Protein is important for everyone, especially those looking to build muscle through exercise. But the source of that protein is not so important. New research from the University of Illinois shows that plant protein is just as good as animal protein when it comes to muscle protein synthesis.

The animal vs. plant protein question was actually only one of three questions to which researchers were looking for answers. They also wanted to know if it mattered if protein intake was evenly distributed throughout the day and if a moderate but sufficient daily protein intake influenced any of the variables.

The answer was no to all three questions.

"The longstanding belief or the current dogma was that animal-based protein sources were better, particularly for the muscle-building response," said Nicholas Burd, a professor of health and kinesiology at the University of Illinois Urbana-Champaign.

This belief was rooted in science: Previous studies that took muscle biopsies after a single feeding found that an animal-based meal provided more of a stimulus for muscle protein synthesis than a vegan meal, Burd said. "And so, our general hypothesis based on these previous studies was that the animal-based eating pattern would be more effective at supporting the muscle-building response."

Burd thought measurements taken after a single meal might not equate to what happens over time so that was the basis for his research. He and his colleagues also wanted to conduct research regarding the amount and timing of protein intake.

The study involved 40 healthy and physically active 20-40 year-old participants who were randomly assigned to either a vegan or omnivorous diet. Researchers provided all of the meals. Some were eaten in the lab and others at home.

Those in the omnivorous group ate beef, pork, chicken, dairy and eggs and had roughly 70 percent of their protein from animal sources. Those in the vegan group had their amino acid content balanced to ensure a complete protein profile.

All participants engaged in a series of strength-training exercises every three days. They also wore accelerometers to keep track of their activity away from the lab. Muscle biopsies were taken at the beginning and end of the trial to measure results.

"It was thought that it was better to get a steady-state delivery of nutrients throughout the day," Burd said. "I also thought that if you're getting a lower-quality protein—in terms of its digestibility and amino acid content—that perhaps distribution would make a difference. And surprisingly, we showed it doesn't matter."

Now when asked for his recommendation regarding the best protein source for building muscle Burd says, "It's the kind you put in your mouth after exercise. As long as you're getting sufficient high-quality protein from your food, then it really doesn't make a difference."

Click here to read more in the journal Medicine & Science in Sports & Exercise.