Why do we tire of some foods/drinks, and not others?

Why do we tire of some foods and drinks that we used to love, and not others? Here’s an example:

I always loved salmon. Fried, grilled, broiled, poached, made into patties, etc. There’s no way to prepare salmon that I haven’t loved. A couple years ago I started a low-carb diet, and discovered that salmon is one of the healthiest foods available, especially for it’s Omega-3 oils. So I started eating it 3-4 times a week.

After several months of this, I noticed that my taste for it was diminishing, and I was eating it only 1-2 times a week. After a while, I got to the point that I no longer liked it at all; in fact just a taste or smell of salmon would turn my stomach. That was last year, and I’ve gone about a year without any salmon at all.

Last night I tried salmon again, and had to literally force myself to eat it. I thought that my aversion to it would disappear after a year of abstinence, but no, the aversion is even stronger now.

I’ve noticed the exact same phenomenon regarding flavors of soda (pop) that I used to like, and now can’t stand. But on the other hand there are foods that I’ve eaten regularly yet my taste for them hasn’t diminished at all. For example, just about all fruits and vegetables, peanut butter, poultry and red meat.

So what’s going on here? Why do I develop a seemingly permanent aversion to some foods/drinks and not others? And how can I restore my former enjoyment of them?