An Olympic gold medalist swimmer said he lost muscle on a vegan diet because it was hard to get enough protein

• British swimmer Adam Peaty said he tried being vegan but lost muscle.
• It's harder to consume enough protein with a plant-based diet, but not impossible, experts say.
• The key to a balanced vegan diet is to combine protein sources with other foods, dietitian Ro Huntriss told Insider.

Olympic swimmer Adam Peaty said going vegan made him lose muscle.

Peaty, who swims for Great Britain, told UK news site Joe that he tried being vegan in 2018 but found it too hard to incorporate enough protein into his diet.

"It's hard to understand how much protein you need. For me, I need meat to get enough protein," Peaty, 26, said. "It's a hard diet to adjust to. It's just too hard with the amount of muscle I have to sustain."

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The 6'3" tall swimmer consumes no more than 6,000 calories a day, and said he would eat more plant-based foods if he didn't train so hard.

"I'm a big guy so I do need a lot of protein," Peaty said. "Sometimes I will swap meat for a vegetarian option - I think it's important to branch out and explore different options."

It's harder to build muscle as a vegan, but not impossible

Bodybuilders Torre Washington and Dusan Dudas have both spoken to Insider's Gabby Landsverk about how they've built muscle on a vegan diet.

However, it's more challenging to eat high protein on a plant-based diet than as an omnivore, dietitian Ro Huntriss told Insider.

"Animal-based sources of protein like dairy products, eggs, and meat are termed 'high-quality' sources of protein, meaning they contain all nine essential amino acids," Huntriss said.

"Amino acids are our body's building blocks. If you eat animal products, it's easy to get all of the amino acids we require for muscle growth with little thought."

Plant-based proteins, however, are regarded as 'lower-quality' protein sources.

Vegans need to combine protein sources

As a vegan, you need to consume a variety of plant-based protein sources and combine those with other foods to ensure you get all the essential amino acids you need, according to Huntriss. Eating rice with beans, for example, would work together to equal a compete protein source.

"Soy products are the most nutritionally equivalent in terms of protein quality to animal-based products," Huntriss said. But you generally need to consume large quantities of these foods to get the same amount of protein.

While one 150g chicken breast contains 36g protein and 159 calories, you would need to eat 450g tofu to get the same amount of protein, or 315 calories worth.

While this may not be an issue for an athlete struggling to eat enough, people trying to lose weight on a vegan diet would need to keep an eye on their overall calories in order to stay in a deficit.

Active people should aim to consume 20g of protein plus carbs after exercise

After working out, it's important to refuel, ideally combining carbs and protein, regardless of diet.

"Consuming 20g of protein alongside a source of carbohydrate can promote muscle recovery and growth," Huntriss said. "Good sources of plant-based protein includes tofu, legumes, beans, quinoa, lentils, chickpeas, peas, nuts, seeds, and grains. A vegan protein powder can also be a useful addition."

Huntriss say it's important to learn about nutrients before embarking on a vegan diet to ensure you eat enough to fuel an active lifestyle.

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"Those who are more active require a higher amount of calories," she said. "This can be done in a healthy way by incorporating calorie-rich foods into the diet such as avocados, extra virgin olive oil, nuts, nut butters, and seeds.