
24/09/2025
Brain fog or lack of focus – Glucose crashes can cloud your mind and slow your thinking.
A glucose crash; also known as reactive hypoglycemia - can slow down thinking because your brain relies almost entirely on glucose for energy. When blood sugar drops suddenly after a spike, the brain doesn't get enough fuel, which affects cognitive performance.
The brain uses about 20–25% of your body's glucose supply at rest.
It has no way to store glucose, so it depends on a steady supply from the bloodstream.
After eating a high-sugar or high-carb meal, blood sugar spikes.
The body responds by releasing insulin, which helps cells absorb glucose.
Sometimes, insulin overshoots, causing blood sugar to fall too low - that's the crash.