table sugar (sucrose) is a compound made up of simpler molecules: fructose and glucose. fundamentally, it is a carbohydrate your body uses for energy. when sugar is digested, the enzyme sucrase in the small intestine splits these two molecules apart and they both get absorbed into the bloodstream.
the difference between eating a banana and drinking a small can of soda, despite the similar sugar levels, is fiber. fiber slows sugar absorption which blunts the blood sugar spike in the body.
this is the usual order of things:
step #5 leads to the first symptom of excess sugar intake: leftover glucose gets converted to fat. in large amounts, the body uses the liver to process fructose and pack it into triglycerides which raise blood fat levels and contribute to visceral fat (the body fat in your abdominal area).
fructose also spikes ghrelin (hunger hormone) while suppressing pyy (fullness hormone) meaning it actively makes you want to eat more (non-alcoholic fatty liver disease is also a concern as the liver processes fructose similarly to how it processes alcohol).
the list goes on: excess fructose can lead to non-alcoholic fatty liver disease (nafld), high-sugar diets are consistently linked to elevated markers of systemic inflammation which is behind heart disease, certain cancers, arthritis, and elevated cortisol -> elevated cortisol is known to suppress both testosterone and human growth hormone, which are the two main drivers for muscle growth in men.
Sources:
https://www.dartmouth-health.org/articles/what-sugar-does-your-body
https://www.health.harvard.edu/diabetes-and-metabolic-health/the-sweet-danger-of-sugar