat vegan diet may offer advantages for long term weight loss over a standard low fat diet in postmenopausal women. The social support from group meetings also clearly helps sustain weight loss over time regardless of diet type. The study demonstrates both the impact of diet composition itself and the value of education plus support in combating obesity.

Turner-McGrievy, G. M., Barnard, N. D., & Scialli, A. R. (2007). "A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet." Obesity, 15(9), 2276-2281. Available at: https://onlinelibrary.wiley.com/doi/epdf/10.1038/oby.2007.270