I’m not a fan of calorie counting…or using the scales as a means of measuring progress. That said, I know a lot of people who are so it’s worth discussing one of the biggest myths in fitness and that is that all calories are equal.
It’s often assumed that a calorie is a calorie is a calorie and, in some respects, that is correct. It is true that all “calories” have the same amount of energy. One dietary calorie contains 4184 Joules of energy so in that way, a calorie IS a calorie. However, it is significantly more complicated than that.
The human body is a complicated biomechanical machine that processes food differently. In cases where food is more difficult to digest, more energy from food is lost as heat and different foods and macronutrients have different effects and hormones that control hunger and eating behaviour. The foods we eat can have a huge impact on the biological processes that govern when, what and how much we eat.
Every calorie count on every food label you have ever seen is based on estimates or on modest derivations thereof. Yet these approximations assume that the 19th-century laboratory experiments on which they are based accurately reflect how much energy different people with different bodies derive from many kinds of food. New research has revealed that this assumption is, at best, far too simplistic. To accurately calculate the total calories that someone gets out of a given food, you would have to take into account a dizzying array of factors, including whether that food has evolved to survive digestion; how boiling, baking, microwaving or flambéing a food changes its structure and chemistry; how much energy the body expends to break down different kinds of food; and the extent to which the billions of bacteria in the gut aid human digestion and, conversely, steal some calories for themselves.
Nutrition scientists are beginning to learn enough to hypothetically improve calorie labels, but digestion turns out to be such a fantastically complex and messy affair that we will probably never derive a formula for an infallible calorie count. To start with, let’s consider digestion. Different foods go through different metabolic pathways and some of these pathways are more “efficient” than others. The more “efficient” a metabolic pathway is, the more of the food energy is used for work and less is dissipated as heat. Of the pathways, the pathway for protein is the least efficient. While protein may contain four calories per gram, a large part of the protein calories are lost as heat when it’s metabolized by the body.
It’s also worth considering the effect different macronutrients have on the body. Studies have shown that protein is the most fulfilling macronutrient, by far. In one study, those who increased their protein intake to 30% of calories automatically started eating 441 fewer calories per day and lost 4.9 kg (11 lbs) in 12 weeks. If you don’t want to go on a “diet” but simply tip the metabolic scales in your favour, then adding more protein to your diet may be the simplest (and most delicious) way to cause “automatic” weight loss.
It’s well known that different foods have different effects on feelings of hunger or satiety. There are many factors that determine the satiety value of different foods, which is measured on a scale called the satiety index. The satiety index is a measure of the ability of foods to reduce hunger, increase feelings of fullness and reduce energy intake for the next few hours. If you eat foods that are low on the satiety index, then you will be hungrier and end up eating more. If you choose foods that are high on the satiety index, you will end up eating less and losing weight. Some examples of foods with a high satiety index are boiled potatoes, beef, eggs, beans and fruits, while foods that are low on the satiety index include donuts and cake.
If there is one thing that health experts agree on (and there isn’t many) it’s that refined carbohydrates are not good for us. This includes sugar and refined grains such as white bread, biscuits etc. Unlike whole grains, refined grains contain low amounts of fibre and get digested very quickly leading to spikes in blood level, giving them the term ‘low GI’. This might not be so bad if you’re cycling the Tour de France but isn’t ideal if you’re sat at a desk. These spikes in blood sugar levels cause cravings for more sugary snacks and studies have shown that people can eat up to 81% more calories during a high GI meal compared to a low GI meal. The studies consistently show that people who eat the highest glycaemic index foods are at the greatest risk of becoming obese and diabetic. Because not all carb calories are created equal.
It’s clear, then, that not all calories are created equal. Different foods will have different effects on the body and experience different levels of digestive efficiency meaning it’s near impossible to use calories as a truly accurate means of monitoring energy intake. The margins of error are too large. I’m not saying to stop if you do count calories. There’s a great saying ‘It doesn’t matter how you find the pot of gold. All that matters is that you beat the leprechauns’. If you have success then carry on, what I am saying is to do is swap the ‘junk calories’ for healthy, wholesome food. 1000 calories of good food will give you more energy, nutrients and better foundations on which to build muscle or lose weight.