That sentence is usually used as clickbait, and what comes after it depends on the claim being pushed.
If we complete it in a fact-based way, bananas are often said to “increase” things like:
- Potassium intake: true — bananas are a good source of potassium, which supports nerve and muscle function.
- Energy levels: partly true — they contain natural sugars (glucose, fructose, sucrose) plus fiber, so they can give a quick but steady energy boost.
- Satiety (feeling full): true to some extent — fiber helps you feel full.
- Serotonin / mood: commonly claimed, but oversimplified — bananas contain tryptophan, but it doesn’t directly “boost happiness” in a strong or immediate way.
If you tell me the full sentence or what you saw after “increases…”, I can break down whether that specific claim is true or exaggerated.