By Dr. Philip Ovaida
As a heart surgeon, one of my favorite mantras is “hit your protein goal.” That’s because many of the patients who walk into my office see enormous metabolic improvements just by swapping dietary carbs for protein.
But maybe you’ve seen research talking about the unhealthiness of high-protein diets. Will getting rid of carbs increase your risk of a heart attack? Or will the amino acids in meat trigger cardiovascular disease?
From a purely scientific standpoint, probably not.
But I’ll go through the research so you can decide for yourself.
What science says about protein and the heart
Let’s start with the studies sounding the alarm about getting ‘too much’ protein in your diet.
One posited that eating more than 22% of your calories from protein could raise cardiovascular and metabolic health risks.
Another found that “high-protein diets increase cardiovascular risk by activating macrophage mTOR to suppress mitophagy.” In other words, that high protein intake could overstimulate certain immune cells, leading to artery damage and higher cardiovascular risk.
Here’s a quick breakdown of their hypotheses:
- Eating a large amount of protein in one sitting raises amino acid levels in your blood.
- Those amino acids collect in artery plaque, or the fatty buildups that encourage atherosclerosis.
- Inside the plaque, amino acids activate a signaling pathway in immune cells called macrophages (specifically called the mTOR pathway).
- When this happens, types of white blood cells called macrophages stop clearing out damaged parts of cells.
- These damaged cells die off, which makes artery plaque more unstable. This means it could rupture and cause heart attacks or strokes.
So researchers concluded eating more than 0.8 grams of protein per kilogram of body weight could be harmful to your heart.
Now, before you start wondering if going vegan is your only option, I’d like to point out a few limitations.
- Most studies don’t control for the type of protein consumed. After all, there’s a big difference between eating a grilled chicken breast and a 10-count chicken nugget meal from a fast food franchise. Food quality matters, especially with protein, although many studies neglect this or don’t define it explicitly in their results.
- Many mechanistic studies use isolated amino acids such as leucine or protein powders to measure protein impacts. However, we know the body doesn’t process amino acids from a whole steak or lentils the same way it processes them from supplements. Leucine in these studies may not act the same way in whole, real foods, since fiber, fat, and other nutrients slow absorption and change digestive impacts.
- Mice don’t develop heart disease the same way humans do, so what causes atherosclerosis in mice doesn’t always translate to people. Look back at that study hypothesizing a higher risk of atherosclerosis from high protein. That number was present in a cohort of mice, not people.
- Increased signaling in immune cells isn’t the same as a greater number of heart attacks or plaque buildup in the body. As one study found: “protein ingestion has a negligible impact on whole-body amino acid oxidation.” Biological reactions may not always translate to risk.
For all these reasons, among many others, we lack concrete data to say high-protein diets are “bad” for the heart. High protein may actually be critical to those recovering from heart attacks or reclaiming metabolic health.
One study found that high-protein diets improve weight loss, reduce triglycerides, and improve HDL cholesterol, all of which are protective for the heart.
We also also know people lose muscle mass and bone density due to inactivity and inflammation after a heart attack. A higher protein intake can help maintain this lean body mass, which supports exercise tolerance and recovery moving forward.
This complements yet another study: higher protein intake after a heart attack may improve long-term patient prognosis. According to their analysis, heart attack patients eating high-quality protein had a much lower 10-year cardiovascular risk score compared to patients eating +50% less protein per week.
Why does research say two different things?
First, nutrition science is still quite young. It’s been less than 100 years since we isolated the first vitamin, after all. The science isn’t settled, and there’s still much to learn, so it shouldn’t come as a surprise that we’re still exploring new biomechanisms.
We also have to look at differences in terms and study structure. There’s a big difference between studying metabolically unwell young people versus metabolically healthy older adults, for example.
And don’t forget that N = 1. One person’s response to protein won’t be the same as someone else’s, especially within unique age, sex, or health cohorts.
But I can confidently say that the benefits of protein far outweigh any warning to the contrary, especially for those recovering from poor metabolic health.
What about all those other problems with protein?
Protein has become quite the target for misinformation. If you’re active on X, you likely know what I mean.
I can’t dispel all protein myths here, but I felt it was appropriate to cover a few topics.
First: most people actually underconsume protein, not overconsume it. Americans have a mean protein intake of 16%, which is less than half the max range of even US food pyramid RDVs.
And no, high protein isn’t bad for the kidneys. If you live with liver and kidney problems, then yes, you may need to plan your meals. But this applies only to a very small portion of the population.
When healthy, resistance-trained adults consume high-protein diets (think 3x higher than recommended daily values), there is no evidence of harmful side effects on kidneys and renal function. You can find details of that in this study and this one.
So please: don’t believe for one second that increasing your protein intake will do more harm than good. If you’re looking to repair, restore, or protect your metabolic health, a high-protein diet will be an incredibly powerful tool.
So will too much protein hurt your heart?
No, not at all. Especially not as part of a metabolically healthy lifestyle.
And if you’re at high metabolic risk, it might be worthwhile to increase your macros.
That means:
- Eating more whole, real animal proteins. I recommend ruminant animals such as beef, venison, buffalo, and lamb, although chicken, turkey, and seafood are excellent choices. I talk through other options in my guide covering the proper way to set a protein goal.
- More non-muscle proteins such as cheese, eggs, and milk. Despite what you may have heard, eating eggs won’t spike your LDL cholesterol and lead to heart disease.
- Supplementing when necessary with convenient protein options. Uncured, less processed options such as meat snacks may be beneficial. You could also opt for protein powders, although I’d recommend those without high quantities of lead.
Following a high-protein diet for better heart health
High-protein diets aren’t a danger to your heart health. For the vast majority of people, it’s one of the best lifestyle changes you could make.
If you’re not sure how to get started, I’ve written quite a few guides. Learn more about using high-protein diets to support your heart health in the following resources:
- Changing biomarkers on ketogenic diets
- Do you need carbs to support your heart health?
- Mastering Protein Course
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