What to look for

Fibre

Per 100g look for more than 5g (no more than 15g for children).

Adults should eat 25-30g of fibre a day. Cereal grains can be high in fibre, so you should be able to rely on the cereal you choose to provide a fair whack of your daily needs.

There are two types of dietary fibre - soluble and insoluble - and both are important in a healthy diet. Soluble fibre (found in oats, fruit and barley) can help prevent constipation. Insoluble fibre (found in whole wheat and wheat bran) adds bulk to your diet and speeds everything through your system.

Bran-based cereals are high-fibre options. Kellogg's All-Bran and Nature's Path Organic Optimum Power both have more than 20 percent fibre. Wheat biscuits, porridge and some mueslis and light flake cereals are also good choices.

Regular cornflakes and puffed rice are low in fibre - although some of these products now have added psyllium to boost their soluble fibre content.

Fibre is important in assessing a good cereal. Although it's not mandatory to list fibre, we think all manufacturers should. If they did, more cereals would probably get our seal of approval.

Sugar

Per 100g look for less than 15g (25g is acceptable if some of the sugar comes from fruit).

Cereal grains contain little sugar. But breakfast cereals often have sucrose, glucose or honey added. These add energy without adding nutrients. Sugar also causes tooth decay.

In some cases it's obvious. Anything with "honey" in the title will be high in sugar. With others you need to check the ingredients list. For example Kellogg's Crunchy Nut Corn Flakes contain more than 30 percent sugar.

Dried fruit adds to the sugar content. And because bits can get stuck in your teeth, they can be even worse for tooth decay. But dried fruit contains fibre and other nutrients - so we've allowed a sugar content of up to 25 percent if some of the sugar comes from fruit.

Wheat biscuits and porridge are good low-sugar choices. But watch the amount of sugar you sprinkle on top! Use fruit or flavoured yoghurt to add sweetness.

Tip: If sugar (or one of its many aliases) is listed in the first few ingredients, put it back on the shelf.

Fat

Per 100g look for less than 5g total fat (10g is acceptable if saturated fat is less than 2g).

There's not a lot of fat in most cereals. Muesli is the main culprit - ingredients are often baked in oil to make them crunchy or include other high-fat ingredients like nuts and seeds.

However, nuts and seeds have mainly unsaturated or "good" fats and provide other nutrients. The exception is coconut: it's high in saturated fat.

Grain Foods Toasted Muesli is the worst fat offender. It has more than 20 percent fat, nearly half of which is saturated fat. The ingredients list on Hubbards Caramel Cashew Crunch Muesli reads more like a dessert: this high-fat cereal should be kept for treats.

Sodium

Per 100g look for less than 400mg.

This is the baddie in salt and is linked to high blood pressure - a key risk factor in stroke and heart disease. It's added to some cereals during processing.

Some brands of cornflakes and bran cereals are high in sodium.

What about kids?

In October 2008 we looked at cereals marketed specifically to kids. Generally speaking, good choices for kids are the same as for adults - but steer clear of the very high fibre options (more than 15g per 100g). Children shouldn't eat lots of fibre because it can make a small stomach feel full before the child has got the nutrients it needs. It can also cause small children to have stomach upsets and diarrhoea.