The Zone diet, made popular by celebrities such as Jennifer Aniston of Friends, was created by biochemist Barry Sears. This program is another of the popular diets based on the theory that eating too many carbohydrates makes the body produce excess insulin which, in turn, causes your body to store fat. However, excess insulin is not caused by eating too many carbohydrates but by being overweight, which is a result of consuming too many calories and doing little physical activity.

Sears recommends that at every meal the ratio of calories from carbohydrates, protein and fat should be 40% carbs, 30% protein and 30% fat. Recently, to make the diet more palatable, Sears has said that the distribution of foods doesn't have to be in that precise ratio.

What do you eat on this plan?
This diet recommends getting most of your carbohydrates from fruits and vegetables, including low-fat protein and dairy foods and keeping an eye on portion sizes – all of which are helpful if you want to lose weight. Overall, the main reason that you will lose weight on this diet is that you will be reducing calories - the best, tried and tested method of weight loss.

What's the verdict?
Including the right ratios of carbs, fats and protein in your diet at every meal can be an exhausting task. It requires much planning, organization and calculation which may make this diet very hard to stick to. Also keep in mind that reducing carbohydrates may mean that you are missing out on important sources of fiber and energy.

The Calorie King says: The basis of the diet is good, but it's too tough to stick to for the long term.