Minecraft daily ration system?

I don't think you'll need commands for this actually.

What you could do is set of a daylight sensor with some redstone and dispensers. Every morning when the sun comes up, the sensor will activate the dispensers to drop the food you have placed inside them, then you can manually pick it up for daily rations. At night, the sensor shuts off, and then reactivates in the morning.

You'll probably need a couple of dispensers to do this, but it shouldn't be a problem.
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Another alternative would be to use the daylight sensor to power a command block to give the code /give [your name] (code for steak) (quantity). That would automatically give you a set amount of food every morning in Minecraft.