Can you trust calorie counting?Accuracy of food labelling questioned
How many of us will be reaching for crackers and low-fat cottage cheese on January 1? Well, the 2011 New Year diet could mark a new way to count those post-Christmas calories, according to a British nutritionist.
Our old friend the calorie is how we measure the energy we get from foods. And the maths we use to count calories is Victorian. Really.
The calorie was invented in the 1890s by American chemist Wilbur Olin Atwater, who worked out that every gram of carbohydrate produced four calories, every gram of fat, nine calories, and every gram of protein, four calories.
Reaching these conclusions involved Atwater burning different types of food… and the human excrement they produced (yes!) to measure the energy they produced. Take one figure away from the other and, presto, you have the calorific values of various foods.
By 1896, Atwater had published “The Chemical Composition of American Food Materials” – a forerunner of the calorie charts which any regular dieter will have tucked into his back pocket.
Atwater’s findings have been treated pretty much as gospel ever since; you’ll find them on the back of your nearest packet of crisps, ready-meal or cereal box in the shape of a food label.
New calorie counting
This is where Dr Geoffrey Livesey comes into the picture. A well-respected nutritional biochemist based in Norfolk, Dr Livesey has worked for the Medical Research Council and a long list of universities, hospitals and research institutes.
He reckons Atwater’s calculations are, well, a bit too simplistic. Why? Because they don’t take into account the energy expended in chewing, digesting and metabolising food when it's converted into energy (an example of something called thermogenesis).
So foods which are more complex for the body to digest account for fewer calories than we might think. This means raw foods, proteins like meat or fish, and foods high in fibre, such as wholemeal bread, fruit, vegetables and pulses. Dr Livesey believes that proteins generate 20 per cent fewer calories than Atwater allowed for. Bring on the steak, raw veggies and wholemeal apple crumble then!
Dr Livesey’s work has already influenced that calorie-counters’ haven, Weight Watchers. The company this month launched its new “ProPoints Plan”, based on the idea of a “calorie delusion” – something it attributes partly to Dr Livesey, quoting him in its literature and even publishing his photo as one of its “experts”.
So Weight Watchers is now positively encouraging dieters to tuck into a cooked breakfast (protein rich!) over a buttered muffin with jam. Whereas both breakfasts used to account for 51/2 points under the company’s old plan, they are now worth 8 and 9 points respectively.
OK, so they’ve both gone up. And, oh alright, WW’s idea of a cooked breakfast is a slice of wholemeal toast with low-fat spread, a serving of tomato ketchup, a poached egg and two rashers of grilled bacon, but that should keep you going until lunchtime, shouldn’t it? As WW says, the cooked breakfast is “the better weight loss choice”.
Low-fat spread and grilled bacon. Raw vegetables and undercooked steak. Calorie delusion or not, these all sound suspiciously like an old-school diet. Atwater won’t exactly be turning in his grave.
So is this debate over chewing, chomping and digesting a bit of a storm in a teacup? Will 20 per cent fewer calories for a bunch of rather wholesome foodstuffs really make that much difference to dieters?
And should we change the labels on the back of our food packaging to reflect the new calorie-counting? Dr Livesey said: "There are no scientific reasons why we couldn't (alter food labels to allow for his findings). My preference is that the public should be told what is accurate and not accurate."
However, Sian Porter, a consultant dietician and spokesperson for the British Dietetic association says: “At the end of the day, it’s about the amount of calories you take in, versus the amount you burn off.
"With scientific measurement, there’s always a 10 per cent margin of error. If you looked up an apple [on a calorie chart], it would reflect an average of different brands.” Food for thought indeed.
This article was published on Mon 8 November 2010
Image © diego cervo - Fotolia.com
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