Thursday 6 January 2011

The Calorie Myth Exposed


Back in the 1800’s when Wilbur Atwater ‘discovered’ the calorie I wonder if he knew what a stink he would cause in years to come.

By using a bomb calorimeter to measure the energy value of food, scientists now had a way of quantifying food in terms of energy density and thus could calculate what was consumed at mealtime.

Years later by simply equating energy consumption during activity or output, the scientists would have a neat little theory called ‘the energy balance theory’ and the oppression of the calorie was born.

The prevailing nutritional wisdom dictates that if you eat less and move more you will be slim and beautiful. Conversely if you move less and eat more you become a fat pig.

Far be it from me to question something that has existed for years with such success (note my sarcasm), after all our population has been getting fatter in spite of the energy balance theory, however this very simple theory (and it is a theory) has some shortfalls.

Perhaps it’s to do with people’s infatuation with measurement. People do tend to believe what they can measure and it does give them some satisfaction to see quantifiable changes. We see this in every aspect of life from education and our dependence on exams to finance and the economy.

However, when it comes to health this highlights the shortfalls in ‘science’ and modern living. With weight-loss being on such high agenda for many, food manufacturers, the media and the government have taken what was once a theory as an absolute truth, and with it has spawned an entire cottage industry with the calorie at the helm.

Now I realise I’m putting my neck out here and by many will be criticised for being ‘anti-scientific’ but I beg you to question do calories actually measure what they are supposed to? And is there really anything of use and enlightening about knowing the energy value of food?

The medical profession will tell you ‘a calorie is a calorie is calorie’ and ‘the only way to lose weight is to eat less and exercise more’ and that ‘a diet that doesn’t count calories is a ‘fad.’ But dare I say it, and they know this more than me, the human body is complicated.

At any one time all manner of chemical reactions are occurring within the human body. With regard to weight loss some of them are positive and some are negative. As you read this you will have a variety of enzymes, hormones, neurotransmitters and other compounds creating what is commonly known as your metabolism.

The assumption that everyone has the same metabolic reaction to a given food from entry to exit is perhaps the calories first shortfall. This theory doesn’t take into account individualistic nature of the human being. Just as we look different, we function differently too. Some of us can eat spicy food - some of us cant. Some of us can eat bread – some of us cant. The unique nature of the human biochemistry is very much that – unique.

I’m not saying that calories have nothing useful to tell us – I just don’t think they are telling the whole storey. For the most part people are quite greedy and could stand to eat a little bit less. Calories provide an insight, but the energy balance theory has its shortfalls.

Perhaps another reason to question the calorie is very nature in which a calorie is calculated. The bomb calorimeter equates a calorie by burning a food and measuring the ash. To determine how much energy was released and how much energy was contained in the molecular bonds was dependant on how much heat was omitted. In essence the calorie is a measure of heat – one calorie is the measure it takes to raise the temperature of one litre of water. Scientists measure the amount of calories in food by burning it.

Aside from the obvious criticism – we don’t burn our food to create energy, the temperature of which one litre of water will increase is also dependant on several factors - most notably elevation. You can boil one litre of water at 100c at sea level, 96 degrees at 6000ft and 72 degrees on the top of Mount Everest. So if the degree at which water changes temperature varies what use is the equation anyway.

If you think my point of view is restricted to input – I believe the same for output. If you believe the fancy bit of equipment at your gym that tells you the total amount of calories expended as you get off of it is accurate you should think again. How can it accurately estimate calorie expenditure from your age and weight – it can’t. The truth is it’s just a great way of selling treadmills.

Like I have said we are metabolically unique. To assume we metabolise calories in the same way is foolish. I don’t think the energy balance theory is completely wrong – most people do need to move more and eat less. I just think our infatuation with it needs to stop. We are biochemically and physiologically different – just as we look different we function differently.

Counting calories accurately is difficult and time consuming. It also leads to obsessive behaviours. Go to any diet club up and down the country and you will find a group of people who can rattle off the calorie value of any food in the supermarket. These people are none the wiser for it.

My advice to you is that calories DO count, just don’t count calories.

1 comment:

  1. Great article Steve, you've hit the nail on the head there mate.

    ReplyDelete