Depends (as always in life)

If i'm fighting a mob that is barely in range of my abilities, say a blucker parry vs lox, having those extra 5-10 hp might make a big impact on amount of stagger recieved. So eat as soon as possible.
Same with climbing mountains without cold resistance, or doing very stamina intensive work like digging/farming - the more max stamina you have further you go and the quicker the regen.

But otherwise if you remember to actually eat before it gets too low, its not bad letting it go down. HP/s is another very important stat that does not change with time. So when i know i wont get staggered or be pressed with stamina usage, i wait til last minutes to eat.


Other considerations: 1) food juggling, eating early allows you to pick different food flexibly, while if you refresh last minute and then suddenly need different food, its wait time, or difficult fight.
And 2) rest time, eat hp food when resting (camping) to get full regen out (useful in caves ie)

Thats the need part of the equation... As for supply i always swim in sausages so the main reason to delay refreshing them is only to be on the same timer as wolf jerky.
And then honey, gets eaten on cooldown.