It impairs memory and learning skills.
A 2012 study on rats, conducted by researchers at UCLA, found that a diet high in fructose (that’s just another word for sugar) hinders learning and memory by literally slowing down the brain.
The researchers found that rats who over-consumed fructose had damaged synaptic activity in the brain, meaning that communication among brain cells was impaired.
Heavy sugar intake caused the rats to develop a resistance to insulin — a hormone that controls blood sugar levels and also regulates the function of brain cells.
Insulin strengthens the synaptic connections between brain cells, helping them to communicate better and thereby form stronger memories.
So when insulin levels in the brain are lowered as the result of excess sugar consumption, cognition can be impaired.