Hello there!

You know, I don’t think this sounds like a problem.
In fact, it may actually be an advantage.

Your body has become less accustomed to fatty, sugar-leaden foods, and as a result more sensitive.
A good example would be lactose intolerance. If someone reverts to lactose free milk, for perhaps, three months, and then goes back to their previous lactose-rich milk, they may well find themselves intolerant.
The same goes for you and your tingling tongue!

I would try not to worry about it. As a general rule, the body is a great pointer – if it tells you to avoid fat, sugar and other unhealthy foods, listen to it: it might well know best.

Good luck, and if in doubt, see your doctor. He or she might be able to find another unrelated cause, such as gingivitis or insulin sensitivity.
My advice to you would be to avoid foods that trigger your sensitivity, and see how you improve. Do this for three months – that is a good stretch of time for your body to adapt into – and if the problem has not improved, get a quick medical check.
It is probably absolutely nothing serious, if anything at all!

Best of luck, my friend.

– Skryfster