Celebrity followers
Courtney Cox Arquette

The theory
This is the opposite of a high-carbohydrate, low-fat meal plan. It emphasizes more protein and fat and less reliance on carbohydrates to stimulate weight loss.

The plan
There are numerous variations of the high protein diet, but all recommend that you get 30 to 40 per cent of your calories from protein (against a typical average of 15-18 per cent). Foods that are high in carbohydrates - especially sugars, pastas, breads, cereals and potatoes - are limited, but not banned. A typical diet in this caterogy is The Zone, but it is the fact that carbs are restricted rather than more-or-less cut out that differentiate it from very low-carb diets like Atkins.

Pros

• Protein in foods can satisfy our appetite, and favourite high protein foods such as steaks and hamburgers may be enjoyed guilt-free. Lower-carbohydrate vegetables like salad greens, carrots, tomatoes and broccoli are encouraged.

Cons

• Some high protein plans restrict carbohydrates too severely to be healthy. Excessive consumption of protein can be harmful, as it can overwork the kidneys. The elimination of many bread and cereal products can decrease fibre in the diet, and limit your consumption of many essential vitamins and phytochemicals.


• You tend to consume a lot of fat on this diet, which may promote heart disease and some types of cancer.

Duration
Indefinite.

The pros say
Some people will benefit from increasing the protein in their diet, but this plan can be unbalanced if not carefully thought out. By focusing primarily on protein, you may not get other important nutrients, such as fibre, that you would get if you were eating a variety of foods, unless you take care to eat sufficient pulses and vegetables.