Diet Vs. Exercise: Why What You Eat Really Matters More than Working Out—And When It Doesn’t

Natasha Burton

Anne Stephneson / EyeEm/Getty

The great debate over diet vs. exercise and which is more effective has been waged for decades. So, we thought it was high time to get the real story: Is eating right the key to weight loss? Or is hitting the gym every day your best bet?

To find out, we turned to two leading fitness and nutrition experts. They say that what you eat is what really matters—here’s why.

You can’t see results without a good diet. “People say you can’t exercise off a bad diet and I believe that to be true,” says Dana Kofsky, certified nutritionist of Nutrition Styles. “If you’re not eating right for your body, then it will be very difficult to achieve the results you want.”

Registered dietitian nutritionist, exercise physiologist, and certified personal trainer Joey Gochnour, owner of Nutrition and Fitness Professional, LLC, agrees. In fact, he believes that exercise can even get in the way of achieving dieting goals. “The more you exercise, the more you have to eat to recover,” he explains. “Part of what is irritating about the personal training industry is that people will sign up for a trainer for ‘weight loss’ when you can’t really help them to achieve that goal. If that were true, [then] why don’t I lose weight when I’m active every day, even when I increase the amount I do or the intensity? If anything, I gain muscle!”

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Your body needs the right fuel to work out effectively.  If you consume too many of the wrong foods, you won’t feel as motivated or see results, Kofsky says. In fact, you may not feel like even working out and your body won’t look quite as good as it should look. “When I work with my clients, I tell them that a side effect of choosing the best foods and portions based on their body will be losing weight,” she says. “My clients who achieve the greatest results are the ones who use what they have learned in their nutrition sessions and the workouts become an added bonus to their health journey.”

But, the calories in/calories out model is stressful. The thought of going to the gym to work off what one has eaten has been around for years, and of course, Kofsky says, there is science behind the calorie in, calorie out. But, as she explains, who wants to go to the gym with such restrictions and pressures? “It is about finding a balance and learning to indulge without overindulging so you don’t feel pressure to have to work it all off at the gym,” she says. ” I teach clients to have a healthy relationship with food and avoid the ‘diet mentality’. I ask them to use exercise as a stress reliever instead, a time where they can have 30-60 minutes to themselves.” This model, in turn, will be more successful in the end – treating exercise as a supplement to your healthy diet.

Although, exercise is great for lowering body fat and maintaining weight loss. Dieting alone will cause you to lose weight, but it won’t make you stronger or have less body fat. Plus, studies show that exercising regularly is more effective in helping people keep weight off over the long-term than simply dieting by itself.

“Once you are at a good body weight for your frame size, I view purposeful exercise as most important for lowering body fat percentage by increasing lean mass,”Gochnour says. “Exercise at any body weight is considered to be preventative for many chronic diseases, and it’s great for maintaining weight loss post-diet.” So, if you are already at a healthy weight, he suggests signing up for a personal trainer for “fat loss”—that way, you can decrease your body fat percentage by increasing lean mass.