How much meat is healthy? Study reveals a sobering reality

Lab-grown or plant-based meat might be making more and more headlines, but plenty of Americans are still chowing down on the real thing. New research shows that you don't even have to be a die-hard carnivore to fall prey to meat's downsides — especially if you are eating specific amounts of specific animals.‌‌

A study published Monday in JAMA Internal Medicine links two servings of red meat or poultry per week to higher rates of heart disease and premature death. The only kind of meat in this study that was not associated with cardiovascular disease or death was fish.

People who ate two servings of processed red meat (think hot dogs, or bacon) per week had 7 percent higher risks of heart disease. Unprocessed red meat was linked to 3 percent higher rates of heart disease and poultry was linked to a four percent higher risk of heart disease.

Ultimately, red meat came out with the worst report card: Eating either processed or unprocessed red meat was also linked to a 3 percent higher chance of death from any cause.

These effects may seem small, but keep in mind that they were estimated assuming that people consumed meat only twice per week. The takeaway, says Victor Wenze Zhong, the study's first author and a nutritional epidemiologist at Cornell University, is that there's no truly risk-free way to eat red meat.

"The increased risk associated with eating these animal protein foods, particularly processed meat and unprocessed red meat, is small, but important," Zhong tells Inverse.

"Our study did not find a safe consumption amount for unprocessed red meat and processed meat. Only zero consumption was associated with no increased risk of heart disease and premature death."

No "safe" amount of meat

This study is based on diet information collected 29,682 people pooled from previous studies conducted between 1985 and 2002.

To get a sense of how much meat people were eating, consider that one serving of meat was defined as about four ounces of unprocessed red meat (about the size of a deck of cards), three ounces of fish (the size of a checkbook).

Then, the team followed up with those participants in 2016 to see how their health had faired since then.

Two red meat or poultry servings per week were linked to premature death and heart disease regardless of how that meat was processed. But, like other studies in the field, this study can only show that there's a link between red meat and premature death. It doesn't prove that meat causes any of these negative consequences.

Zhong adds that the study is based on a larger and more diverse sample than previous studies, and accounted for a number of other variables that past studies have neglected, like whether people drank lots of soda, or didn't exercise (amongst others).

Fortunately, cutting back on meat is one of the easier behavior changes you can make, health-wise. For those who may struggle with change, solutions are taking shape: from meat-patches to gentle flexitarian transitions away from meat.

Eating behavior, Zhong says, is modifiable. He argues that modifying how much one eats meat could be an important dietary strategy that can reduce cardiovascular disease and premature death at a population level.

The drama of red meat science

This study joins numerous others in pointing to the downsides of eating red meat, whether that be increasing the risk of cancer to the risk of heart disease. It also comes on the heels of a recokning within the world of meat science.

If you're a meat enthusiast, you might remember headlines from October 2019 suggesting that the dangers of meat consumption were overblown. That study, a meta-analysis of several other studies, reccomended that most adults don't actually need to change the amount of meat they eat to protect their health.

However, that study was far from as conclusive as it appeared. Its methods were criticized, and some members of the research group failed to disclose ties to beef industry funding.

Meanwhile, outside the relam of that study, evidence against meat consumption has accumulated, Zhong's study included. This study, like others before it, also "support current dietary guidelines that recommend low or no intake of unprocessed red meat and processed meat," says Zhong.

That said, this study still falls into a few of the pitfalls of nutrition science.

It's hard to get people to accurately report what they're eating. And it's possible that people may have changed their dietary habits in the decades since they first reported them, and when the team analyzed their health. This study can't account for those changes.

But, if you ask Zhong, the collective take-home message can still be crystallized.

Red meat probably isn't doing your health, or the planet, any favors. But "any amount of reduction" in red meat eating is still better than no reduction at all.

Partial Abstract:

Results Among the 29 682 participants (mean [SD] age at baseline, 53.7 [15.7] years; 13 168 [44.4%] men; and 9101 [30.7%] self-identified as non-white), 6963 incident CVD events and 8875 all-cause deaths were adjudicated during a median (interquartile range) follow-up of 19.0 (14.1-23.7) years. The associations of processed meat, unprocessed red meat, poultry, or fish intake with incident CVD and all-cause mortality were monotonic (P for nonlinearity ≥ .25), except for the nonmonotonic association between processed meat intake and incident CVD (Pfor nonlinearity = .006). Intake of processed meat (adjusted HR, 1.07 [95% CI, 1.04-1.11]; adjusted ARD, 1.74% [95% CI, 0.85%-2.63%]), unprocessed red meat (adjusted HR, 1.03 [95% CI, 1.01-1.06]; adjusted ARD, 0.62% [95% CI, 0.07%-1.16%]), or poultry (adjusted HR, 1.04 [95% CI, 1.01-1.06]; adjusted ARD, 1.03% [95% CI, 0.36%-1.70%]) was significantly associated with incident CVD. Fish intake was not significantly associated with incident CVD (adjusted HR, 1.00 [95% CI, 0.98-1.02]; adjusted ARD, 0.12% [95% CI, −0.40% to 0.65%]). Intake of processed meat (adjusted HR, 1.03 [95% CI, 1.02-1.05]; adjusted ARD, 0.90% [95% CI, 0.43%-1.38%]) or unprocessed red meat (adjusted HR, 1.03 [95% CI, 1.01-1.05]; adjusted ARD, 0.76% [95% CI, 0.19%-1.33%]) was significantly associated with all-cause mortality. Intake of poultry (adjusted HR, 0.99 [95% CI, 0.97-1.02]; adjusted ARD, −0.28% [95% CI, −1.00% to 0.44%]) or fish (adjusted HR, 0.99 [95% CI, 0.97-1.01]; adjusted ARD, −0.34% [95% CI, −0.88% to 0.20%]) was not significantly associated with all-cause mortality.

Conclusions and Relevance These findings suggest that, among US adults, higher intake of processed meat, unprocessed red meat, or poultry, but not fish, was significantly associated with a small increased risk of incident CVD, whereas higher intake of processed meat or unprocessed red meat, but not poultry or fish, was significantly associated with a small increased risk of all-cause mortality. These findings have important public health implications and should warrant further investigations.