To investigate, researchers measured a range risk factors, including blood sugar, blood fats, blood pressure, waist size, and body mass. Together when these factors are elevated, they can lead to metabolic syndrome.
Researchers analyzed the diet, health and lifestyles of more than 700 adults.
Using questionnaires on eating habits, the researchers categorized participants as vegetarians (eating meat of any kind less than once a month), semi-vegetarians (eating meat or poultry less than once a week), and non-vegetarians.
The researchers also measured sugar, fat and cholesterol in the subjects' blood as well as blood pressure, waist size, and body mass index.
Researchers found that vegetarians were lower than non-vegetarians on all counts except cholesterol.
Vegetarians' average BMI of 25.7 was four points lower than that of non-vegetarians, who, on average, had BMIs close to 30. Semi-vegetarians fell in the middle, with a BMI and waist size smaller than non-vegetarians, but larger than vegetarians.
Researchers found 23 out of every 100 vegetarians were found to have at least three metabolic syndrome factors, compared with thirty-nine out of every 100 non-vegetarians and 37 out of every 100 semi-vegetarians.
Researchers say they are unsure whether the protective effect is from eating less meat, more plant-based foods, or both.
The study, published in the journal Diabetes Care, did not follow the subjects over the long term to see whether those who abstained from meat actually had lower rates of diabetes or heart disease, so more studies are needed on the subject.