system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If all carbohydrates get broken down to their most simple form, sugar, why is it unhealthy to just eat tablespoons of sugar?
gpt
Most of the dangers come from the glycemic response to these various foods.

Pure sugar with nothing to slow the absorption rate will spike your blood sugar. This causes your pancreas to release Insulin to counteract that spike, which in turn reduces your blood sugar below normal levels, so your body releases glucose into the blood stream to compensate, which spikes it again, causing your pancreas to release more insulin... Lather, rinse, repeat until your glucose levels have hit a steady baseline.

This yo-yo effect taxes your pancreas significantly, as well as has other downstream effects on your body. 

The more effort it takes your body to absorb the sugars, the healthier it is for your system when consumed in moderation.