Founded by Dr. Barry Sears, The Zone Diet focuses on maintaining an ideal weight by controlling insulin and other hormone levels. The Zone dictates that the dieter's meal plate be divided into three equal sections. One-third of the plate should contain a low-fat protein that's no larger or thicker than the palm of your hand. The other two-thirds of the plate should overflow with fruits and vegetables. The diet allows a dash of heart-healthy fat, such as olive oil, guacamole and hummus. (Unlike animal fats, heart-healthy fats raise your good cholesterol and reduce your bad cholesterol.) Pasta, bread and other starches like white potatoes are strictly limited, as these foods can send insulin levels skyrocketing and send you out of "the Zone."

Diet Fundamentals:

• Three meals, plus two snacks per day
• Meals should be one-third low-fat protein and two-thirds fruits and vegetables
• Strict portion control
• Good carbs (whole grains) over bad carbs (white bread, potatoes)
• Lots of fruits and vegetables
• Moderate portions of alcohol and dessert

Sample menu:

Breakfast
• Breakfast burrito (a low-fat tortilla with egg whites, low-fat cheese, and salsa)
• 1 cup of strawberries

Lunch
• Half a pita with a palm-sized portion of lean protein, a small amount of mayo and vegetables.
• 1 small apple

Afternoon Snack
• 1 cup of low-sugar yogurt with chopped nuts or blueberries

Dinner
• Chicken or shrimp stir fry, with a palm-sized portion of low-fat protein and a lot of vegetables
• 2 teaspoons olive or canola oil

Dessert
• Low-fat dessert, fruit or a moderate amount alcohol

Pros and Cons:

The Pros
• The Zone doesn't completely exclude any major food groups.
• Heart-healthy omega-3 fatty acids will help the dieter's cholesterol profile.
• The diet leads to weight loss and energy gain via insulin control.
• Dieters can reduce their risk of heart disease and diabetes by sticking to The Zone.

The Cons
• The Zone requires disciplined portion control.
• Dieters may find it difficult to keep the kitchen stocked with fresh fruits and vegetables.
• Inflexibility makes The Zone hard to stick to when eating out or vacationing.
• Dieters may find the rules of The Zone too complicated to follow.