Dr John Beaney

MB BS.  LRCP  MRCS (Retd)

www.johnbeaney.com.au                     

Calories in versus calories out.


Where dieting is concerned, calories have dominated our thinking for a long time. Nowadays there is a growing recognition that there is a lot more to weight control than comparing calories in versus calories out.
For a start, you may have some idea how many calories you have taken in over a given time, that is “calories in”, by laboriously studying one of the many calorie calculators. I am sure you would not have the remotest idea how many calories you had burned up in the same time.
You would need to know the basal energy needs of your body at rest, your heart beating, your brain thinking, your liver doing whatever it does, not to mention manufacturing red blood cells and the millions of other transactions taking place 24 hours a day.
And what about that night when you felt hot and threw off the bedclothes. How many extra calories did you burn off then?
Then, of course, you mowed the lawn one day, went for a jog another and then ran a marathon last Sunday.
Are you getting the picture?
Let’s suppose for a minute that calories in did have to balance calories out and let’s say you got it wrong. You should be eating 2,200 calories a day and instead you ate 2,400. Perhaps you’re like me and fancy macadamia nuts. You only take 7 but then you take another 7. Whoops, that’s 200 calories.
If you did that every day for 10 years you would gain over 80 kilos. (200caloriesX 365X10/9,000=81kilos (there are about 9,000 calories in a kilo of fat)).
Putting this in perspective, while 2,200 calories a day is probably about right for Mr and Mrs Australia, it is believed that we actually eat close to 3,400, just behind the Americans at 3,800 a day.
But it gets worse. Supposing you should eat 2,200 but instead you ate 2,000 calories a day. Well over 10 years you will lose 80 kilos. You would have shrunk to an embryo – or less.
Of course, none of this happens. While there are plenty of people around who weigh well over 200 kilos they didn’t get there by eating 14 macadamias too many.
I think we need to be looking elsewhere for an explanation.