It’s been a long held belief that the human body is a relatively simple machine. We eat for energy and if we eat too much we get fat. So people have always maintained the stance that calories are the all important measurement of how fattening an item of food can be. But is this correct?

The simple answer is No.

Going back to basics, the human body uses fat as an energy store on a dynamic basis. Energy is shuttled in and out of fat stores on an almost continual basis. There are countless factors that lead to fat storage and fat burning, but by default the body will try to maintain homeostasis, keeping its internal structures and levels constant. The body’s complex processes ensure we don’t get too hot, too cold, too fat, too thin, too hungry, too full etc….

One factor that does impact metabolic processes is calorie consumption. If we take in more energy then the body must do more things with that energy. To maintain the balance it will adjust hormone levels, appetite, temperature and tiredness to name just a few. Think about the last week, or the last year, or the last decade. How much weight have you put on or lost? It will be minimal. Yet the dieticians on TV tell us that eating an extra 30 calories over our “daily maintenance allowance” will put on a pound a month. And I can guarantee that you’ve not been calculating your energy intake and expenditure to within 30 calories every single day. So why aren’t people getting fatter and thinner, and fatter and thinner all the time. The reason is that the body is able to handle these small fluctuations through mechanisms such as making us more active and increasing body temperature. The body just burns off the excess. Studies show that if we eat more then we exercise less the following day, and if we exercise more then we get hungry and eat more. We subconsciously balance our intake and expenditure. This is one of the reasons why calorie counting and steady state aerobic exercise do little in the long run to burn fat.

Think about this. When the doctor tells us we’re overweight, he asks us to eat less and move more, e.g. Have smaller meals and go for a run. Now think about when we’re going out for a big meal. Beforehand we do the same, we eat less and do some exercise to “build up an appetite”. So the doctor’s advice to help us lose weight is to encourage us to build up an appetite. Genius. And people wonder why this general advice doesn’t work.

Critically there is a point where calories do shift the balance. Unless you’re an elite athlete, if you eat 5,000 calories a day you will get fatter. The corollary of this is that in a very controlled exercise and fixed dietary plan, a calorie deficit can and often will make a difference. But this difference is minimal. If you want to lose fat then start with cutting out crap, reduce the carbs and eat Paleo. A great diet that works for me is here

If you want to read up on this then the book to read is The Diet Delusion by Gary Taubes (aka “Good Calories Bad Calories” in the USA). It is a very big book, but a damn good one. I warn you, this book is the nutritional equivalent of the Matrix Red Pill. Once you have it there is no going back, you will join the “real world” and you will question everything you’ve ever thought true.