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Why You Can't Out-Run a Bad Diet


When I signed up to do my first marathon many years ago I had a few thoughts. One was, "OMG, WTF am I doing?" And the second was, "I can eat anything I want—YAS!" Embarrassing as that is, I bet I'm not the first person to have that mindset. And while digging into endless pints of ice cream and being a regular at my favorite bar's 25-cent beer and wing night did not cause the pounds to pack on as quickly as they would have if I had been sedentary, I realized when I crossed that finish line and started my recovery for the next few days that diet does indeed make a big, big difference.

Even if you're not running marathons, chances are you've had a stare-down with a cookie or two in your lifetime and have thought to yourself, "What the heck, I'll just work out more later." And while you definitely should treat yourself sometimes, it's important to remember that as a general rule you just can't out-exercise a bad diet. "There is an overwhelming belief that all bad eating can somehow be rectified by lots of sweating," says Kimberly Gomer, MS, RD, LDN, nutrition director at the Pritikin Longevity Center + Spa. "Unfortunately many people overestimate how many calories they burn through exercise and underestimate how many calories they eat. Much of the gym equipment we use contributes to a false sense of calories burned, and denial contributes to thinking we eat much less than we actually do." Add that to portion sizes, which seem to be constantly out of whack, and it's a wonder we're even able to guesstimate our daily calorie intake.

And that doesn't mean the solution is to cut back on the good stuff so we can have more of the bad while still staying fit. "You need to perceive food as fuel," says Christie Cash, co-founder and chief ambassador at BikiniBOD. "Great nutrition affects every aspect of your life: mood, sleep, and your appearance. Allowing your body to have the right nutrients it needs is critical no matter what type of activity." Gomer agrees: "A healthy diet is like putting premium fuel in your gas tank. A junk food diet is just putting sugar (literally) in your tank. We need food to feel energetic and fuel our workouts as well as help recover post-workout. Cash lives by the acronym C.P.F.—good carbs (like green veggies, yams, etc.), protein, and good fats (avocado, nuts, etc.). She recommends a 40-30-30 ratio for females. If your C.P.F. ratios are off—for example if you skimp out on the carbs—you'll feel sluggish, which will impact your performance."

As for that marathon, Gomer assures me I am not the first genius to have these thoughts. "You can go to a marathon and see those folks lined up who have trained to run 26.2 miles—that's a lot of running. But many of them are overweight because they out-eat their training, which isn't hard to do. Plus, they feel physically and psychologically able to overeat because they think to themselves how hard they've worked out." Gomer's equation is all about balance. Combining cardio (and not overdoing it) with strength training (which helps your muscles speed up your metabolic rate) along with a healthy diet will make it easier to reach and maintain your weight-loss goals.

This little equation proves true when I'm crazy enough to sign up for my second marathon just a year after my first. A little more lifting, a little more noshing on veggies, and a lot less gorging on wings—and I have the 10-minute PR to prove it.