In terms of the content of this paragraph, you seem to be moving away from your main topic. Your main topic is the portrayal of weight issues and food issues. Parts of this paragraph do not address this. In particular, the sentences about Sally’s tomato plant and Tommy hiring a private eye do not appear to have anything to do with issues of weight and food. You should either change your essay to be about relationship issues more generally (even then, Sally’s tomato plant does not seem to fit here) or you should remove these sentences.
As for the rest of it, I suggest changing the second sentence. “Bemusement” is perhaps not the right words. You might just say “After Dick realizes he has gained so much weight…” If you are going to start the sentence in the present tense, you should continue in that tense. Say “he begins dieting…” Finally, “filling” should not be capitalized.
The major issue to resolve here, though, is the issue of content. If this essay is really mainly about food, you need to remove the sentences that are not clearly connected to that topic.