In the world of American football, players have gotten big. Really big. It's one of the few sports where players actually lose a lot of weight after they retire. Wide receivers today are commonly the size of linebackers 30 years ago.

The perception is this obesity escalation filters down to college and high school as well, because of a size arms race, but new research suggests that being bigger doesn't mean being better -- and certainly not healthier.

Jeffrey Potteiger, professor of exercise science at Grand Valley State University, and Maggie McGowan-Stinski, senior athletic training major, set out to determine how body size has changed in college and professional football players over the past 70 years.

"We started to take a look at providing the information that sports medicine personnel need to be aware of in order to effectively protect the health of the players under their care," Potteiger said. "In football, the most at-risk athletes are the offensive and defensive linemen."

The research duo determined that players have gained an average of between a quarter of a pound to one-and-a-quarter pound per year since 1942. This equates to an average 60-pound increase in body mass for offensive and defensive linemen.

Potteiger said the most common diseases resulting from excess body mass and body fat, especially around the abdominal area, include high blood pressure, diabetes, cardiovascular disease and metabolic syndrome. He added that hitting the gym and eating more aren't the only ways athletes are attempting to gain body mass.

"The use of growth promoting agents, such as anabolic steroids, growth hormones and insulin carry side effects that range from mild to severe," Potteiger said. "The severity of the side effects is dependent on the dosage level of the growth promoting agents and the length of time the agents are consumed."

To help athletes increase their body size in a healthier manner, Potteiger recommends the following:

• Strive for lean body mass increases of less than one pound per week;

• Maintain good nutritional intake by eating one to one-and-a-half grams of protein for every two pounds of body mass;

• Eat adequate carbohydrates while avoiding excessive calories;

• Perform a resistance training program three-to-five days per week; and

• Leave plenty of room for rest and recovery.

The full study, "Protecting the Metabolic Health of Football Players With High Fat Mass," can be found in Strength and Conditioning Journal.