Limit Your Calorie Intake

Losing weight boils down to simple math. To lose one pound weekly, burn or cut out 3,500 calories in the course of seven days. That breaks down to 500 calories per day. It's difficult to cut out that many by dieting alone, especially for someone who loves to eat. The most effective approach is this combo: each day, cut out 250 calories from your diet and burn 250 through exercise. Choose to either cut out one 250-calorie item such as a serving of ice cream, or omit a few small things that add up to 250 calories a day.
It's also important not to exceed your recommended daily calorie intake. Check out this calorie calculator to figure out how many calories to consume each day, based on your current weight and your weight-loss goal. Don't dip below 1,200 calories to prevent going into starvation mode, which makes your body hold onto the weight.

The Definitive Guide to Losing Weight