Quoting Destiel:" That's exactly right, I read in a book about 12 years ago that it was the quickest way to lose weight ... [snip!] ... want him doing this, especially since this was supposed to be a family thing and I can't have my 21 month old eating like that."
My degree is in nutrition and i have worked with people trying to lose weight extensively.
It's REALLY hard to know if this is a good approach without further details but, here is my 2 cents:
The "yuck diet" may be good for a short time. When you are truly morbidly obese, sometimes you need a "shake up" to sever the bad habits, get immediate results and give yourself the motivation to start eating in a healthy way.
Food a a HUGE part of our culture. Persoanlly, much of my day revolves around it as I'm an awesome cook and "foodie" Since you both have weight problems, i'd say that it is a key part of who you are and what you do. That said, I think what is best is to have something that works for the long-term and in allsituations (not just at home with access to the yuck).
Perhaps the dietitian plans on following up with your SO to make recommendations after a short time on "the yuck?"
I'm not sure what you have in australia, but here we have Weight Watchers and it is excellent for helping teach you healthy eating and long-term success.