By almost any measure, meat alternatives are rapidly gaining in popularity.

The explosion of innovation in plant-based meat alternatives is evident along grocery store aisles and on restaurant menus – and the products aren't only for vegetarians and vegans. Nielsen data show 98% of people who buy meat alternatives also buy meat.

But whether people are choosing so-called alt-meats for ethical or health reasons, they should be careful to compensate for the loss of nutrients, experts say. That goes double for people moving away from animal products entirely.

"You do have to be more intentional about it," said Jo Ann Carson, a retired professor of clinical nutrition at UT Southwestern Medical Center in Dallas. "People can easily find protein elsewhere, but if they're not having any animal products – if they're not having any dairy, meat or eggs – they might have a hard time getting enough grams of protein in the foods they're eating."

For example, regular tofu contains about 8 grams of protein per 100 grams. The same amount of ground beef includes about 19 grams of protein, and ground chicken contains about 17 grams. Federal dietary guidelines recommend 10% to 35% of daily calories come from protein. That's equivalent to 46 grams of protein a day for adult women and 56 grams for adult men.

But there's more to meat consumption than just protein.

"Iron from beef is very well absorbed, but plant iron not so much so," said Mary Ellen Camire, a professor of food science and human nutrition at the University of Maine. "The big thing is vitamin B12 because you can only get that from animal products or supplements. So for some people, that is a risk factor. They may be at risk for developing anemia."

According to restaurant consulting group Baum+Whiteman, 31% of Americans practice meat-free days, and 83% say they're adding plant-based foods to their diets to improve health and nutrition. But in the case of many alternative meats, perception may not mirror reality.

"Using vegetable-based meat substitutes, you typically are eating food that is more processed," Carson said. "I don't think we know all of the ramifications of that."

People should be aware of the tradeoffs if they choose meat alternatives for health reasons, Camire said.

"A lot of them are designed so that they are more comparable to some of the more structured proteins, but they're a blessing and a curse," Camire said. "It might have as much protein as the real meat, but it probably has a lot more sodium, and it may even have more saturated fat.

"Some of the fake burgers are actually putting little globs of coconut fat in there to make it juicy when you bite into it."

According to news reports, many new meat substitutes smell, feel and even "bleed" like meat because they are genetically engineered or highly processed.

"It's a little bit ironic today, when everyone is wanting clean labels, that some of these meat alternatives actually have a lot of additives in them," Camire said.

Beans and legumes such as chickpeas, lentils and soybeans can be a healthy alternative to meat, she said. In addition to protein, they are good sources of other nutrients such as fiber and iron.

In general, as with most dietary choices, the key is to strive for a balance between animal products, fruits, vegetables and other dietary choices that satisfy nutrition requirements, Camire said.

But that's challenging, she added, because "moderation and variety are not sexy topics."

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