Here is an example of a research commentary that misses the forest for the trees: "Vegetarians experience a 36 percent lower prevalence of metabolic syndrome than non-vegetarians, suggests new research ... Because metabolic syndrome can be a precursor to heart disease, diabetes, and stroke, the findings indicate vegetarians may be at lower risk of developing these conditions. Metabolic syndrome is defined as exhibiting at least three out of five total risk factors: high blood pressure, elevated HDL cholesterol, high glucose levels, elevated triglycerides, and an unhealthy waist circumference. ... while 25 percent of vegetarians had metabolic syndrome, the number significantly rises to 37 percent for semi-vegetarians and 39 percent for non-vegetarians. The results hold up when adjusted for factors such as age, gender, race, physical activity, calories consumed, smoking, and alcohol intake. ... On average, the vegetarians and semi-vegetarians were three years older than non-vegetarians. Despite their slightly older age, vegetarians had lower triglycerides, glucose levels, blood pressure, waist circumference, and body mass index (BMI). Semi-vegetarians also had a significantly lower BMI and waist circumference compared to those who ate meat more regularly." Given the broader context of what is known about the effects of body fat on long-term health, the plausible mechanism here looks to be related to the amount of visceral fat rather than anything to do with diet per se.

Link: http://www.eurekalert.org/pub_releases/2011-04/llua-vmb041311.php