Protein, fruit and vegetables

Protein

The current Food Pyramid puts all proteins in the middle. The Harvard version separates them into red meat at the top, and other protein sources which it places further down.

Red meat can be high in saturated fat, which is why Willett puts it at the top. But some cuts of meat are far fattier than others, and these are the ones to avoid. Neither pyramid reflects this.

Processed meats, like salami, sausages and bacon, are also high in saturated fats, while lean red meat is an important source of iron.

Fish and shellfish are healthy protein sources. They have little saturated fat, and if the fish is oily, like salmon or sardines, it will be rich in omega 3. Everyone agrees this increases the heart-healthy benefits.

Chicken has a thick layer of fat in and just under the skin, and you'll also find lumps of fat clinging to various parts of the body. Get rid of these, and it's generally agreed chicken is a healthy source of protein.

Nut oils are unsaturated, and therefore in the "good fat" category. But since they are high in fat, the prevailing view is to eat them sparingly. Willett says nuts, along with other plant proteins like soy and beans, should be eaten in up to three servings a day. (Note that he is not talking about salted nuts or nuts cooked in animal fats!)

Nuts, like most other protein sources, are more filling than other foods, which is probably why high-protein diets are known to lead to short-term weight loss (see What about Atkins and the Zone?).

There are several useful messages to draw from all this. First, choose a variety of lean meat and poultry. Second, substitute fish, nuts and other plant proteins as often as you can.

Third, limit the size of your portions. Nutritionists agree that protein, whatever its source, should not form the bulk of your meals.

Fruit and vegetables

Eating lots of fruit and vegetables is not controversial. Fruit and veges are the main source of many of the vitamins, minerals and fibre needed for good health. They are also a significant source of antioxidants.

And because they are low in kilojoules they're good to fill up on.