Excessive protein intake may trigger artery damage, cardiologist warns

The gym culture has made protein synonymous with health. Protein shakes line convenience store shelves. Fitness influencers preach the gospel of high-protein diets as the surest path to muscle and leanness. But a growing body of research is complicating that story, suggesting that more protein does not automatically mean a healthier heart—and that for some people, excess protein may quietly damage the very arteries that keep them alive.

Dr. Rahul Mehta, a consultant cardiologist, has begun seeing this tension play out in his practice. A recent study has given him language for what he observes: when protein climbs above roughly 22 percent of a person's daily calories, the body appears to mount an immune response that can accelerate plaque buildup inside artery walls. The mechanism is specific and troubling. High-protein diets elevate levels of an amino acid called leucine, which is abundant in meat, eggs, and dairy. The body's immune cells, called macrophages, are designed to protect tissue. But when exposed to excess leucine, these cells become overstimulated and begin to damage the inner lining of arteries. Over years, this process contributes to atherosclerosis—the narrowing of blood vessels that restricts blood flow and raises the risk of heart attack and stroke.

"This study adds weight to what we see in practice," Dr. Mehta said. "People assume more protein automatically means better health. That's not always true, especially for the heart." The assumption is understandable. Protein is essential for building muscle, repairing tissue, and countless other bodily functions. The problem is not protein itself, but the cultural momentum around it. Most people already meet their protein needs through ordinary meals—chicken at dinner, eggs at breakfast, yogurt as a snack. Yet the supplement industry has normalized adding multiple protein shakes or bars on top of that baseline intake, pushing total consumption into territory that may be harmful.

Dr. Mehta emphasized that certain groups face heightened risk. Anyone with existing heart disease, high cholesterol, diabetes, or a family history of cardiac problems should be especially wary of extreme protein-heavy diets. But younger people are not exempt. Artery damage develops silently over years, with no symptoms to warn the person it is happening. By the time someone feels chest pain or experiences a cardiac event, decades of accumulated damage may already be present.

The message from Dr. Mehta is not to abandon protein. Rather, it is to recalibrate expectations and resist the pull of dietary extremes. A healthy diet distributes calories across proteins, carbohydrates, and fats in measured proportions. Portion control matters more than chasing the protein targets circulating on social media. "Food trends change, but your arteries remember everything," Dr. Mehta said. The implication is clear: eating sensibly today is an investment in heart health tomorrow, and no fitness goal is worth the silent damage that excess protein may inflict on the cardiovascular system over time.