Calorie Counts On Food
Labels Could Be Off By 25%
The first thing most of us do when we pick up supermarket food is look at the calorie content.
But we might be wasting our time because calorie counts on food labels may be out by as much as 25 per cent.
However this could be welcome news for dieters because it has emerged that many foods are less calorific than billed.
That small pepperoni pizza has 386 calories compared to the 422 stated on the label.
Scientists have called for the existing calorie count system - devised in 1889 - to be scrapped and replaced by a more accurate method.
They believe the current method 'cheats the consumer' as it fails to account for the energy used to chew and digest the food.
As a result some foods appear more fattening than they really are and some less.
A chocolate brownie's label may claim it has 250 calories, compared with 300 calories in a muesli bar, but under a new proposed system the calorie content in both would be the same - 275.
This is because the brownie is easy to digest so the body absorbs all the calories whereas a percentage of the muesli bar will pass, undigested, through your body.
You also burn up more calories chewing and digesting the muesli bar.
With an extra 20 calories a day leading to an annual weight gain of 2lb, there is mounting pressure to make the system more accurate.
Independent nutritionist Dr Geoffrey Livesey, who formerly worked for the Medical Research Council, is among a growing band of scientists calling for a new system.
'We need to take into account all the considerable knowledge we have learnt since 1889 and start applying it,' said Dr Livesey.
'An error in accuracy of 25 per cent is simply not good enough. And with some prepared meals containing a number of foods, the level of inaccuracy can be as much as 50 per cent.
'The consumer is being cheated by not getting the right information.
'People on strict calorie controlled diets cannot rely on food packaging when trying to lose or gain weight.'
The existing method of calculation was created 120 years ago based on tables put together by American agricultural chemist Wilbur Olin Atwater.
Using a device called a bomb calorimeter, Atwater burned food samples and measured the amount of energy released from the heat this produced.
He then estimated the amount of this energy the body used up, by calculating the energy of undigested food in faeces and other waste products.
Atwater concluded that every gram of carbohydrates produced four calories, every gram of fat, nine calories and every gram of protein, four calories.
Ever since these figures have been taken as gospel.
However new research by Dr Livesey, and others, has shown that the amount we digest certain food varies.
Therefore the calorie content of food should be re-calculated according to its Net Metablisable Energy - the figure showing the amount of calories food leaves for your body to use after the calories used in digesting it have been subtract.
His findings were reviewed by the World Health Organisation in 2007, which concluded his research was sound.
Despite this, government body, the Food Standards Agency, has rejected calls to adopt the system.
Dr Livesey said the discrepancies also call into doubt the ability of the food regulators to punish manufactures who publish in accurate calorie information.
'Manufacturers are punished by regulators if they publish inaccurate calorie information.
'There is a degree of injustice here. Should manufacturers be punished if the system is itself just as inaccurate?'
The recommended daily calorie intake for a woman is 2,000 and 2,500 for a man.
A spokesperson for the FSA said that Mr Livesey's research was of 'legitimate scientific interest' but would not have sufficient impact on overall diets to warrant changing calorie counts on packaging.
March 15, 2010