A new study out of the University of California-Los Angeles suggests that eating a consistent diet of processed foods and carrying extra weight causes people to become tired and inactive—not the other way around. But on the upside, it indicates that a few processed food binges isn’t enough to impair our motivation.
Researchers fed 32 rats two different diets—one a normal diet of foods like ground corn and fish meal, the other a processed diet with ingredients like corn starch, sucrose, and soybean oil. After three months, the rats on the processed diet had grown obese; they also took much longer breaks during tasks than the leaner rats.
After six months, the rats switched diets for nine days. The obese rats’ weight and responses to tasks didn’t improve, but the leaner rats’ weight stayed about the same, and their responses to the tasks weren’t impaired.
Though the study was performed with rats, lead researcher Aaron Blaisdell says it’s very likely the results apply to humans, as we share some of the same neurophysiological and hormonal mechanisms.
“Humans who are obese likely suffer from impairments in motivation, either driven by a reduced capacity to be motivated by rewards, or by higher amounts of fatigue and lethargy, or both,” he says. “Thus, once an individual becomes obese through lifestyle factors (e.g., poor diet), then it creates a situation where it is more difficult to exert effort to reduce the obesity.”
But the fact that the leaner rats didn’t suffer after nine days on the processed food diet also indicates that a few processed food binges aren’t likely to cause immediate lethargy and motivation problems. Unfortunately, though, it’s also unlikely that a short period of clean eating will erase the damage from regular junk food consumption.
“It might take more than a few days to a week of eating a clean diet to reduce the motivational impairments induced by the previous chronic consumption of a junk food diet,” Blaisdell says.
After that long, strenuous workout, nothing sounds more appealing or more deserved than some tasty treat, right? Wrong. Very wrong. Runners need to think twice before consuming calories that are going to burn their health in the long run.
“It’s easy to pick up a pastry or cookie after burning a thousand calories because it’s fun, you worked hard, and you want to enjoy something,” says Nancy Clark, a registered dietitian with a board certification in sports nutrition. “But being a lean runner doesn’t mean you can eat eight cookies—you have to dose the poison.”
When you don’t, the results can be scary—even if you’re skinny. A recent study published in Missouri Medicine pegged marathon training to increased coronary plaque, likely caused by the dietary indifference of many runners. Every calorie isn’t created equal, when it comes to your health or to performance.
Until 2007, Olympic steeplechaser Anthony Famiglietti flat-out bragged about his junky diet that consisted of sweets, fast food, and nary a fruit or vegetable. But that year, when his body broke down and he couldn’t run a single mile without a walking break, he knew his diet needed a reality check. “You have to treat your body like the vehicle it is—like a car,” explains Clark. “You put the right type of fuel in your car before you drive it, so put the right type of fuel in your body before activity.” After replacing the stromboli with broccoli, Famiglietti found himself at the Olympic Trials running his fastest, and then posting a personal record in the Games.
But for all the press the Missouri Medicine article has received, healthy eaters can have issues too. When Amby Burfoot, editor at large of Runner’s World and a marathoner, found himself in the doctor’s office with sky-high coronary calcium numbers, the 45-plus-year vegetarian was shocked. “I’d always considered my health and my diet better than most people’s,” says Burfoot. “But with all the recent news about excess artery plaque in marathon runners, I wanted to check things out.” So how do runners approach what they put into their bodies and what they get out of it?
The answer is not clear-cut. But we do know—despite exceptions like Burfoot—that diets filled with fruits and vegetables and low on processed foods have been linked with the best health outcomes. The problem, then, is our desire to look for perfect solutions (while ignoring the fundamentals) and our unwillingness to stick with the pro-vegetable plan long-term.
Which is where the daily cheat comes in. Clark contends that up to 10 percent of your daily calories can come from foods like cookies. The theory is that if one cookie can help you eat that bowl of salad, it’s worth the sugar. That said, your cheat foods don’t always have to go toward that 10 percent buffer.
“People want yummy food,” says Clark. “But yummy food does not have to be bad food.” When rewarding yourself, she recommends that you focus on what really tastes good, instead of automatically reaching for artificially flavored and processed products. “Fix yourself a breakfast of French toast and eggs, or have a few spoonfuls peanut butter,” Clark suggests.
Running is hard work, and if you can’t earn the right to eat this stuff in the middle of marathon training, then when can you?
If we were to tell you that studies now show that running anything beyond 20 miles a week could kill you, you’d cut back from your 50-, 60-, 80-mile-a-week habit straightaway, right? Yeah. Sure you would.
For years, athletes, particularly those of you known to scientists as EEs (Extreme or Endurance Exercisers)—marathoners, ultrarunners, triathletes—have tended to eat whatever you damn well please, under the assumption that all calories being more or less equal, if you’re burning 3,500 a day, you can have that bacon double cheeseburger and the vanilla shake no problemo. Turns out, not only has that been magical thinking dietetically, but even more disheartening, all those extra miles may have been doing you more harm than good—if your only goal is to live as long a life as possible.
And it may not even have everything to do with what you’re eating or how much. (Though it certainly has an effect.) The issue may be in how hard you’re pushing yourself. “People on the far level of exertion may be putting themselves at risk for mortality,” says Dr. Paul D. Thompson, an 11-time Boston Marathon finisher and director of cardiology at Connecticut’s Hartford Hospital.
What got lost in all the hype over last month’s Wall Street Journal story, “Why Runners Can’t Eat Whatever They Want,” was the real issue buried inside it: that the atherosclerotic risk EEs may be subjecting themselves to has less to do with diet and more to do with what they’re overdoing. The theory is, says Dr. Thompson, “If something’s good for you, more is better. So, the more exercise, the less heart disease.” Well, everybody’s susceptible—no matter how much you exercise.
Like an ultramarathoner’s gonna cut back on their mileage. Then again, maybe they should—if longevity is their primary concern (it isn’t). Picking up on Ralph Paffenbarger’s landmark Harvard Alumni Health Study, which took a longitudinal look at the exercise routines and rates of cardiovascular disease of 17,000 Harvard alum, other researchers have shown that “the benefit of exercise becomes less and less as you exercise more,” says Dr. Thompson. “To the point where there may be no benefit at all.
What’s misleading about the Missouri Medicine study cited in the WSJ, wherein researchers found that 50 men who had run at least one marathon a year for 25 years had higher levels of coronary-artery plaque than a control group of sedentary men, was that these EEs likely “had, for one, a very unhealthy diet,” says Dr. Aaron Baggish, associate director for the Cardiovascular Performance Program at Boston’s Massachusetts General Hospital. “They also led an unhealthy life in their 20s and 30s. And they were at high risk for hereditary heart disease before they even started running.”
As contradictory as that may appear—which is worse, eating whatever you want because you exercise all you want, or simply exercising all you want?—it’s likely evidence for conducting a study on EEs who have no significant cardio issues prior to late-age exercising and who’ve always eaten a balanced diet.
And lost in all the schadenfreude among the sedentary, who finally got to thumb their noses at the EEs, is that, while exercise is good for you (and way better than sitting on your ass and praising yourself for it), “Marathon running puts extreme stress on the body,” says Dr. David Katz, director of Yale University’s Yale-Griffin Prevention Research Center. “That’s exercising too much.”
“The difference between running 75 miles a week and 100 is not that significant,” adds Dr. Thompson. “When you go out to these extreme levels of health, you’re doing it for something other than just exercise.”
Which, for many an EE, is exactly the point.
“The take-home message is that exercise is good for you,” says Dr. Thompson, who adds that another ongoing study of Tour de France riders shows that they’re living longer and seemingly without much damage to their hearts. “It could be there’s less benefit once you get over some threshold. We just don’t know yet what that threshold is.”