When people think about protein, meat, chicken, eggs and milk usually come to mind first. But the Brazilian plate has a plant protein source that shows up almost every day: beans. And they have company: lentils, chickpeas, peas, soy and tofu add up too.

In this article, you’ll see what studies say about plant protein and lean mass, and practical ideas for using these foods during treatment with a GLP-1 medication, whether you’re vegetarian or not.

Legumes as a protein source

The short version of the Dietary Guidelines for the Brazilian Population, from Brazil’s Ministry of Health, notes that legumes, such as beans, lentils and chickpeas, are sources of protein, fiber, B vitamins and minerals. In other words, they help on two fronts that deserve attention when you’re eating less: protein and fiber.

The 2014 Dietary Guidelines also note that, in Brazil, rice is usually eaten together with beans, a combination that’s a staple on our table.

According to the Brazilian Food Composition Table (TACO), 100 g of cooked carioca beans (pinto beans) have about 4.8 g of protein. That’s less than meat, which is why legumes tend to go further when they show up at several meals a day or in generous portions, whenever your appetite allows.

Does plant protein help preserve lean mass?

It’s a common question, and a few studies help answer it.

A 2018 meta-analysis pooled studies of people doing strength training and taking protein supplements. It concluded that soy protein produced gains in strength and lean mass similar to those from whey protein.

Another meta-analysis, from 2021, compared animal and plant protein in randomized trials. Overall, protein source didn’t change absolute gains in lean mass or strength. The authors found an advantage for animal protein in percent lean mass, concentrated in adults under 50, and concluded that animal protein tends to be more beneficial for lean mass, especially in younger people.

These studies have limits, and many of them looked at supplements rather than everyday food. But they suggest plant protein can be part of looking after lean mass, ideally together with strength training and a variety of sources.

Where plant protein is found

Beans of every kind. Pinto, black, black-eyed, white, cranberry.
Lentils. They cook fast and don’t need soaking.
Chickpeas. In salads, stews or as a spread (hummus).
Peas. Fresh, frozen or dried.
Soy and soy foods. Tofu, soy milk and textured soy protein.
Peanuts, nuts and seeds. They add protein, but also quite a bit of fat, so keep portions small.

Practical everyday ideas

With a small appetite, legumes can be easier to eat in soft preparations:

Bean broth. A cup of broth with mashed beans often goes down better than a full plate.
Lentil soup with vegetables, which can also include shredded chicken if you eat meat.
Hummus on bread, toast or with carrot and cucumber sticks.
Tofu scramble with tomato and seasonings, instead of scrambled eggs, if you don’t eat eggs.
A warm chickpea salad with cooked vegetables.
Beans with an egg, if you eat eggs: both sources together add more protein to the same plate.

Combining sources helps

If you’re not vegetarian, the idea isn’t to choose between animal and plant protein, but to make the most of both. Rice, beans and a portion of meat, chicken, fish or egg is still a simple, very Brazilian combination.

If you’re vegetarian or vegan, it’s worth varying your sources a lot through the day and talking with a dietitian. Some diets without animal foods may call for attention to nutrients such as vitamin B12, and a professional can guide you on what makes sense in your case.

If legumes cause discomfort

Beans, lentils and chickpeas have a lot of fiber and can cause gas, especially when you add a large amount all at once. A few strategies often help:

Increase the amount gradually over the weeks.
Cook them well until they’re soft.
Drink water throughout the day.

If the discomfort is strong or persistent, talk with your doctor or dietitian.

The right amount is individual

The ideal amount of protein depends on your weight, age, routine and health. People with kidney disease, for example, may have different recommendations. Your target should be set with your doctor or dietitian.

Tracking helps

Writing down your meals for a few days helps you see how much of your protein comes from plant sources and where you could add more variety. These notes are also useful to bring to your appointment.

Beans on the plate are a Brazilian tradition that, as a bonus, helps add up protein and fiber. It’s worth making the most of it.

Sources

Messina M, et al. No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise. International Journal of Sport Nutrition and Exercise Metabolism, 2018.
Lim MT, et al. Animal Protein versus Plant Protein in Supporting Lean Mass and Muscle Strength: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 2021.
Brazilian Ministry of Health. Dietary Guidelines for the Brazilian Population: short version. 2018.
Brazilian Ministry of Health. Dietary Guidelines for the Brazilian Population. 2nd edition, 2014.
Center for Studies and Research in Food (NEPA/Unicamp). Brazilian Food Composition Table (TACO). 4th edition, 2011.

Plant protein: beans, lentils, chickpeas and tofu