If you want crystal meth, take crystal meth.

Oh wait, maybe always doing what you want isn't actually that good of an idea.

If you want a straw man, have a straw man.

If I'm misrepresenting your point about following desires first and foremost, then please explain. You say "follow advice tailored to your specific situation", but you don't need to be a doctor or to know the specific situation to say crystal meth is a bad idea, so I'm not misrepresenting you there either.

This is reduction to the absurd, not a straw man.

We eat to live, but to live we must be happy. Eating what would make us unhappy is therefore contradictory to the purpose of eating. Eating must bring joy to life.

Therefore, we should eat what makes us happy, which is to say what we want.

The only counterargument here is to prioritize your body's immediate health needs, because not doing so (eg: not listening to doctor's orders) is to forfeit life which is contradictory to the purpose of eating.

So eat what you want, within the bounds of what your health allows.

This makes sense, but "prioritize not eating what you don't want" is, in a subtle but important way, a different piece of advice than "prioritize eating what you want". The first leads to moderation, the other to gluttony. I oppose the latter formulation.

And your solution is?

Beware of simple answers. Don't thoughtlessly follow your desires. Don't ignore others, but learn from them.