I never had much trouble managing hunger, even before unlocking any of the food upgrades. The basic plant slop is incredibly cheap and more than sufficient. I never saw much reason to make anything else but the power bar, as they cost far more valuable resources for no real benefit.
Honestly, hunger doesn't seem to serve much purpose now -- oxygen is by far the greater limiting factor on your ability to explore. Maybe you should make it so you can't make any food at all until you get the food upgrades, forcing you to rely entirely on scavenged fruit?