Sugar can give your brain a little rush, making your mood suddenly better and get you ready to think fast. But when that spark becomes a habit, that’s when the problems start. Investigations made by the German Society of Neurology and the German Brain Foundation warn that sugar and glucose excess affect memory and debilitate the hippocampus, which is fundamental to learning things. Specialists at Harvard Medical School insist that thinking, remembering, and learning still depend on an adequate amount of glucose in the blood.
So, we need some, but not too much.
For people with diabetes, when sugar is low, they can feel mentally tired and attention issues, but when there’s excess for a long time, it complicates the neuronal function and the cardiovascular system.
In addition, work from the Max Planck Institute and Yale University shows that even little portions of sweets or fat can change our preferences, is like, the brain “learns” to look for them. Marc Tittgemeyer’s team observed that a prolonged consumption increases reward and reduces self-control. Lucía Correa de Ruiz warns about concentration and memory damage if there’s abuse.
As Frank Erbguth, from the German Brain Foundation, explains: “The dose makes the poison.” The brain needs glucose, but it also needs balance to protect what’s most important.
Energy: When it helps, and when it doesn’t
Our brains need glucose to work. A reasonable amount allows neurons to communicate and thoughts to flow around. That’s why when glucose is low, too low (common in diabetes), the neurotransmitters’ production stops, and attention slows down: learning becomes heavy, and mood also decreases. If we see it that way, sugar can be an ally in very specific situations, like just before studying.
The problem appears with excess. Too much sustained glucose alters neuronal plasticity and presses the hippocampus, which is basically the memory and learning center. That’s why the German Society of Neurology and the German Brain Foundation warn so much about it, because reducing sugar is taking care of our brains.
Then there’s the sweets habits: studies show that small doses of very sweet or fatty food can train the brain to want more (like that bag of chips that you don’t dare to open since you know you will finish it entirely), and the repetition reinforces the neural circuit.
The good news is that is about willpower; it’s actually that we need to teach our neurons.
What happens in the long term
Marc Tittgemeyer’s team found that chronic sugar intensifies the reward signal and weakens the brakes of self-control. This results in more impulsive “yes” and less reflective pauses. Which is a combination that only amplifies the repetition of sweet patterns.
Lucía Correa de Ruiz adds that sustained excess deteriorates concentration and cognitive performance, impacting directly on everyday memory.
In people with diabetes, the risks are even higher, of course. High levels of glucose and excessive sugar eating increase the production of beta amyloid (associated with Alzheimer’s) and damages cerebral vessels, elevating the probabilities of dementia in the future years.
Sweets? Yes, but under control
One dessert is not going to destroy your mind, but routine is important because it’s the habits, done and repeated day by day that can modify your brain.
What can help? Moderation. Harvard Medical School explains that in order to think well, we need a healthy glucose range. But don’t forget that “The dose makes the poison,” as Erbguth said. So the tactic is to stay in the middle: Combining foods instead of snacking on small sugar bites all day is a good choice. You can also try to notice how certain foods affect your approach—are you thinking slower or faster?
Don’t fight your brain; train it!