Here's why:

* Sugar: Simple sugars like glucose and fructose are quickly absorbed into the bloodstream. This is because they are already in a form that the body can easily process.

* Beans: Beans are complex carbohydrates containing fiber and starch. These need to be broken down by enzymes in the digestive system, which takes longer than simple sugar digestion.

Here's a quick breakdown of the digestion process:

* Sugar: Digestion begins in the mouth with saliva, and is mostly completed in the small intestine. It's then absorbed into the bloodstream.

* Beans: Digestion begins in the mouth, but the majority of breakdown happens in the small intestine. The fiber in beans takes longer to break down and can even reach the large intestine.

Therefore, sugar will give you a quicker energy boost, while beans provide a more sustained release of energy due to their slower digestion.