Defensive linemen crouched on the football field is a familiar sight this time of year, their hulking bodies forming a barrier between the rival teams quarterback and a touchdown. Serving as a human blockade means linemen often weigh in near 300 pounds, with a daily caloric intake that can reach 6000 calories.
I tracked down Jen Ketterly, director of sports nutrition for the University of Georgia Bulldogs, to find out how she ensures the health of her team despite their need for higher body weight.
One step involves determining whether fat or muscle is contributing to weight. Body mass index (BMI) is the most common measurement for judging whether a persons weight could cause health problems, but the formula only takes into account height and weight. The weight of the muscle carried by many football players means their BMIs can easily be higher that whats considered healthy. As this post from PLOS Obesity Panacea blog notes, people with high physical activity can be classified as overweight or obese based on BMI, yet have little fat and a healthy metabolic profile. For example, they may have normal blood pressure and cholesterol levels that dont put them at risk for health problems like heart disease.
What does become useful for us is an assessment of body composition, Ketterly said. That means looking at the amount of fat mass versus the amount of lean mass that a person has on their body.
Fat mass is exactly what it sounds like the percent of body weight that comes from fat while lean mass accounts for everything else.
Ketterly uses a giant, egg-shaped machine called a BOD POD to measure how much of a players body is fat. The player steps inside, and the BOD POD measures body volume by determining the amount of air his body displaces. It calculates body density, which can then be translated into a measure of body fat. 
Weve set time points throughout the course of the season and the course of the academic year that we run these body composition assessments and see how a player is responding to their training and nutrition choices, Ketterly said. The challenge is to really decrease fat mass, increase lean mass.
Maintaining the right amount of fat and muscle involves many of the same foods a dietitian would recommend to the average person.
The major difference is that its so much more food, Ketterly said. Football players, however, do tend to eat more carbohydrates and protein. Carbohydrates provide them with energy, while protein helps to repair muscle.
For example, (for) an average person the recommended daily amount (of protein) is 0.8 gram per kilogram whereas an athlete minimum is probably going to be 1.2 grams per kilogram. In other words, the average 200-pound person needs to eat enough protein each day to equal 8 eggs, while a 200-pound football player would require closer to 12 eggs.
As a 254-pound tight end, UGA's Arthur Lynch needs to be big enough to block but also quick enough to run for passes, a set of duties that requires around 3800 to 4000 calories a day, according to Ketterly.
Lunch is definitely the most important for me, in terms of how much food I need to eat, Lynch said, referring to a typical practice day. Usually it's some sort of chicken, mashed potatoes, rice and usually a bowl of fruit or yogurt.
Players have easy access to nutrition advice while on the team, but an added challenge comes when college athletes dont move on to the pros and stop playing ball. When exercise habits change, eating habits also have to change if players want to maintain low body fat and a healthy metabolic profile.
However, its also worth noting that high BMIs specifically those in the obese range have been associated with a higher risk of death, even for people who are metabolically healthy. Athletes may have one more reason to adjust their eating and lose excess weight post-graduation, be it muscle or fat.
Ketterly hopes players continue to use some of the healthy eating tricks theyve learned while playing.
Last summer, we did an offensive versus defensive grill-off where we taught the players how to grill and gave them some food safety tips, Ketterly said. Those are skills for life that they can take forward.
To try a little football player fare yourself, check out this take on the classic chicken parm, courtesy of UGA Sports Nutrition.
4 boneless, skinless, raw chicken breasts
1 package of parmesan flavored Shake n Bake
1, 24-ounce jar of spaghetti sauce
1 cup shredded mozzarella cheese
cup grated Parmesan cheese
- Preheat oven to 400. Line a baking dish with foil. Coat with cooking spray.
- Coat chicken with Shake n Bake as directed on package.
- Bake in pan for 15-20 minutes or until chicken is done
- Top with sauce and cheese and bake 5 minutes, or until cheese is melted.
Makes 2-4 servings.