Why calories are not made equal

You’ve probably seen the advert or similar…

Bag of sweets 100 calories vs. Broccoli 100 calories.

Sure, they’re both 100 calories and lets face it, we all know which one we’d choose!

However, once they enter your body, the rules change. Your body is a hugely complex biochemical machine, with various different process and pathways for dealing with food. This results in different hormones and areas of the brain being activated to signify different chemical messages, such as “I’m hungry” or “I’m full”.

So, lets take a look at why a calorie is not a calorie inside our bodies.

Metabolising food

Some nutrients take more effort than others for our bodies to metabolise. This process is known as the thermic effect of food and essentially means that we actually burn a percentage of the calories consumed in order to metabolise the nutrients from the food.

Certain nutrients have higher thermic effects than others. Protein is by far the highest and can create a thermic effect of up to 30%, meaning for every 100 calories consumed, roughly 30 are used in the process of metabolising.

As you probably guessed, this makes it harder for you to over eat, and actually means you require more calories per day.


Without entering into the ‘sugar war’, it’s important to consider the effects of fructose and glucose.

Before we go further it’s important to note that, fructose refers to added sugars, not those found in fruit.

As simple sugars, both fructose and glucose are considered very similar, in fact they appear and are chemically almost identical. However, when consumed, your body has a very different opinion.

Glucose can be metabolised by any of the body’s tissues, whereas fructose is only processed in the liver. The real problem comes when we start to look at the effect it has on the body’s hormones.

Ghrelin, the ‘hunger’ hormone that lets you know when your body is full or not, has been linked with being raised to signify increased hunger as a result of consuming fructose.

Fructose also doesn’t cause hunger centers in the brain to display the same level of satiety (fullness).  It can also lead to insulin resistance, meaning increased abdominal fat gain.

Blood Sugar Levels

Regulating our blood sugar levels can have a huge impact on how we feel and also on weight loss.

Eating foods, which are classed as ‘simple carbohydrates’ or rank highly on the glycemic index, can lead to a spike in our blood sugar levels or an increase in the release of the hormones insulin.

This leads to our energy levels shooting up and then crashing. Following the crash we often crave something sugary, which repeats the cycle.

Whilst our energy levels are yo-yoing, what is happening inside our body is that the excess energy (or glucose) created from the food we’ve eaten is now being shuttled around the body (following the release of insulin).

First, the glucose will be taken to the necessary organs but as soon as they are full, it gets stored in our adipose tissues, which is known as fat. The more we repeat this cycle the more resistant our bodies are to insulin and the easier we store fat.

How do we make calories count?

Simple changes to diet can go a long way.

Stick to unrefined or natural foods and avoiding sugary snacks is a great start.

For most, consuming unrefined or complex carbohydrates that are high in fiber will greatly decrease the effect on blood sugar levels and definitely aid a weight loss plan.