A new study on mouse reveals that consuming high protein diet spurs unstable plaque, the kind which leads to blocked arteries. And more plaque build-up in the arteries increases the risk of a heart attack. The new study was published in the journal Nature Metabolism. The mice on the high-fat, high-protein diet developed worse atherosclerosis -- about 30 percent more plaque in the arteries -- than mice on the high-fat, normal-protein diet, despite the fact that the mice eating more protein did not gain weight, unlike the mice on the high-fat, normal-protein diet. The researchers found that certain amino acids, especially leucine and arginine, were more potent in activating mTOR -- and derailing macrophages from their cleanup duties, leading to cell death -- than other amino acids.