Artificial sweeteners and highly processed foods can shut off your "I'm full" safety valve.
Read the labels on the foods you eat, educate yourself.
Corporations want you to eat to excess, it's profitable.
There are also artificial sweeteners that are toxic to dogs even in small quantities, but humans can eat them all day with no ill effects. And it's not about body mass either, because humans might be say 2x the body mass of a dog, but we can eat 10 times the quantity and be fine.
Saying that a particular compound has an effect in laboratory test animals isn't really anywhere close to saying that it might be the same in humans, there is plenty of precedents to be said that it probably won't work like that.
Heard from sci show that they make you crave sugar more since they are stronger than real sugar. Also, they make your intestines absorb more sugar since the sugar receptors get clogged trying to absorb the artificial stuff and they pull more. That second one probably doesn't affect you very much though.
"Artificial sweetener" usually means something that stimulates your taste buds like sugar but cannot be metabolically processed for energy like sugar. HFCS is still actually sugar.
I think it's just sugar. At least I've heard that sweet things can kind of bypass your satiety. Most of us know the feeling of being full, but "having a bit of room for dessert"