Yes, it's fair, and No, it's not too extreme. I did something like that when my kids were teens. I was a single mom so I didn't have the husband/partner part. It turned out to be such a non-issue. Some thoughts in no particular order:

- The kids just liked having FOOD around that they liked so they weren't hungry and it tasted good. If I had cheese sticks, meat, nuts, and fruits, and veggies with dip, they honestly did not miss junky snacks. They were just HUNGRY especially after school because lunches were so rushed and lousy choices. In fact our house became a bit of after-school-snack central because I said they could eat after school and before dinner, but it had to be real food. And what happened was, my DD and her girl friends, made good sandwiches and snacks for my DS and his guy friends - practicing for superbowl parties I guess. It was expensive to provide real food but very interesting to watch sociologically!

- As I quit buying the bad old stuff I would ask them what they might like for next week. Both parties had to buy into the shopping list. Over time we came up with a new list of staples. Like I don't want to shock anyone with talk of potatoes - but Pik Nik brand shoestrings are like half saturated fat instead of "healthy" veg oil. Not bad as a transition thing.

- I was perfectly fine saying junk food was entertainment and it wasn't coming out of my grocery money. If they wanted it they could use their own allowances and keep it in their room. They each tried once or twice and never spent their money that way again - they much preferred buying Starbucks and movie tickets when out with friends. Junk food was not worth their money, why on earth mine?

- Surprisingly my DD told me she appreciated having non-junk good food always at home. It gave her the feeling of freedom when out and about - if she had junk outside, she knew she had a better baseline to come home to. or that if she had 75% good stuff at home, her indulgences in social life weren't so bad.

- Also surprisingly my DD told me she started to get horrified at how some families still eat. We had transitioned to dinners that were things like steak or salmon, veggies with ginger and garlic, and rosemary potatoes. Then she would go to a friend's house and they would have spaghetti and meatball casserole over mac and cheese. The contrast started to get startling.

I would do it again in a heartbeat with growing kids. Plus it can be a family identity team building thing - "we get a kick out of eating really well"