- 170 calories labelled on a serving of almonds can be closer to 129 calories
- However, calories in processed foods can often exceed the labelling
- This is because people digest differently due to the type bacteria in their gut
- Instead of reading labels for calories, a more reliable approach to lose weight may be to stick to raw or wholefoods which are harder to digest
Don't rely on counting calories if you want to lose weight, scientists warn.
Much of the nutritional data on labels is based on outdated 19th century science.
And the way food is cooked – as well as an individual’s metabolism – can make a dramatic difference to how many calories are absorbed.
Scientists warn the number of calories on nutritional labels can differ wildly from those we actually absorb. One reason is that many foods simply pass through the body undigested, as we lack the tools to break down seeds and tough fibres
A study found that instead of the 170 calories in a one ounce serving of raw almonds, only 129 calories are taken in.
In contrast, when eating processed foods such as sugary cereals, the number of calories often exceeds the labelling.
Mice fed raw sweet potatoes lost more than four grams of weight, while they gained weight when given the same amount of cooked food.
Another problem is that even if food is cooked in the same way, each individual digests it differently thanks to the type and abundance of bacteria in their gut.
The obese may have an over-abundance of certain types of gut bacteria, making them more efficient at absorbing calories. Biologist Rob Dunn from North Carolina State University said the current system of calculating calorie labels is outdated.
Writing in the journal Scientific American, he said: ‘In the end, we all want to know how to make the smartest choices at the supermarket.
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For those intent on losing weight, instead of reading the calories, a more reliable approach may be to stick to raw or whole foods which are harder to digest.
A cheese sandwich made with wholewheat bread is harder to digest than one using a white loaf. As a result, the former has 10 per cent fewer calories.
Food experts also warn that calorie labelling has for years ignored the energy content of fiber. This means that dieters have been ‘unknowingly’ eating more calories than they thought in their muesli or porridge.
As a result, an average bowl of bran cereal contains an extra 20 calories, they claim. The calorie content of protein has also been exaggerated by up to 20 per cent because the current system does not take into account the extra energy used in chewing.
In contrast, when eating processed foods such as sugary cereals, the amount of calories we receive can exceed the labelling. For those intent on losing weight, instead of reading the calories, a more reliable approach may be to stick to raw or wholefoods which are harder to digest, claim scientists
