Nutrition vs. Exercise: What Matters More?

It's one of the biggest cliches in the fitness world.

We've all heard or read it: The majority of your fitness happens in the kitchen, not the gym. Depending on who you believe, nutrition accounts for two-thirds, three-quarters or even 80 percent of the equation. But I don't think it's as simple as that.

If you've been reading the blog for a while, you know that I'm a big believer in Calories In, Calories Out. Humans are not exempt from the First Law of Thermodynamics. It's pretty simple: If you burn more calories than you consume, you will lose weight. You can alter either side of that equation -- Calories In or Calories Out. So why do so many people insist that diet has so much more impact than activity does?

The reasoning goes something like this: Most people can find more excess calories in their average daily intake than they can burn off. I'm painting with a really broad brush here, but in a reasonably intense cardio session, you can expect to burn about 10 calories per minute. So if you can devote 45 minutes to your workout four times a week, you can burn about 1800 calories -- more or less the amount it'd take you to lose half a pound. Whereas if you're eating 4000 calories a day, you can cut 1500 or more and still get all the macro- and micro-nutrients you need, and you can do it seven days a week. That's 10,500 a week, or 3 pounds.

So that's it, right? Case closed. Diet is way more important than exercise.

I say no.

Exercise Helps Keep Your Metabolism Going. As you lose weight, your metabolism will drop. This is basic science: The less of you there is, the less fuel it takes to keep you alive. One pound of muscle burns 6 calories a day; one pound of fat, 2. If you lose 10 pounds of fat, your body will actually burn 20 calories less per day. But if you lose 20 pounds of fat and gain 10 pounds of muscle, you'll burn 20 more calories per day. A huge difference? No. But it is an extra 2 pounds per year.

Exercise Keeps You Healthier. Yes, losing weight through diet lowers your risk of obesity-related diseases such as hypertension and diabetes. But it doesn't actually strengthen your heart. Exercise can also strengthen your bones, reduce the risk of some cancers and improve your mental health. It can even help stave off dementia. Simply cutting calories can't do any of that.

Lean Bodies Look Better. Let's face it: A big motivation for most Regular Guys is the desire to look a little better. Sure, you can focus on diet and get lean, but really, you'll just be skinny. A little bit of muscle definition -- we're not talking Schwarzenegger -- is the difference between the skinny guy and the trim, healthy-looking guy. Go ahead, ask your wife.

You're Going to Plateau. How much weight have you gained in the past year? If you've held relatively steady for a while, that means you're already at equilibrium -- you're taking in the same amount of calories you're expending. Now, an obese guy might hit that point at 3000 calories or more a day, even without any significant activity. But for most of us, that point is 2500 or less. And I have news for you: You are not going to be happy, long term, cutting any significant amount from that number. So the obvious solution is to ramp up your Calories Out. Still don't believe me? Recent research shows that physical activity has a higher correlation with healthy weight than diet does.

You'll never get this feeling of accomplishment by dieting!

Working Out Is More Fun Than Dieting. Regular Guys, dieting sucks. You're hungry, you're irritable, there's tons of stuff you "can't" eat, and worst of all, it's not sustainable. A better plan is to find an activity you enjoy and use solid nutrition to fuel yourself. Football star J.J. Watt eats 9000 calories a day -- does he look fat to you?


Now don't get me wrong. I'm not advocating the "see-food diet." Even if you're working your ass off, you can burn only so many calories. You still have to balance the CICO equation. And the best way to do that, of course, is with a diet that's heavy on nutrient-dense foods.

But for my money, the bigger factor is exercise. So get to it!

A quick note: There are some folks for whom this isn't good advice. Someone who's morbidly obese will put himself at significant risk by jumping into an intense exercise program. Other people have health conditions -- such as COPD or heart disease -- that should preclude them from intense exercise as well. And, of course, if you're suffering from a long-term or permanent injury, you need to be sure you won't do further damage through your exercise program. If any of these is you, talk to your doctor about fashioning a diet-and-activity plan that will work for you.