I saw the nutty professor years ago, so correct me if I remember the details wrong. Doesn’t he take a ‘thinning’ serum to make him go from overweight to skinny? And then the serum wears off and he gets big again? Well if this serum did exist, the inventor would make so much money!! I have no idea what the film makers pretended the serum was made of? Perhaps a chemical that can dissolve fat, turning it from a solid to a gas or liquid? Or maybe only temporarily dissolves it, that could explain how the professor gets fat again. Its all just guess work 🙂 And no, I don’t think it was a good idea. What the professor needs is a salad and a 5k run, not magical serum!!
Since the fat seems to go away only to reappear later when the drug wears off it seems like the fat didnt dissappear (why would it come back then?). We can also rule out the fact that the fat was srunk but still there because even if he was thinner he would have the same mass. This would mean he would have as much weight to carry around making walking etc just as difficult as before. We can rule this out based on the energetic antics of the nutty professor alter ego!
The only possibel conclusion I can come up with is some sort of fat targating wormholes that temperarly transport the fat to antother dimension only to transport it back when the drug wears off. I wouldnt however hold my breath for such a drug in the future!