But, she said, "there are a lot of athletes that over-consume protein to build muscle mass. One of the things they don't realize is there's a limit to how much your body can absorb and utilize at once."
When athletes take in too much protein, some gets laid down as fat.
Skolnick shared the story of one athlete who got faulty nutritional advice from his wife's personal trainer. The man ended up consuming twice as much protein as advised for athletes.
"He was eating protein at every meal," Skolnick said. "In between meals, he was pushing the proteins."
Instead of giving him more lean muscle, he put on fat.
Consuming excessive protein may lead to an upset stomach. Relying on protein and cutting back on carbohydrates may produce headaches and low energy.
Skolnick said the best way for your body to handle protein is in small amounts spread through your day. You might choose eggs, cheese or soy at breakfast; chicken at lunch; fish at dinner; milk or yogurt as a snack.
The general guideline in the current food pyramid for people over the age of 8 is to get 5 to 6 ounces of protein daily from meat and beans, additional protein from two to three daily servings of dairy products, and still more protein from whole grains and vegetables.
An athlete needs at least an additional 3 ounces a day, but a 300-pound athlete may need as much as 26 ounces of daily protein, Skolnik said.
Generally, sedentary people should get .8 to 1.2 grams of protein for every kilogram of their body weight.
"You can easily double it without any trouble, and triple it without any trouble," Ayoob said. "There's a margin of error the body builds in."
Protein bars and shakes usually are made from whey or casein, which are milk products, or from eggs or soy.
"There's nothing wrong with those," said Skolnik. But if you're already eating animal protein, "why do you need a protein shake on top of it?"
As a sports nutritionist, she recommends bars and shakes "as a part of recovery, after a good workout."
Although it's hard to sustain a very high protein diet for a long time, the bigger issue with that kind of eating becomes "what you're pushing out," Ayoob said.
Someone who is eating steak three times a day, or living on protein bars and shakes, probably isn't eating a lot of fruits and vegetables, and may be missing out on all-important fiber.