The truth's in the trolley

All of us have trundled down the aisles with the best of intentions, only to be tempted by the odd cream bun or ready-made meal. Now Sainsbury's is employing shopping consultants to help people buy healthily. According to a recent study, more than half of British adults are overweight, partly because we are unaware that our favourite foods are more unhealthy than we think. Nutritionist Hannah Theobald believes a lot of the confusion comes down to labelling. "Reduced fat" foods, for example, can still be high in fat.

Nutritional labelling can be daunting: it must by law show either four or eight elements: calories, fat, protein and carbohydrates or, additionally, sugar, fibre, saturated fat and sodium. Sodium is multiplied by 2.5 for salt content. You then need to relate these figures to your ideal daily intake: for the average woman between 19 and 50, this is 1,940 calories. The recommended salt intake is 6g; fat consumption 70g and saturated fats - implicated in heart disease - no more than a third of that.

So what does this mean to the average shopper? Claudia Kirlew, 32, is an IT consultant. At 5ft 1in and just under 10 stone she would love to lose another stone-and-a-half. She thinks her typical weekly shop is averagely healthy. We asked Hannah Theobald to give her verdict. (Fat/calorie measurements are per 100g unless otherwise specified.)

Fruit and vegeatables

Claudia buys:

Baking potatoes, sweetcorn, oranges, squeezed fruit juice, oven chips.

The nutritionist's view:

"Oven chips are lower in fat than fried (4.2g of fat against 9.6g) and fruit juice counts towards the recommended five portions of fruit and veg a day. But there should be more fruit and veg (one third of the diet). The fibre helps fill you up, as well as providing vitamins and minerals. Buy fruit to snack on."

Meat, fish and alternatives

Claudia buys:

Chicken leg/thigh quarters, vegetarian sausage, sirloin steak (for a bi-monthly treat).

The nutritionist's view: "Vegetarian sausage isn't necessarily low-calorie or low-fat, but it's better than the real thing (9.4g fat, 179 cals against 22.1g and 294 cals). Buying skinless meat fillets reduces fat (from as much as 19.9g to 2.2g); buy smaller, leaner cuts and eat more vegetables. Eat fish twice a week (once white - low in calories and fat; once oily - good for the heart)."

Convenience meals

Claudia buys:

Fish-and-chip ready meal; three Pizza Express pizzas, one 12-inch, two seveninch; cheese-and-onion pasties (frozen).

The nutritionist's view: "Too much convenience food - a real calorie heavyweight. You can buy cheeseless pizza and add your own vegetables. But why buy convenience fish and chips when oven chips and grilled white fish are just as quick?"

Milk/dairy

Claudia buys:

0.5 litre choc milk shake, 1.5 litre soya milk drink, block of Cheddar, semiskimmed milk, Flora Lite margarine.

The nutritionist's view:

"Choosing semi-skimmed over full fat is good (wholemilk has 3g of fat, semi has 1.7g, skimmed 0.2g); soya drink has 1.6g of fat - and soya protein can help the heart. Lite spread rather than full fat is good (38g fat, 357 cals against 59g, 531 cals). Aim for two to three portions of dairy products a day (one portion is a 30g piece of cheddar, 150g of yoghurt or a 200ml glass of milk)."

Fatty/sugary/snack

Claudia buys:

Large strawberry bio-yoghurt, a pack of seven crisps, Cadbury's chocolate cake, two bottles of coke, olives with feta, strawberry jam.

The nutritionist's view:

"Yoghurts are a source of calcium (see dairy) - avoid high-fat Greek ones and those with novelty sweet flavourings which you add. Olives are high in monounsaturated fat, beneficial to heart health; feta is better than Cheddar (at 20.2g of fat and 250 calories, against 411 and 34.9g). Diet coke would be preferable to ordinary (1 cal compared with 41 cals). Crisps are really high in salt and high in fat - a 35g bag has 180 calories with 11g of fat and 1g of salt per packet. If you must, buy singles, instead of multi-packs."

Bread and starchy food

Claudia buys:

White English muffins, hot-cross buns, loaf of wholemeal bread.

The nutritionist's view:

"Wholemeal fills you up and provides more fibre than white. Muffins are okay, but avoid fatty marg or butter - it all adds up. Bread, along with wholegrain cereals and starchy foods, should make up a third of your diet. So there is not enough here."

Indulgence

Claudia buys:

Steamed puddings, strawberry jam, strawberry cheesecake.

The nutritionist's view: "Foods rich in fat and sugar should be limited or at least reduced, and jam should be spread thinly. Healthy versions can still be indulgent but tend to be better than standard products - check the nutrition panel. Most of them have upper fat limits - for instance, less than 4g of fat per 100g. A rice pudding might have as little as 0.8g. Try fruit salad with meringue (381 calories per 100g)."

Alcohol

Claudia buys:

Bottle of Jacob's Creek wine.

The nutritionist's view: "Alcohol adds calories. Wine has around 66 cals in a 100ml glass. Guidelines are two to three units a day for women (1 unit is 25ml of spirits, or 125 ml of wine, or half a pint of mild-strength lager), three-to-four units for men."

Tips for lighter shoppers

Never go shopping when hungry

Always make a list and stick to it

Don't buy things to eat on the way home

Avoid danger aisles

Avoid sweet or high-fat treats

Read the nutrition labels