The most surprising piece of research is on how fruit affects your brain-derived neurotrophic factor (BDNF), which is a component that helps you learn and form new memories. Sugar lowers this component, meaning you can struggle at puzzles or studying or remembering things. Even more concerning is the increased links between low BDNF factors with depression and even dementia.
What's more, all sugar is addictive. It prompts your brain to release the 'reward' hormone dopamine, which then naturally makes you want more. What's more, a study from the University of Southern California found that people who consumed fructose experienced more cravings than if they ate foods with glucose. And as with other addictions, withdrawing from sugar can actually cause uncomfortable symptoms, including shaking, anxiousness, and teeth clenching. Therefore, it is important to cut sugar gradually, eliminating the most obvious sourcing, with an aim to eating as little processed then fruit sugars as possible.
Of course, there are more nutritional benefits to eating a piece of fruit over say, a cookie. But, to keep your brain happy and healthy, opt for fruits that are lower in fructose, such as green apples, berries and watermelon.