When sugar comes to mind, you probably think of table sugar, or sucrose. But this simple carbohydrate is made up of even smaller sugar molecules called glucose and fructose in an exact 50/50 split.

“Glucose and fructose are both monosaccharides – sugar molecules in the simplest form,” says Jamie Feit, RD, MS. “The body’s preferred source of fuel is glucose. Glucose is sourced by breaking down disaccharides or polysaccharides, which are larger sugar molecules. Meanwhile, fructose is found in its simplest form in fruits and some vegetables like beets, corn and potatoes.”

Like all sugars, both glucose and fructose are carbohydrates. But not all carbs are created equal! When we eat sucrose, the glucose and fructose molecules become split inside the body. The main difference between glucose and fructose – for our purposes, anyways – is how they are processed within your body.