Comment by arcticbull

I think this is an example of proportionality bias. There's a cognitive bias that big effects (obesity, cancer, diabetes, etc) must have big and complex causes.

In reality, sugar is just straight-up bad in anything resembling the quantities we eat it, and we should not. It's addictive because there's very little of it in nature and it's high energy density. Therefore it makes sense to seek out. In our synthetic world, we can make as much as we want and eat it whenever we want.

The reward system exhibits unconstrained positive feedback.

As a counter-example there are tons of things that 'feel good' but are destructive, like opioids and cigarettes. Things that are addictive aren't de facto good for you. In fact they're usually very bad for you because they overload your reward feedback network.