Sugar is a type of carb. Refined and broken down to the most basic type, but still a carb.
To feal full is mainly determined by potion size not by calorie density, so to feel like this eating vegetables is actually a good idea.
That said, if you gulp down tons of food like this landwhale probably does, your regulation system grows accustomed to that sizes.
Some of you may experienced the other way around while dieting; you eat smaller portions to reduce your calorie intake for a while and then when you eat after a while a portion in your old normal size you'll feel stuffed.
That's why gastric bands sometimes don't work. Some people are so persistent in their gorging that they wear it out.
And while I'm at it, fun fact; if you manage to reach a body mass index of 35, your chances to ever reach a healthy weight again (without operation) will drop abysmally low.
So I don't wonder at all, that uppercase Whale here didn't manage to lose weight at all.
But the whole thing here makes me wonder, what did happen to that Whalecow, that she turned out to be such a horrible and despicable "mother"? Did she claim one of the usual suspects yet?