What is a Plant-Based Diet?

What foods are allowed on a plant-based diet?

Fruits and vegetables, of course, but also nuts, seeds, oils, whole grains, legumes and beans. The goal, however, isn’t to eat only plants, just mostly plants.

“Try to fill half to three-quarters of your plate with whole foods,” like those listed above, Weinandy says. The rest “can be animal-based like a high-quality protein,” such as fish and chicken as opposed to highly processed meats and animal products like sausage, lunch meat, bacon and hot dogs.  

What about all the plant-based products taking up an increasing amount of space on grocery store shelves? (We’re talking about all the plant-based drinks, meat and dairy substitutes.) Weinandy suggests avoiding them if you’re following a plant-based diet for health reasons (as opposed to animal and/or environmental concerns). 

The reason? Many of the meat substitutes “are highly processed and contain a large amount of saturated fat, which we know increases the risk of high cholesterol and heart disease,” she says. 

If you’re choosing a meat substitute as a way to make sure you get plenty of protein without deviating from your plant-based approach, opt for tofu, legumes or lentils instead. Research shows that all of these are high-quality sources of protein. 

What are the health benefits of a plant-based diet?

Any plant-based eating plan would seem to get an automatic gold star from nutritionists, but it depends on your food choices. If you’re regularly filling your plate with a variety of fresh, whole foods, the health benefits are not unlike other similar plans. A plant-based diet — which essentially includes the Mediterranean Diet, MIND Diet, and DASH Diet — is associated with a reduced risk of heart disease, better diabetes management and prevention, and kidney health, Weinandy says. 

But the health benefits dwindle considerably if you’re filling your plate with highly processed “plant based” foods — you’ll find the phrase printed on the packing of chips, energy bars and meat substitutes. 

Just because something comes from a plant doesn’t make it healthy, says Kristin Kirkpatrick, a registered dietitian for the Cleveland Clinic. Cookies, chips, and sugar-sweetened beverages may all be derived from plants, but that doesn’t mean they’re nutrient dense or benefit health when consumed on a regular basis.” 

Her advice — whether you’ll following a vegan, plant-based or semi-vegetarian diet — is to fill up on nutrient-dense foods and to limit those that are high in sugar and lack fiber. Also important: Make sure you get enough high-quality protein. 

If you’re not sure how much you should be getting on a daily basis, consult a registered dietitian to figure out how much protein you need and how you can make sure you’re meeting that daily quota. Tracking food intake with an app is one way to do that.   

Can you lose weight on a plant-based diet?

A number of studies have linked plant-based diets to a lower BMI (short, for body mass index, an estimate of body fat) and some research suggests that switching to a plant-based diet can help with weight loss, depending on how the diet is followed. While one review of studies, published in the Journal of Geriatric Cardiology, found that it’s effective for weight loss, another suggests the opposite can be true if a plant-based plan relies too heavily on ultra-processed foods. 

“A major reason so many people gain weight and keep that weight on is by eating too many calories from ultra-processed foods which are hyper palatable,” Weinandy says. “Hyper palatable foods like potato chips and ice cream are often hard to eat just a small amount of. When a person limits these foods, they usually take in fewer calories and lose weight.”