It's not what you'd expect.

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Bacon is delicious and all, but meat may not be the key to a breakfast that sticks to your ribs. Instead, there's a new study out suggesting that veggie-based proteins—specifically, beans and peas—might actually fill you up and keep you satisfied longer than animal protein. And they can help you lose weight!

We've known for a while that proteins go a long way to helping us achieve that full feeling we need to get us through to lunch. But the idea that plant-based proteins may actually be more effective at satiating hunger than meat is quite new.

Researchers from the University of Copenhagen in Denmark served 43 young men three different breakfasts—a high-protein meat pattie, a high-protein legume pattie and a low-protein veggie pattie made with potato—over the course of several weeks and asked them to report how hungry they felt three hours later. They were then served lunch and told to eat as much, or as little, as they wanted.

On days when participants ate the high-protein legume patty, they ate 13% fewer calories at lunch than on days they had the lower-protein patty. And even though both high-protein patties had the same amount of protein, participants still ate 12% fewer lunch calories when they had legumes for breakfast versus meat.

So what gives beans their power? Researchers say it's in the fiber.

"The protein-rich meal composed of legumes contained significantly more fiber than the protein-rich meal of pork and veal, which probably contributed to the increased feeling of satiety," explains head researcher Professor Anne Raben of the University of Copenhagen's Department of Nutrition, Exercise and Sports. "It is somewhat contrary to the widespread belief that one ought to consume a large amount of protein because it increases satiety more," Raben adds. "Now, something suggests that one can eat a fiber-rich meal, with less protein, and achieve the same sensation of fullness."

Looking to add some more beans to your diet? Check out our list of 36 delicious green bean recipes and get snapping!