A friend of mine (with an autistic child) explained it as:
If you give your kid a strawberry - even within the punnet the tastes and textures will vary - even mid summer some will be unpleasantly tart.
If I make a sandwich it will be mildly different one day to the next, depending on the freshness of the items I put in, the brand of the ham, the spread, the bread.
But junk food will ALWAYS BE THE SAME. If surprise and novelty is an issue for you/your child, then eating food like that removes so much stress for everyone involved. Yes it isn't healthy, but the meal gets eaten and no one cries.
But say, one goes to get McDonald's nuggets and lightly and secretly messes up with it (adds a bit of lime one day, vinegar another, etc.) before giving it to the obsessed child. Wouldn't that remove the "always the same" aspect and thus decreasing the appeal of junk food over other foods?
Also I'm sure cheese, avocado, a carrot, zucchini or pumpkin from the supermarket are going to taste extremely similar across the months unless they are hyper tasters (in that case they'd definitely notice a change in taste across nuggets).
The difference between fresh McDonald’s nuggets and ones that have sat in the UHC/production bin for half an hour is night and day though, and that’s just the variance officially allowed by McDonald’s - don’t get me started on double-fried nuggets!
Have you tried ordering them "fresh"? It takes a few minutes longer, some cashiers won't know what that means, and they might not do it if its late and they're closing up, but I've always ordered "fresh" nuggets and french fries that are made to order instead of pulled from the baskets. Explaining that it's a food sensitivity issue will almost certainly get most of them to comply.
It works at all the fast food places for fried items, as far as I can remember (except Seattle's Dick's).
If you give your kid a strawberry - even within the punnet the tastes and textures will vary - even mid summer some will be unpleasantly tart.
If I make a sandwich it will be mildly different one day to the next, depending on the freshness of the items I put in, the brand of the ham, the spread, the bread.
But junk food will ALWAYS BE THE SAME. If surprise and novelty is an issue for you/your child, then eating food like that removes so much stress for everyone involved. Yes it isn't healthy, but the meal gets eaten and no one cries.