Lean Beef Fits Into a Heart-Healthy Diet, Study Shows

Beef is a staple on dinner plates around the world, yet it also sits at the center of an ongoing debate about heart health. Earlier research has linked red meat consumption to an increased risk of cardiovascular disease, but a new study out of Pennsylvania State University — published in the Journal of the American Heart Association — suggests that beef’s effects on your ticker may be more nuanced than previously believed. 

The 2025 study examined heart health indicators and gut microbiome diversity in 30 young, generally healthy adults who cycled through four controlled diets over four weeks, each varying in the amount and type of beef consumed.

Researchers found that eating moderate portions of lean beef as part of a Mediterranean-style diet — rich in plant-based foods like fruits, vegetables, nuts, beans, and whole grains, and low in sweets and processed foods — did not elevate an emerging cardiovascular disease marker. Specifically, those who followed a Mediterranean diet with either 0.5 or 2.5 ounces of lean beef per day showed no increase in trimethylamine N-oxide (TMAO), a metabolic compound associated with higher cardiovascular risk. The study also found that even higher amounts (up to 5.5 ounces per day) did not raise TMAO levels in the context of the Mediterranean diet.

“The study does not suggest eating more red meat, but it supports that modest, lean beef can fit into a Mediterranean-style diet without worsening TMAO or other heart risk markers,” says Michelle Routhenstein, RD, a preventive cardiology dietitian and founder of Entirely Nourished. This research aligns with recommendations from the American Heart Association and Mediterranean diet guidelines, which emphasize fruits, vegetables, whole grains, legumes, nuts, and fish while permitting small amounts of lean, unprocessed red meat, she adds.

However, because the study participants were generally healthy and closely adhered to the provided diet, Routhenstein notes that the results may not apply to higher-risk individuals or real-world settings. Moreover, observational studies still link higher intake of red — particularly processed — meat to increased cardiovascular risk, so more long-term research with a larger sample size is necessary, says Leonard Pianko, MD, a cardiologist and internal medicine physician and founder of Aventura Cardiovascular Center. 

Keep scrolling to better understand beef’s role in heart health.

What is TMAO, and how does it affect cardiovascular health?

Trimethylamine N-oxide, or TMAO, is a compound produced when gut bacteria break down nutrients such as carnitine and choline found in animal products like meat, eggs, and some fish, Routhenstein says. “TMAO is a risk marker rather than a direct cause of heart disease, but its levels are shaped by diet, gut bacteria, kidney function, and lifestyle,” she explains. Higher TMAO levels have been linked to stiffer arteries, more plaque buildup, a higher risk of clotting, and an increased risk of heart problems. 

Are there potential health benefits to eating modest amounts of lean beef?

Lean beef is primarily valued for its high protein content, which plays an important role in building muscle and maintaining strength. It also provides bioavailable zinc, vitamin B2, and other B vitamins that support metabolism, blood function, and energy levels, Routhenstein says.

Furthermore, when lean beef replaces higher-fat meats or refined carbohydrates in a Mediterranean-style diet, it can help maintain or even improve blood pressure, vascular function, and TMAO levels, Routhenstein says. Of course, the potential health benefits of lean beef also depend on what else you’re eating.

“These benefits largely come from the lower saturated fat content of lean cuts combined with the heart-protective effects of fruits, vegetables, whole grains, legumes, nuts, and olive oil in the overall Mediterranean dietary pattern,” Routhenstein explains.

Srihari Naidu, MD, a cardiologist and professor of medicine at New York Medical College, agrees. “This data is particularly timely as there are many people who believe in the benefits of a high protein diet, especially those trying to gain muscle strength and weight, but also want to reduce their cardiovascular risk,” he says. “The new research provides a way to potentially thread the needle by maintaining a Mediterranean diet, while also adding in lean beef at even higher levels than originally thought to be healthy.”

What exactly qualifies as lean meat?

According to Naidu, lean meat is any meat with less than 10 grams of total fat, less than 4.5 grams of saturated fat, and less than 95 milligrams of cholesterol per 3.5-ounce cooked portion.

In this study, lean beef was included as part of a Mediterranean eating pattern alongside fish, poultry, legumes, and nuts, but the study did not directly compare beef to other protein sources. “Research continues to favor fish, legumes, and nuts over red meat for long-term heart health, but modest amounts of lean, unprocessed beef appear neutral when consumed in a high-quality diet,” Routhenstein says.

What are the negative health outcomes associated with high beef intake? 

Regularly consuming more than the recommended amount of lean beef or eating processed meats—especially if your diet is low in fiber and high in sugar—can increase the risk of cardiovascular disease, raise TMAO levels, and reduce beneficial gut bacteria, Pianko says. 

Processed meats like sausages, bacon, and deli cuts are consistently linked to higher risks of heart disease, type 2 diabetes, and premature death, mainly due to their sodium, nitrites, and other additives, Routhenstein explains. Studies also show that eating more beef can trigger inflammation and increase oxidative stress, raising the likelihood of chronic disease.