All you need to know There can't be many people around who haven't heard the five-a-day health message. Yes, we all know we should be eating five portions of fruit and veg a day - yet research has shown that most of us actually eat fewer than three. Just why is it so important we up our intake? And how can we get into the five-a-day habit? Why we should go for five Fruit and vegetables are vital for a healthy lifestyle because they contain essential vitamins and minerals, which our bodies need to function properly. For example, vitamin C helps maintain healthy skin, gums and nerves, while calcium helps support healthy bones and teeth. Fruit and veg also contain healthy fibre and antioxidants, which help mop up free radicals. These are the toxic by-products of the body's metabolic processes, and they can cause damage that leads to disease and ageing - but the good news is that antioxidants found in fruit and veg can help make these harmless. According to the Department of Health, increasing the amount of fruit and veg you eat is the second most important thing you can do to reduce your risk of cancer, after stopping smoking. For optimum health benefits, you should vary your five a day as much as possible. Why? Because different coloured fruits and vegetables contain different combinations of nutrients. So oranges are high in vitamin C, while asparagus is high in folic acid. Is it just fresh produce that counts? No - frozen, canned and dried versions count, too. Do potatoes count? No, they don't. Although they are vegetables, the main nutrient in potatoes is carbohydrate (starch). We eat potatoes in place of other sources of carbohydrate/starch, such as rice, pasta or bread, so this is why they don't count towards our five a day. Other root vegetables, such as parsnips, swedes and turnips, are usually eaten as well as the main starchy food in a meal, so they do count. As do sweet potatoes, which provide starch, but are also rich in vitamins A, C and E. What about beans and pulses? Yes, they count, but they can only be counted once, no matter how many portions you eat. This is because although they contain fibre, they don't provide the same mixture of vitamins, minerals and other nutrients as fruit and vegetables. Why does only one glass of fruit juice count? You can't get all your five a day in the form of fruit and veg juices, because juice contains very little fibre. Fruit squash doesn't count at all. Your at-a-glance portion guide So just what is one portion of fruit or veg? Here's a guide for adults (kids' portions will be smaller) for you to cut out and stick on the fridge. Fruit Small fruits: 2 plums, 2 satsumas, 2 kiwi fruit, 3 apricots, 7 strawberries, 2 handfuls of raspberries, 1 handful of blackberries, 3 tablespoons of frozen summer fruits Medium fruits: 1 apple, 1 banana, 1 pear, 1 orange, 2 halves of canned peaches Large fruits: half a grapefruit or a 2in slice of melon Dried fruit: 1 tablespoon Vegetables (frozen or fresh) 3 heaped tablespoons of cooked carrots, peas or canned sweetcorn 5 spears fresh asparagus Half a pepper 1 corn on the cob 8 Brussels sprouts 2 whole canned plum tomatoes 1 medium fresh tomato 3 heaped tablespoons of canned beans or pulses 2in piece of cucumber 8 cauliflower florets 1 cereal bowl of mixed salad