What it is
A self-paced certification covering nutrition science and, more usefully, a coaching method for changing what people eat — habit sequencing, client conversations, and working within scope.
Best for
Trainers who keep getting nutrition questions and currently answer them from instinct. The coaching half is what justifies the price; the science half you could assemble yourself.
Watch out for
It is a serious time and money commitment, and a certification is not a licence — what a non-dietitian may advise varies by country and by state. Check your local scope of practice before you buy.