Lukas Verzbicas has a body composition of 6 percent fat and 94 percent fat-free mass. These numbers place the 2011 triathlon junior world champion well within the 99th percentile for men between the ages of 20 and 24. In other words, if you chose 100 young men at random off the street, chances are Verzbicas would have less body fat than any of them.
Linsey Corbin has a body composition of 10 percent fat and 90 percent fat-free mass. These figures rank the third-place finisher of the 2011 Ironman 70.3 World Championship inside the 99th percentile for women between the ages of 30 and 34. (Women naturally carry a little more fat on their bodies than men do.)
Compared to other championship-caliber triathletes, however, Verzbicas and Corbin are about average in terms of body composition. This is no great shock because research has shown that body-fat percentage is a powerful predictor of triathlon performance. The leanest triathletes tend to lead the pack, while those with a little more fat follow close behind, and so on. In fact, some studies suggest that body-fat percentage affects triathlon performance as strongly as VO2max (or aerobic capacity) does.
It’s not hard to understand why. Although a certain amount of body fat is needed for good health, any extra body fat is dead weight that increases the energy cost of running and of accelerating and climbing on a bike. It also reduces heat dissipation, compromises muscle fueling, and slows athletes down in other ways.
Body composition is influenced by genetic makeup. Few people are born with the physical capacity to healthily become as lean as the likes of Lukas Verzbicas and Linsey Corbin, just as few people are born with the potential to attain a VO2max as high as theirs. But even the most gifted triathletes cannot rely on favorable genes alone to get lean enough to contend for world championship titles. They must rely on hard training and, yes, careful eating as well.
There are many noteworthy examples of gifted triathletes who became leaner and performed better after cleaning up their diet. One such example is four-time Olympian Hunter Kemper. Through the first several years of his professional career, Kemper was a somewhat careless eater with a weakness for Krispy Kreme donuts. But after the 2004 season he decided to make a change. He met with a sports nutritionist and subsequently improved his diet by adding vegetables and other high-quality foods and by subtracting donuts and other sweets. He lost excess body fat that he hadn’t even known was there and finished the 2005 season as the ITU World Cup champion.
The sport of triathlon is so competitive that no athlete is talented enough to reach the top with poor training or eating habits. So the training methods and dietary patterns that are most widely shared among the world’s best triathletes are almost by definition those that work best. In researching my book, Racing Weight, I studied the eating habits of elite triathletes and other world-class endurance athletes with the hope of identifying a diet formula that other athletes could use to reach their own ideal body composition for racing performance. The results of this research were both surprising and encouraging.
Age-group triathletes who decide to get serious about shedding body fat often follow a “diet with a name.” Examples include veganism, the Paleo Diet, gluten-free diets and the Zone Diet. These and other named diets are typically defined by rigid restrictions that are out of step with both normal cultural eating habits and mainstream nutrition science guidelines. For example, the Paleo Diet forbids the consumption of all grains, whereas grains are a major component of every major cultural diet—and nutrition science has clearly demonstrated that people who eat lots of whole grains are healthier than people who eat few.
By contrast, elite endurance athletes, as I discovered, generally practice what I call “agnostic healthy eating.” With rare exceptions, they do not follow diets with names. Instead they eat like normal people, without rigid restrictions. But the pros do eat very carefully, packing their meals and snacks with high-quality foods that are proven to prevent long-term weight gain (specifically vegetables, fruits, nuts and seeds, lean meats and fish, whole grains, and dairy) and limiting their consumption of low-quality foods that are known to promote weight gain (specifically refined grains, fatty meats, sweets and fried foods).
What’s great about agnostic healthy eating is that it is a more flexible and accommodating approach to eating than are the diets with names, yet it is no less effective. Agnostic healthy eating is far from an “anything goes” approach to feeding yourself, but it is relatively easy to sustain because it does not require you to give up favorite food types forever or aim for a precise macronutrient ratio or anything like that.
In Racing Weight I formalized the agnostic healthy diet that I observed in the world’s best endurance athletes through a set of guidelines that make the approach simple to emulate and easy to adapt to any athlete’s personal eating preferences. These guidelines are summarized in the table to the left.
The book also includes many examples of agnostic healthy eating in practice that are included. I’m sharing one on the next page: a one-day food journal from now-retired pro triathlete Chrissie Wellington. Notice that it includes many of the high-quality food types and even a low-quality treat. Despite its normalness this diet was good enough to keep Wellington lean and fast, and I am certain that an agnostic healthy diet of your own will help you attain your optimal racing weight.