Sure, I think your example is ironic:

a situation in which something which was intended to have a particular result has the opposite or a very different result

Source: Cambridge

Ironies can also be funny. In your case, one might think that a person who is hungry can pick up a bag of food on the floor and feed themselves. But in your story, the opposite happened: the fat person ended up dying of starvation, which is definitely funny to me. (Yay for dark humor!)

Sure, I think your example is ironic:

a situation in which something which was intended to have a particular result has the opposite or a very different result

Source: Cambridge

Ironies can also be funny. In your case, one might think that a person who is hungry can pick up a bag of food on the floor and feed themselves. But in your story, the opposite happened: the fat person ended up dying of starvation. (This can be a kind of dark humor!)