The claim: Fresh off the heels of a study saying that a high-protein diet could have serious health consequences: The journal Nutrition reports that certain animal-based sources of the macronutrient could cause higher levels of inflammation than foods like legumes, nuts, and beans.
The research: Researchers at the University of Navarra in Spain recruited 96 obese adults to follow a reduced calorie diet consisting of either 30% or 15% protein for 8 weeks. Body composition measurements and blood samples were taken at the start and end of the study; vegetable, meat, and fish protein intakes were recorded throughout. After 8 weeks, both groups lost nearly the same amount of weight and fat, but participants who got more of their protein from meat had higher levels of inflammation compared to participants who consumed mostly fish or plant-based sources of protein.
What it means: Inflammation contributes to a number of diseases, such as heart disease, stroke, and cancer. And meat contains several compounds that promote the detrimental process, like saturated fat and iron, says lead study author Patricia Lopez-Legarrea, a nutrition and food science researcher. During the cooking process, high-fat, high-protein animal foods also develop advanced glycation end products (AGEs), which contribute to inflammation and degenerative diseases like diabetes and atherosclerosis.
The bottom line: Researchers are cautious to make general recommendations, since their study was only performed on a small number of adults with metabolic syndrome. Still, it’s a good idea to keep red meat consumption to twice a week or less, and to stick to leaner cuts (like sirloin, flank, or tenderloin steak ), suggests Lopez-Legarrea. “And indeed, we should make an effort to promote the intake of vegetable protein, mainly legumes,” she says. Veggie burger or falafel sandwich, anyone?