Sugar: Why You Can't Stop – and Why That Is Not a Drama

The question comes up almost every week at the gym: "Do I have to cut out sugar completely?" Usually it is followed by a video on somebody's phone – someone in a white coat explaining that sugar is basically the same as a hard drug.

Short answer: no, you don't. Long answer: it is still worth understanding what sweet food does inside your body. Because there is a solid reason why the packet of biscuits ends up empty even though you were full after the third one.

Your brain wants sweet – and has for tens of thousands of years

Your tongue runs a kind of quality control. Bitter means: careful, this could be toxic. Sour means: this could be spoiled. Sweet means: fast energy, take everything you can get. Even babies smile at sweet and screw up their faces at bitter – that is not learned, it is built in.

The moment your brain picks up a sugar signal – the sight of a dessert is enough – the reward system fires up. It releases the body's own messengers, which briefly lift your mood and drive appetite. The effect is so reliable that researchers have switched it off in the lab: people given a drug beforehand that blocks those messengers walked past the bowl of chocolate buttons far more often.

That is exactly where the famous dessert stomach comes from. It is not a joke, it is a program – one that saved lives in a world without refrigerators. It just keeps running today while you stand in the checkout queue.

Sugar is fuel, not poison

Your body does not want to get rid of sugar. It stores it: roughly 300 to 500 grams as glycogen in the liver and muscles. That is the tank for the heavy squat, the last set, the sprint to catch the train. If you train hard on a regular basis, you empty that tank constantly – and refill it with exactly this.

The problem only starts when the tank stays permanently full because there is too little movement and too much coming in. Then the surplus goes where nobody wants it: into fat stores, preferably around the belly and the liver. Over time that drives silent inflammatory processes which favour blood sugar and cardiovascular problems.

Fructose is a special case. It is processed almost exclusively in the liver – and converted to fat there particularly readily. That also applies to the supposedly gentle versions: agave syrup, honey, coconut blossom sugar. To your metabolism, all of it is sugar.

Not whether, but in what packaging

This is the most practical point. An apple and a glass of apple juice contain a similar amount of sugar – but something completely different happens in your body.

Whole fruit brings fibre with it. The food takes longer, travels further into the gut, and that is where the cells sit that tell your brain: enough. The further back, the louder that signal.

A smoothie or a cola skips the entire route. Nothing has to be chewed, barely anything digested. The sugar is in your blood before any satiety signal has even been sent. The same goes for white flour, crisps, toast: absorbed right behind the stomach, hardly any satiety, you keep eating. Wholegrain, pulses and whole fruit do the opposite.

One more thing: eating a lot of sweet food every day for weeks measurably shifts your preferences. Sweet becomes more attractive, everything else – vegetables, for example – loses its appeal. That happens quietly and without a decision.

Still: no panic

The opposite conclusion would be just as wrong. Blood sugar rises after eating – in healthy people that is not a disaster, it is proof that your system is working. Anyone tracking every fluctuation on a watch and getting anxious before every bite has not solved a nutrition problem, they have created a new one. I have seen people whose "I watch my sugar" turned into a relationship with food you could no longer call healthy.

For context: around 50 grams of sugar a day – roughly 16 cubes – is considered the upper limit. The German average is almost twice that. So this is not about the last five grams, it is about the half nobody eats on purpose.

What I tell people at the gym

• —Don't drink your sugar. Soft drinks, juices, smoothies – the most expensive form of calories there is.
• —Check the incidental sources. Fruit yoghurt, cereal bars, ready-made sauces, "protein" snacks. That is usually where the missing half is hiding.
• —Packaging beats abstinence. Whole fruit instead of juice, wholegrain instead of white flour. No ban needed, just a different form.
• —Enjoy deliberately instead of constantly. A proper dessert at the weekend beats five bars on the side – in calories and mentally.
• —Timing helps. Around training your body handles carbohydrates best. That is when the stores are empty.

And the most important point last: no single nutrient is the villain. First fat was to blame, then carbohydrates, now protein is supposed to save everything. What actually counts is the mix – and that you move. A slice of cake at a kid's birthday party has never ruined anybody.