An NFL rookie says he swapped pizza for fish, hummus, and brown rice — now he's starting every game for a Super Bowl contender

• NFL rookie Greg Rousseau is starting for the Buffalo Bills in the later rounds of the playoffs.
• Rousseau said he became more health-conscious in his first NFL season.

NFL rookie Greg Rousseau has adapted from a college lifestyle to an NFL lifestyle over the past nine months, and his hard work seems to be paying off. The 21-year-old pass rusher has started every game for Super Bowl contender the Buffalo Bills this season, and throughout the playoffs.

At 6-foot-7 and 270 lbs, Rousseau is a powerhouse. But going from playing in the summer heat at the University of Miami to the frigid 7-degree weather of Buffalo — facing players that match or exceed him in physical magnitude — has taken some adjustment.

"Everybody is a monster in the NFL, it's crazy," Rousseau told Insider. "It's a mindset that you have to raise your level of competition. You just got to go harder all in all."

One of the first tweaks Rousseau made to match his teammates and rivals was to his diet.

"You got to eat healthier, you have to take care of your body better off the field, there's so much that goes into it," Rousseau told Insider.

That involved adding more fish and brown rice to his diet, in place of his favorite meals of pizza, lasagna, and other Italian dishes, which he now eats in moderation.

Fish is a popular food among pro athletes — it's loaded with protein and helps to reduce inflammation

Rousseau's large frame puts him at a higher risk of injury than smaller, lighter NFL players, according to a small study by Football Outsiders.

A fish-heavy diet provides some benefits. One serving of salmon, tuna, or swordfish, and can account for 41% of a person's recommended daily intake of protein, according to the US Department of Agriculture.

Fatty fish is loaded with vitamins like B3, B5, B6, B12, D, and E, as well as omega-3 fatty acids, selenium, and potassium, which can help reduce inflammation. That anti-inflammatory effect has been linked with heart health and a reduced risk of injury.

Rousseau can look to other examples in the NFL and other sports of fish-heavy diets among fellow big-bodied athletes. The San Francisco 49ers' 267-lb Pro Bowler Nick Bosa, who is also helping his team compete for a Super Bowl in this year's playoffs, also makes fish a priority in his lifestyle, according to NFL Network.

The 6-foot-8, 257-lb NBA star Kevin Love told Insider that he makes fatty fish his primary source of protein, and it's helped him stay on the court to help the playoff-contending Cleveland Cavaliers this season.

Hummus is a cornerstone of Rousseau's diet, and he now has a sponsorship

Rousseau told Insider hummus is his go-to snack every day, scooping it up with pita chips or celery. (He currently favors Ithaca hummus, which is now sponsoring him.)

Hummus, made of chickpeas, contains protein, carbs, fiber, and healthy fats. It is also high in calcium.

"It's not unhealthy, there's not a lot of fat in it, and it's something that's quick and easy to make when you're busy and need a quick snack ... I know that eating right goes a long way for your performance," Rousseau said.