Healthy appetites are desirable! It's associated with being strong and healthy.

[which sungki knows isn't actually the case. jin is plenty strong and healthy.]

It could also be taken as an insult to my mother's cooking, but Jin would never do that.

[he'll be far more likely to force himself for the sake of politeness, which sungki worries about just as much.]

I'm sort of the same. I feel like I've done so much these past months! But I know that compared to most others, it's not as much.