Thanks to research suggesting they are better for heart health than animal-based foods, many carnivores are on the hunt for the best plant-based meat replacements they can find.

That may explain the increase in popularity of plant-based burgers in fast-food restaurants and grocery stores. But nutritionists say legumes may be a better option.

Lentils, peas, chickpeas, beans and nuts are natural sources of protein and fiber that are a healthy alternative to highly processed meat substitutes.

"The protein in meat is of high biological value, but the protein in legumes is also good quality protein," said Penny Kris-Etherton, a nutrition professor at Pennsylvania State University.

"As a nutritionist, what really concerns me is the overall nutrient composition of these plant-based meat substitutes that are sweeping the marketplace. They are really high in sodium. They're high in saturated fat. And they're high in calories."

Legumes, which actually are the seeds of plants from the legume family, are considerably healthier. They're linked to a reduced risk of heart disease and lower cholesterol levels. Plus, their high fiber and protein contribute to satiety – which means they help you feel full, so you eat less.

"For people who don't want to eat meat, what I would recommend is legumes cooked in a healthy way – rather than these plant-based substitutes," Kris-Etherton said. "A plant-based diet can be very healthy. A plant-based diet can be very unhealthy, too."

It's important to know legumes also contain lectins, which can interfere with the absorption of calcium, iron, phosphorus and zinc. But lectin is typically reduced during cooking, especially with wet, high-heat methods like boiling or stewing, or soaking legumes in water for several hours.

So, if you're preparing dried beans, it's wise to rinse them first, then soak them for as long as four hours. Afterward, beans should be boiled in water roughly three times their volume, then left to simmer until tender.

It's worth noting beans and other legumes have been commonly – and occasionally comedically – linked to flatulence because they contain high amounts of dietary fiber and carbohydrates that are difficult to digest.

"Don't just all of a sudden eat a bunch of these legumes because you've heard they're great and heart-healthy," Kris-Etherton said. "The way that you cook them as well can help make them less gas-producing."

A trio of studies published in the journal Nutrition concluded the concern over beans' gas production may be exaggerated and that each person can respond differently to different bean types. Still, to help lower the amount of potential intestinal gas and improve the nutritional quality, food researchers suggest discarding the water the beans are soaking in and cooking in fresh water.

Because legumes come in so many different forms, there are a variety of ways to add them to your diet: puree them into dips and spreads, for example, or snack on a handful of nuts instead of potato chips.

"Mix them up in your diet, and they'll keep you interested," Kris-Etherton said. "Add some chickpeas to your salad. Use them as a side dish. Rather than potatoes and rice, use some mixed beans as your sides, and then finally, use them as your main entrée instead of a meat dish.

"It's not just that you're adding something good to your diet; if you do it as a good substitution, you're eliminating something that is unhealthy."

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