I'll just exercise to lose weight...

ummmm... no, I'm sorry, but I don't think you will. Before you react, tell me: how many people do you know who:

1. went on a weight loss program, and
2. reached their goal or target weight, and
3. did so primarily or exclusively through exercise?

Exercise is vitally important, for numerous reasons. Of course! :) Walk, dance, go for a bike ride, mow the lawn, play with the kids, swim, clean the garage, make love (not in that order!) Just get moving! It's good for you, and the right exercise can be a lot of fun! But exercising your way skinny? It won't happen. Not for normal folks who have a life outside the gym or exercise track.

Weight loss is "simple" science: consume less energy (fewer calories) than you burn each day, and you will lose weight. We all use energy / burn calories even while sleeping. Breathing, pumping blood, digesting food, rolling over -- all burn energy. Increase your energy usage (burn more calories) without increasing your energy intake (consuming additional calories), and you will lose weight.

If exercise = increasing your energy usage = burning more calories, why can't you exercise your way skinny?

A physician recently told me that the average person would need to exercise vigorously for at least 90 minutes per day in order to experience a significant weight loss. Do you have that much time to dedicate to exercise? Every day?

According to the Centers for Disease Control (CDC), a "180-pound man riding 10 miles will burn 400 calories, and a 130-pound woman riding the same distance will burn 300 calories." That would be a very good thing, and most of us could probably benefit by increasing the amount we exercise.

The CDC also informs us "To lose weight, you must use up more calories than you take in. Since one pound equals 3,500 calories, you need to reduce your caloric intake by 500—1000 calories per day to lose about 1 to 2 pounds per week."

Our 10 mile a day bike riders are only burning 300-400 calories per day, not the 500+ required to burn a pound or more per week. Here's the math: a 180 pound man burns 400 calories per day / 2,800 calories per week if he bikes 10 miles every day. If he doesn't also reduce his energy intake by consuming fewer calories, he's still not burning enough calories/week to stop gaining weight.

"I'll just exercise to lose weight"? Sorry, but I don't think you will.