Get ready to have your mind blown about Kcalories

by Anne Myers-Wright RD/APD

Posted on Sep 8, 02:22 PM in and . No comments.

Are you a calorie counter? Get ready to have your mind blown.

A short time ago, Public Health England brought out a recommendation for calorie amounts that people should be aiming for at each meal. Most Dietitians were not in love with this idea, not in love with it at all! This was for a few reasons, one being that there was no discussion on food quality. I mean sure their recommendation may be to have around 600 Kcals for a main meal but that could mean 600 Kcal worth of junk! (err, of an unbalanced, poor nutritional quality meal that is).

Anyway, I digress.

So, what about calorie labels on products? Well…to be honest, calories on labels just aren’t accurate. They may be a general guide but nope, they are never ever accurate. Why?

Let’s look at what Kcals are. How are these creatures measured?

A Calorie (kcal) is the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius. Remember that from science class?

The Father of calorie counting was Wilbur Olin Atwater, a 19th Century nutritionist. He invented the Atwater system, which we still use today to measure calories. To do this, Atwater invented the calorimeter, which is also still used today. The original methods in these initial measuring techniques were considered flawed to some degree but to date, there has not yet been a suitable alternative. In fact, there have been recent discussions around inaccuracies on the measurements due to not factoring in the various idiosyncrasies of the human digestive system. For example, in 2012, they had to readjust the calorie counts for almonds as scientists discovered that we don’t digest as much as what was first claimed. Yes, we were able to eat more almonds than previously thought! Fab.

And what about on your food label?

Are you imagining that somewhere, a manufacturer sends in a sample to pop into the calorimeter? Well, no that’s not quite how it’s done. Atwater concluded that there were some average values we could use to calculate the calorie content of foods – we use the average values of 4 Kcal/g for protein, 4 Kcal/g for carbohydrate, and 9 Kcal/g for fat. Alcohol is calculated at 7 Kcal/g. (yes, these were on averages again)
So, a manufacturer will find out how much protein, carbohydrate and fat are in the product and the Kcals are worked out, backwards, from these.

The UK food standards agency regulations on food labels allow for different methods of calculating nutrient values. It does not necessarily require laboratory analysis and it may be possible for a food business operator to calculate the values themselves depending on the type of product.

Declared values must be based on:
•manufacturer’s analysis of the food
•calculation from the known or actual average values of the ingredients used
•calculation from generally established and accepted data

So, here once again, we must rely on different people calculating the amounts, batch differences, rounding, size variations etc.

So, all in all…just not accurate.

So where does that leave us?

Sure, Kcalories (or Kjoules) can be a rough guide for trying to aim for your recommended daily energy needs but please don’t fall for obsessively totting up the numbers from your food packages down to the last Kcal. Not only is life too short, it just isn’t right! What we should be doing instead of being slaves to the numbers is eating mindfully and thinking about the quality of the food and meals we eat. Counting calories just opens up a whole new world of restrictive eating and unhealthy attitudes to food and eating anyway! This is just one more reason to give it a miss.

So? Mind blown?

Photo: pixabay

Tags: Calories, Calorimeter, Food Quality, Kcal, Labels, Mindful Eating, Public Health England

About the author

Anne Myers-Wright

Anne Myers-Wright RD/APD

Anne is a Health Professions Council (HPC) registered dietitian (RD), an Accredited Practicing Dietitian (APD- Australia), a fellow of the Higher Education Academy (FHEA), a member of the British Dietetic Association, The Nutrition Society and of The Dietetics Association of Australia.


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