If you want to choose meat that's better for your heart, substitute plant-based burgers for the real thing, a new study out of Stanford University found.

"A diet that includes an average of two servings of plant-based meat alternatives lowers some cardiovascular risk factors compared with a diet that instead includes the same amount of animal meat," according to the study by Stanford Medicine scientists. "Swapping out red meat and eating plant-based meat alternatives lowered some cardiovascular risk factors over the eight-week study," according to researchers at Stanford Medicine.

The study set out to answer, "Are meatless meats any healthier than the real thing?"

Since meatless burgers like Beyond Meat contain relatively high levels of saturated fat and added sodium and are considered highly processed foods, many consumers have asked: Are meat substitutes any better than meat? When it comes to avoiding processed foods, a diet of whole foods that is mostly plant-based appears to be the healthiest. Still, the question remains: Which is better for you: Meatless burgers or the real thing? This study appears to settle the question.

Beyond Meat is made with pea protein, as well as pressed canola oil, refined coconut oil, rice protein, cocoa butter, mung bean protein, and methylcellulose, potato starch, apple Extract, pomegranate extract, salt, potassium chloride, vinegar, lemon juice concentrate, sunflower lecithin, beet juice extract. Many consumers question whether all these ingredients add up to a less healthy alternative to meat.

The reason for choosing a plant-based burger is often to be healthier, so consumers consider the "like meat" factor of Beyond versus the "less meat-like" taste of a veggie burger against health considerations since while "veggie burgers" are less like the real thing, they are considered healthier and contain more recognizable plant-based ingredients such as: Carrots, onions, beans, zucchini, peas, spinach, corn, broccoli, red peppers, roasted garlic, beets, mushrooms,  lentils–in some combination. Choosing the right burger pattie for you is a personal choice, but many people who prefer the lifelike taste of real meat choose Beyond or Impossible burgers over veggie burgers, as a way of not missing their craving for meat.

Half the participants ate meat, the other half meatless, for eight weeks, then switched

“There’s been this sort of backlash against these new meat alternatives,” said Christopher Gardner, PhD, professor of medicine at the Stanford Prevention Research Center. “The question is, if you’re adding sodium and coconut oil, which is high in saturated fat, and using processed ingredients, is the product still actually healthy?” To find out, Gardner and his research team asked 30 individuals to follow two different diets for 16 weeks: One called for at least two servings of red meat a day, the other for two servings of plant-based meat a day.

After just 8-weeks on the alternative meat diet three findings were significant:

  • Participants’ levels of LDL cholesterol (aka bad cholesterol) dropped on average 10 milligrams per deciliter, which is clinically significant.
  • Participants lost 2 pounds on average, during the plant-based portion of the study
  • Plant-based meats helped reduce TMAO levels, which is known to be linked to cardiovascular disease. TMAO levels were lower when study participants were eating plant-based meat and stayed lower after they switched back to meat.

The marker that the researchers measured was TMAO, or trimethylamine N-oxide, which is known to be a precursor to plaque deposits and hardening of the arteries that is a sign of cardiovascular disease. High levels of TMAO have been linked to cardiovascular disease over time. The dieters who ate plant-based meat and avoided the red meat were lower when the study ended.

The study asked 36 participants to follow a diet of either meat or plant-based alternatives for a total of 16 weeks–eight one way and then they swapped for the next eight. Called a "cross over study, for eight weeks, half of the participants ate the plant-based diet, while the other half ate the meat-based diet consisting of primarily red meat, although some participants ate some chicken as well. Then they switched. Both groups had two servings of meat or plant-based alternatives per day, logging their meals and checking in with the researchers to record their progress.

The team worked with Stanford's Quantitative Sciences Unit to analyze the data after the16-weeks. “The QSU helped us draw up a statistical analysis plan, which we published online before the study was completed,” Gardner said. “That way our plan was public, and we were accountable for the specific primary and secondary outcomes that we had initially said we wanted to go after ... the levels of TMAO, blood cholesterol, blood pressure and weight.”

Measuring TMAO is like looking into a crystal ball for cardiovascular disease

The main outcome the team was interested in tracking, Gardner said, was the level of TMAO which is considered to be “an emerging risk factor,” for heart disease. scientists now believe there is a connection between high levels of TMAO and increased risk of cardiovascular disease, but the connection has yet to be proven. Two precursors to TMAO, carnitine, and choline, are found in red meat, so it makes sense that those who eat it have higher levels.

“At this point, we cannot be sure that TMAO is a causal risk factor or just an association,” Gardner said. However, more doctors are testing patients for TMAO as a crystal ball to see who will develop cardiovascular disease and who won't. Recent studies have shown that high levels of TMAO co-exist with inflammation, the build-up of plaque, and the hardening of the arteries. High levels of TMAO raise the risk of cardiovascular events such as heart attack and stroke by 60 percent, other studies have shown.

Something weird happened when the two groups switched back. TMAO stayed low

In the Stanford study, participants eating red meat for the first eight-week phase had an increase in TMAO, while those who ate the plant-based meat in the first eight weeks did not. When the groups switched diets and the group that had been eating meat twice a day switched to a plant-based diet, they showed a decrease in TMAO levels. But the strange thing was that when while the group that had been eating plant-based switched to meat, they did not see an increase in TMAO, suggesting that there might be some lingering protection.

“It was pretty shocking," Gardner said. "We had hypothesized that it wouldn’t matter what order the diets were in. It turns out that there are bacterial species responsible for the initial step of creating TMAO in the gut. These species are thought to flourish in people whose diets are red-meat heavy, but perhaps not in those who avoid meat.

“So for the participants who had the plant-based diet first, during which they ate no meat, we basically made them vegetarians, and in so doing, may have inadvertently blunted their ability to make TMAO,” he said. This has promising possibilities: Doctors could tell their patients with early heart disease to switch to a whole-food plant-based diet to reduce the risk of heart attacks and strokes, but it's too early to know the practical applications of the findings.

Cholesterol levels also benefited from getting off meat and people lost weight

Other health benefits were noted in the participants who ate the plant-based alternatives including lower cholesterol and weight loss. The LDL levels of so-called  “bad” cholesterol went down an average of 10 points, which while not significant, was true whether they ate the plant-based meats first or the animal products first. Those on the meatless meat also lost 2 pounds, on average, during the eight week fun of eating no meat.

“The modest weight loss observed when participants substituted the plant-based meats in place of the red meats is an unexpected finding, since this was not a weight-loss study,” said Anthony Crimarco, Ph.D., the lead author of the study. “I think this indicates the importance of diet quality. Not all highly processed foods are created equal.”

Gardner hopes to continue studying the relationship between health and plant-based meat alternatives, particularly as it pertains to changes in the microbiome. Gardner said he’s also interested in expanding his research into diet patterns overall. “Maybe next we’ll look at a combination of dietary factors on health—perhaps alternative meat combined with alternative dairy products,” he said.

The study concluded: “Among generally healthy adults, contrasting plant with animal intake while keeping all other dietary components similar, the Plant products improved several cardiovascular disease risk factors, including TMAO; there were no adverse effects on risk factors from the Plant products.”

So when you crave meat, choose plant-based options, but when you just want a bun with something healthy to bite into between the lettuce, tomato, and vegan cheese, head to the veggie burger in the frozen food aisle and get yourself a bean burger.

Read the full study results in the American Journal of Clinical Nutrition.