Breakfast with a pastry, bottled juice and coffee with three teaspoons of sugar is the fastest way to teach your body it needs fuel every two hours. Nutritionists are increasingly pointing to one simple change that reshapes an entire morning: protein in the morning, instead of pure sugar.

The logic is in blood sugar. A breakfast full of sugar and empty of nutrients gives a quick energy spike followed by a crash - and so the body is trained to constantly demand fast fuel. "Protein in the morning is essential, because it greatly helps regulate hunger and energy throughout the whole morning," explains a specialist in integrative medicine and nutrition. Protein delivers a gradual glucose response, a longer feeling of fullness and a signal to the brain that the body is well fed - especially when combined with fibre and healthy fats.

Concretely, that means avoiding industrial biscuits, pastries, cereals and bottled juices, and bringing in quality proteins, healthy fats (olive oil, avocado, walnuts) and slow-digesting carbohydrates instead. Three practical examples: eggs with ham and fruit; natural yoghurt with berries and oat or buckwheat porridge; or sourdough bread with avocado and salmon.

Interestingly, the expert plays down the question of the exact time you eat. While the body naturally works better during the day, when exactly you have breakfast matters less than was once thought - what matters more is listening to your own body. And when you're on the move, the advice is the same: reach for whole foods - boiled eggs, walnuts, yoghurt, kefir - and leave dessert for after the meal. Nothing revolutionary, just the logic the fast-breakfast industry would rather you didn't hear.