I built my first treadmill desk in October 2006. Since then I’ve taken countless steps and have seldom missed a day of walking while working.

Yet I still managed to eat my way up to 222.5 pounds. My friend Marina was like, “You walk all the time, how can you gain weight?”

Easy. It’s the exact same way everybody gains weight – when caloric intake exceeds caloric output. Yes, you ate too much.

A pound is 3,500 calories. It goes on a lot quicker than it comes off. It takes less than a minute to eat a plain doughnut but you have to walk over an hour to burn it off. Want a big slice of pizza? That’s another couple hours. Add an ice cream cone. Now you’re talking over 4 hours to work it all off. And that was barely one meal.

The math is inescapable. There’s not enough exercise in the world to overcome the damage your mouth can do in just a few minutes.

You cannot out exercise a bad diet, no matter how fast you run or how many reps you do. (And remember, diet is what you eat and drink, not something you start and stop.)

If you’re trying to lose weight in a healthy way, be aware and understand what you are consuming. At the end of the day it’s about calories in vs. calories out. Always has been, always will be, whether they’re disguised as points, exchanges, whatever. Good ole calories.

Yes, exercise is important and makes it much easier to lose weight and get toned. But too often people overemphasize exercise and undervalue the importance of eating healthy.

For optimum results, the best exercise is to close your mouth when you’re full and move your body as much as possible while eating healthy most of the time. Maintain a caloric deficit and you can’t help but lose weight. It’s a mathematical certainty!