Those who do not find time for exercise now will have to find time for illness.
--The Earl of Derby, 1873
Don't kid yourself into thinking that exercise, by itself, will make you lose weight. Consider the following activities, and the number of calories an average person burns per hour in each.
Compare those numbers, remembering that they're for a full hour spent nonstop in the exercise, with the calories in the following food items:
|Peanut butter sandwich||275|
|Pizza (3 slices)||500|
Clearly, even an hour a day of exercise doesn't account for much food. And what's the likelihood you'll find the time to spend a full hour, every day, month after month, year after year, doing those exercises?
So, don't exercise to try to burn off calories and lose weight. Unless you're a professional athlete or obsessed with sports, you're not likely to spend enough time exercising strenuously enough to make much of a difference. Exercise will help you lose weight in more subtle ways. Regular exercise increases your rate of metabolism: the number of calories you burn all the time. Plus, for many people, exercise actually reduces appetite.
But these are side effects: hardly reasons to start exercising. The real reasons to exercise are that you'll live longer and feel better. Let's consider the case for exercise from those standpoints.