A recent systematic review and meta-analysis of randomized controlled trials published in the journal Clinical Nutrition found that vegetarian-style dietary patterns (from vegan, which omits all animal products, to ovo-lacto-vegetarian, which includes eggs and dairy) may be helpful in diabetes management.
The nine trials included in the analysis followed 664 predominantly middle-aged, overweight or obese participants with type 2 diabetes controlled by medications for a mean of 12 weeks. The evidence suggested, with moderate certainty, that a vegetarian dietary pattern improved glycemic control, cholesterol levels, and body weight in individuals with diabetes in comparison with a mix of different non-vegetarian dietary patterns, including conventional diabetic diets and usual American diets.
The authors suggest that the high content of fiber, unsaturated fats, and phytochemicals in a vegetarian diet may help explain observed benefits. These results highlight the importance of basing a vegetarian eating plan on sources of these beneficial compounds (like whole grains, legumes, vegetables, fruits, nuts, and seeds), not on refined grain products and sweets.