When it comes to food, there is so much conflicting opinion. One week bread is bad, the next it’s a superfood… give us a break! With so many ‘influencers’ promoting dangerous weight loss products, there is no better time to discuss nutrition.
Calories are a very controversial topic and are often spoken about as if they’re the enemy. Once you understand how they work, it soon becomes clear that they are quite the opposite, after all, they do fuel your body! The opinion that calories are the most important part of a diet, and the calorie-counting that comes along with it, is extremely damaging.
Imagine you are on a calorie-restricted diet and you have 100 calories set aside for a snack. You could choose to have a banana, but for the same calories, you could have 4 squares of Dairy Milk… which would you go for? It doesn’t matter which you choose because they both contain the same number of calories and a calorie is a calorie, right? Wrong.
What is a calorie?
A calorie (kcal) is simply a unit of measurement, used to show how much energy our body gets from food and drink. 1kcal is the amount of energy needed to raise 1kg of water by 1°C. Without this energy, all the cells in your body would die, which is why it’s important to keep your body fuelled.
While it is true that all calories contain the same amount of energy, once they enter your body it’s a whole new world. Different foods will take different biochemical pathways to break the food down and extract the energy it needs. Each macronutrient (carbs, fats and protein) also has a different effect on hormones and the brain centre controlling hunger and eating behaviour.
Let’s explore the reasoning behind calories not being equal in more detail.
1. Metabolic Pathways
When food enters your body, the energy it contains isn’t readily available and needs to be processed (metabolised) to release the energy. The metabolic pathway is a series of chemical reactions which eventually leads to the conversion of food to energy. Some pathways are very efficient; however, others need to use some energy in the process.
Fats have the most efficient pathway, with only 2-3% of the energy being used during metabolism. On the other hand, proteins use 25-30% of the total energy while being metabolism. Carbohydrates are similar to fats at 6-8%. To put this into perspective, eating 100kcals of protein would end up as 75kcals once it’s been metabolised, however, 100kcals of fat would end up as 98kcals.
2. Simple Sugars
Fructose and glucose, two types of simple sugars, contain the same number of calories but the way they behave in the body couldn’t be more different. Fructose is in fizzy drinks, sweets, granola bars, juice and more, while glucose is found in foods like pasta, wholegrain bread, fish and milk.
After eating foods containing fructose, a hormone called ghrelin increases. Ghrelin is a ‘hunger hormone’ which stimulates appetite, increases food intake and promotes fat storage. When you eat glucose, which has the same calorific value, ghrelin levels decrease!
3. Glycaemic Index
Some foods may contain the same number of calories but have a higher glycaemic index, for example, whole grain vs. white bread. A glycaemic index is a measure of how quickly a food raises blood sugar. Foods with a high glycaemic index, namely refined carbs, are usually low in fibre and are digested and absorbed quickly which leads to spikes in blood sugar.
Eating these foods can take you on a blood sugar rollercoaster, leaving you craving high carb snacks during the blood sugar crash. Giving in to these cravings can get you stuck on the rollercoaster!
So there you have it, due to these complicated processes going on inside our bodies, calories should never be taken at face value. Food and drink should instead be evaluated on nutritional value, which is much more important to proper body functioning. So, time to delete that calorie counting app and focus on eating foods that make you feel fabulously full of energy!