Is that true? Wikipedia says (at least in the USA) you need 1200 hours of supervised and practical experience and you have to have a bachelor's degree. Following their source link, it looks like you have to apply for the licensing test 12 months before actually taking it, too.

https://en.wikipedia.org/wiki/Dietitian#United_States

--edit: I think you might be talking about a nutritionist (https://en.wikipedia.org/wiki/Nutritionist) which is not regulated in any way and is not a medical job. These are the people who will talk to you about essential oils and homeopathy and Herbalife.