As much as I personally enjoy having to farm for multiple types of food, this suggestion is a straight downgrade to the current hunger system. It'd just make hunger management more tedious. Give it some kind of benefit system. Maybe eating a food (possibly anything from the whole category) you haven't eaten much of recently gives it a massive saturation boost? Maybe it gives off some kind of new potion effect? Nobody will want to support it if it's only downsides. The hunger bar itself had benefits such as enabling health regeneration and sprinting.
And please, let the food fatigues be hidden mechanics, not potion effects. Potion effects can be cleared with a simple bucket of milk (this even applies to things like Bad Omen and Hero of the Village), and I don't want my screen cluttered with Fatigue timers every time I open my inventory.
I disagree with your comment about nobody wanting to support it if it is only "downsides". If you read my post further up the thread, I already expressed support.
I support your idea of keeping the fatigue a hidden mechanic as opposed to being a potion effect.
Consider the "This suggestion only brings downsides" argument. This suggestion may bring objective downsides to Minecraft regarding Minecraft's current system, but Minecraft's current system is why we are suggesting a change in the first place.
The current system could use rework because it is out of balance. Once balance is brought between the food items, the new system may be considered a "downside" from the old system in regards to immediate player benefit, but the main point of the suggestion is to rework the system with little to no concern for matching it's standards with the current system. Whether or not this suggestion makes Minecraft easier or harder in the long run is not as important as bringing balance to the food items.
If I were in Mojang, I would bring balance by setting new standards, and then refine difficultly based on the new system and how it relates to other in-game systems, as opposed to matching difficulty with the old hunger system. Forget the old system, it was broken to begin with, and too easy in my opinion.
I am not opposed to adding "upsides", but this "downside" suggestion alone does not "just make the hunger system more tedious"; it sets new standards that fix the current unbalanced hunger system. Of course, what is tedious is subjective; for me this suggestion would make the hunger system more fun.
In regards to the overall Minecraft survival experience, this system is a straight upgrade from the current hunger system. It needs to be refined.