Calories in and calories out doesn’t quite add up. We all know the role weight equals calories in, calories out. But wait, let’s think about this logically for a minute. If this rule was true, why can two people eat the same and exercise the same but end up a different. Weight?

Why can some people eat large amounts and stay slim whilst others can eat small amounts and gain weight?

We are not machines. We are complex beings. This is all evidence to suggest we have a natural built in mechanism within us that is trying to keep our weight at a natural set point.

Why aren’t we all way bigger than we are if we’re eating so much extra?

In his book, Dr. Andrew Jenkins breaks this down. In America, the average person eats approximately 500 extra calories a day, according to the calories in and the calories out equation. This would mean if we ate this much every year, the average American would gain 14. Stone is clearly isn’t the case, and in fact, the average American only gains a half a kilo.

How does it work?

What happens when your body-weight drops below your set point range, as, for example, might happen if you’ve been on a diet? When your body senses that your weight has dropped below the set point range, it feels happiest that a series of biological changes occur.

1). Your metabolism slows down. Metabolism is the rate at which your body uses energy. If your body thinks it isn’t getting the energy it needs, it slows down its metabolism and tries to preserve the energy it’s getting by storing it as fat in case it needs it in the future.

2). Your hunger level increases. Once the body has sensed that it might not have enough energy, it sends instructions to the brain that it needs to get out and find food. One of the ways that communicates this is by increasing circulating levels of the hunger, hormone, ghrelin. This motivates us to go out and look for food and lowers levels of a hormone. P. Y.

The one that tells us we are full. One of the impacts of this is that when our weight is lower than normal, we think about and crave food more. Not only that, but food actually becomes more rewarding. It smells and tastes better. All because our bodies are trying to get us to eat. This is worth thinking about. As is often when you’ve been on a diet for some time, your body weight drops below the set point.

Perhaps it’s not such a coincidence that this is when cravings and an increased drive for food. Hint. These factors work together to slow down the rate that the body burns energy and increases the drive to eat eventually, other than in cases where there is an actual famine. So there is literally no food to eat. Or for people who may have a particular medical condition or may be experiencing an eating disorder.

Biology wins the battle of even the strongest willpower, and when food is eaten, weight gain occurs. Until this point, weight is re-established. Importantly, studies have shown that the effect dieting has on metabolism and hunger levels can last for many years, even after people’s eating returns to normal.

This means that people can eat less than they could before they went on the diet, before they gain weight. Your body learned something important when your weight dips below your natural set point range. It learns that the world it’s living in isn’t necessarily safe, and it can’t guarantee the food the energy it needs will be available. Your body doesn’t know that you were deliberately trying to lose weight by going on a diet. It just knows that for a period of time there wasn’t enough food to keep you at the weight it feels happiest at. And now it knows this. It’s going to work extra hard to try and protect you in case that ever happens again.

The body can do this by actually increasing your natural set point. By increasing your set point, the body ensures it has an extra layer of energy. So next time there isn’t enough food available, it has some extra stores to help you survive a bit longer. And the next dot, you go on.

Guess what happens?

The set point goes up a little bit more. And again. And again. And again with each diet you go on thereafter. There is no exact science that can tell us exactly how much this that point increases by. And this will likely vary for each individual person. The evidence does show that people who have been on multiple diets tend to weigh more than people who have not. Although this is just hugely frustrating for people who are trying their best to do what they’ve been told to do, lose weight by going on a diet. This is actually the body doing its best to try and protect you and keep you alive.