Sustainable food is steady work but not all time consuming.

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).