Both training and diet contribute toward the attainment of a runner’s optimal racing weight during the process of preparing for a marathon or half marathon. As I will explain in Chapter 9, the right approach to training will burn excess fat off your body in addition to building fitness. But smart training alone won’t reduce your weight to the optimal level for racing. To get all the way there you must eat right, too. In fact, runners generally have to eat more carefully to reach their optimal racing weight than must nonrunners to reach a “merely” healthy body weight. One of the reasons is, again, that a runner’s optimal racing weight is in most cases significantly lower than the upper limit of his or her healthy body weight range. A second reason has to do with a phenomenon called the compensation effect.
The compensation effect is the tendency of individuals to eat more when they exercise more. Appetite is linked to activity level. Men and especially women often lose less weight than they expect to lose through increases in exercise because they become hungrier and eat more. Runners are not exempt from the compensation effect, which has been known to cause some runners to actually gain weight while training for a marathon or half marathon despite burning many more calories than they do at other times. To overcome the compensation effect and reach your optimal racing weight you may have to make even better dietary choices than you do at other times.
It’s true that some runners with favorable genes (who are known as exercise responders) lose a little weight “automatically” as they increase their training in preparation for a marathon or half marathon, even if their diet leaves something to be desired. Too often these runners interpret any amount of training-induced weight loss as proof that they are doing enough to manage their weight for running performance and can get away with continuing to eat somewhat carelessly. Indeed, the competitive running culture has traditionally taken a certain amount of pride in the apparent power of high-mileage training to overcome any potential negative effects of unhealthy eating habits. In his classic 1978 novel Once a Runner, John L. Parker Jr. wrote, “If the furnace is hot enough, anything burns, even Big Macs.” That phrase—“If the furnace is hot enough, anything burns”—has remained a slogan of junk-eating competitive runners ever since.
Those runners who are naturally lean and/or who maintain particularly high training loads are the ones who are most easily fooled into believing that they can eat a sloppy diet without suffering any consequences. After all, when they look in the mirror they don’t see any extra fat on their body. Bill Rodgers famously filled his belly with gallons of mayonnaise, buckets of sugary breakfast cereals, chocolate chip cookies, snack chips, soft drinks, and gin and tonics. Rodgers’s eight career victories in the Boston and the New York City marathons might seem to prove that his diet did not hurt him. But it’s possible—even likely, I think—that with a better diet Bill Rodgers would have become even leaner than he was and run even faster than he did.
There are noteworthy examples of elite runners who had questionable eating habits before taking a leap of faith and cleaning up their diet. The results of these individual experiments suggest that no runner truly gets away with loose nutritional standards. One such case is that of Chris Solinsky, who despite eating a couple of frozen pizzas every week while running for the University of Wisconsin won five individual NCAA titles. With that kind of success Solinsky had as much reason as any runner to believe that his diet wasn’t holding him back one bit. But at 165 pounds he was heavy for a runner of his caliber, and his consciousness of this fact perhaps made him a little more open to experimenting with stricter nutritional standards than 128-pound Bill Rodgers ever was. After turning professional and moving to Portland, Oregon, to run for Nike, Solinsky cut out the frozen pizzas, started cooking for himself more, and increased his fruit and vegetable intake. Sure enough, he lost a few pounds and took a quantum leap forward as a runner, setting an American record of 26:59 for 10,000 meters in 2010.
Chris Solinsky was running between 100 and 120 miles per week when he set his record. If a runner like him cannot reach his optimal racing weight without eating carefully, then no runner can. This hard reality is much more widely accepted among today’s elite runners than it was among runners of Bill Rodgers’s generation. Solinsky represents a new breed of runners who understand that any runner who takes his diet as seriously as he takes his training will be leaner and race better than a runner who considers hard training a license to eat whatever he wants. Whatever your goals, whether you’re a lifelong runner like Solinsky or a weekend warrior, or you’re training for a longer race for the first time, paying attention to your weight and running at your leanest will help you avoid hitting the wall.
There are right ways and wrong ways to pursue weight loss as a runner. The usual dieter’s approach of sharply reducing overall food intake is the wrong way. The problem for runners is that this approach deprives the body of the fuel it needs for training and recovery. It also exacerbates the compensation effect. If training hard makes a runner hungry, then training hard and eating less makes a runner intolerably hungry. To shed excess body fat while training for a marathon or half marathon without underfueling your body and driving yourself crazy with hunger, you cannot eat less. Instead you must follow the example of today’s world-class runners such as Chris Solinsky and simply eat better. In other words, you need to focus more on the quality than on the quantity of the foods you eat.