100x100 meters is a lot of meters to be "garden farming", it's not a hobby anymore but a part-time job.
It's way more efficient for everybody to divide labor this way than to have each household be its own independent and self-sustaining system.
As my econ prof loved to say all models of the world dont assume there is mindlessly ambitious J P Morgan out there. And have nothing interesting to say about what to do about him.
Drop it by 2 orders of magnitude (10mx10m) and you are looking at 250kg /year. Which sounds like a reasonable amount both for a large garden and human consumption.
This article also reports that Niedersachsen potato fields (large state in northern Germany) produce an average of 45,000 kg/hectare, or about 18,000 kg/acre.
Potatoes alone take 60 to 90 days to grow (weather and varieties) and 'only' take up two to three days of full work (at most) per bed per crop (split the above into (say) three or four rotating beds).
The work is to turn and fork grown potatoes out, and prepping | weeding soil at same time, and then (same time) working new potato cuttings with eyes back in - then cleaning and storing - as potatoes are consumed bits that have budding eyes can be cut out and set aside for planting next time.
If you've got a spare back acre you can pretty much swap gym time for garden time and stay active, healthy, and mostly eat food you grow yourself (location dependant).
His back's fine and he spent a decade on shearing teams.
Work steady, smarter not harder.