All Calories Are Not Equal
Last week I was wandering around the supermarket. I had bought my fruit, veg, fish, chickpeas etc and was looking at the trashy magazines, planning a quiet evening in with a big bunch of grapes and a catch up of what the celebs were doing. But the headline that caught my eye was not what Brad and Ange were doing this week, or even the latest celeb diet which promised me I'd lose a stone in a week...but what caught my attention was New Scientist magazine. The headline read: These Burgers are identical...but one will make you fatter.
Well obviously I was intrigued. Horoscopes and celebs out the window, I started reading the article there and then. When I got a comment about it not being a library I paid for the mag and read the whole thing before I got to the car.
It was one of the most fascinating articles I have read in a long time. The basic premise was that the way calories are calculated might be completely incorrect- up to 25% out.
Now I have long believed that calories are not the key to long-term weight loss and health, as they don't take into account nutrient content. I would rather eat a bowl of natural muesli which is packed full of fibre, protein, vitamins, minerals and loads of other goodies, that a bowl of 'low calorie' cereal, which might be lower in calories but is low in everything else too.
Well apparently I am right!!
Calories have been calculated in the same way for over 100 years. The food is burnt in controlled conditions and the energy released from it measured. However our bodies don't burn food - they digest it. And when digesting food many factors can affect the amount of calories we can actually extract from it. It may also give a fuller explanation of why some diets are effective.
The example used in New Scientist is a great one. We want an afternoon snack, really fancying a nice chocolate brownie, but decide to be healthier and choose a nut based cereal bar. However when we check the label, there are 50 more calories in the nut bar...so we choose the brownie.
Now apart from all the other nutrients in the nut bar, the calories are very deceptive.
Fibre is a good example. It is very resistant to digestion so we do not absorb all the calories it contains. It also provides energy for the microbes in our gut so they take their cut before we get our share. This has lead to estimates that the calories in fibre rich food are 25% lower than listed on labels.
The calories in protein may be up to 20% lower as it takes energy for our bodies to digest it. Could this be one of the factors why (despite not being hugely healthy) diets like Atkins do make us lose weight?
Simple carbohydrates (the ones we should avoid anyway) like sugar, white flour and white rice are more easily absorbed and digested than complex carbs such as oats, wholemeal flour and brown rice. Meaning we get more calories from white bread or pasta than we do from wholemeal. Even though the
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