Zero-calorie drinks are popular alternatives to the sweet varieties but zero-calorie foods are still some way off. Yes, there are almost calorie free foods, including celery, which contains about 6 calories per stem and cucumber which has about 40 calories, but the idea of tucking into a zero calorie burger with no-cal fries on the side is stuff of futuristic fiction.
Manufacturers can easily produce no cal fizzy drinks. They replace the high-calorie sugar with tiny amounts of potent sweeteners such as aspartame and acesulfame K and then add water to replace the missing sugar bulk.
But their task is harder when it comes to making zero-calorie foods because with current food technology any solid ingredients, like carbohydrates, still contain calories.
This explains why there are many reduced-calorie and low-fat products available but as yet no calorie-free foods. The race is on among ingredient makers to discover the zero-calorie substances that food producers can work with to develop a range of calorie-free foods produced from no cal ingredients but which taste as good as conventional ones.
Food manufacturers are already part way there with the help of specially produced ingredients like fake fats which, as well as sweeteners, can reduce the calories in foods.
One such material is the laboratory-made fake fat sucrose polyester. It’s formed by combining two natural substances, sugar molecules and fatty acids, and as it’s neither digested nor absorbed by the body, can reduce calorie intake from fat in the diet. One version of sucrose polyester known as Olestra has been developed as a tasteless fat substitute and is used in the US in crisps, biscuits and tortilla chips and instead of oil to fry savoury foods.
Professor John Hunter, consultant physician at Addenbrooke’s Hospital, Cambridge, led a three-month study of UK volunteers looking at the effect of sucrose polyester (not the brand Olestra) on the gut. He said: ‘It can’t be digested and so as it passes through the body it removes fat-soluble vitamins, particularly vitamin E. To compensate it’s now fortified with vitamins A, D, E and K.
‘We found it made stools looser and more frequent and there were cases of anal leakage and stained underwear. On the plus side, however, it has a small effect on removing cholesterol from the body. High cholesterol is a major risk factor for heart disease.’
But do zero-calorie ingredients make it easy to slim and stay slim by reducing fat and sugar consumption and so help reduce obesity?
Dieticians warn we shouldn’t rely on zero or low-calorie foods and drinks at the expense of others to lose weight. Nigel Denby, a registered dietitian based in the UK, says: ‘They’ll never make a bad diet good and may encourage complacency towards making healthy lifestyle changes. They don’t encourage taking responsibility for what you consume and changing your diet for the better. People shouldn’t think because they have calorie-free cola drinks and fat-free cakes, they can eat chips all the time.
‘If you only buy and eat these types of foods there’s danger of missing out on other nutrients, for example eating cereal bars with added sweeteners means you won’t get the nutrition that’s available in fruit and nuts. You could end up replacing everything in your cupboard with these products and miss out on nutrients in other foods and drinks.
But he adds: ‘If you enjoy a relatively healthy diet and are fairly active, and like to have a fizzy drink on your desk at work, then that’s fine.’
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