A basic text on biochemistry will educate you more than this "expert". You really should educate yourself properly instead of following random web sites that confirm your own biases.

Carbohydrates ARE converted to fat under normal dietary conditions, via insulin. If this metabolic process was "rare" as he states, then diabetics that require insulin injections wouldn't need them often.

I don't know where this "expert" is getting his information from, but it's a basic human biochemical reaction to form fat from blood glucose, via insulin.