Evolutionary Lifestyle & Stimuli

What were the stimuli to which early humans were subjected to? By understanding this, we can try and provide them to our bodies even if they are not part of our current modern lifestyle.

The main characteristic of the environment in which all early homo species evolved in (which was true up until around 120 years ago) was energy scarcity. The fact that energy was rare shaped our biology much more than any other characteristic. This shows in two ways:

  • the body conserves energy each time it can afford it (we’re “naturally lazy”)
  • the body gorges on calories each time it can find them easily enough (natural appeal for fats/carbohydrates, and tendency to store fat as reserves)

Let’s see some details of their lifestyle then, across three areas: physical, nutritional and environmental.

Physical stimuli

Any lifestyle makes the body go through certain physical activities on a daily basis. You walk, move, sit, stand, manipulate objects, etc. The hunter-gatherer lifestyle was characterized by:

  • hunting, gathering: high volume of daily walking (15-20km), at times loaded with weight to carry, and occasional runs and sprints, good amount of tree climbing for both activities.
  • avoiding predators: sudden moves to evade predators, sprinting and quick climbing up trees and rocks
  • building shelter: weight lifting (small to high loads) and load manipulation
  • tending to the campsite: high degree of ground movements, object manipulation with the hands, loading and carrying small weights
  • scouting for new campsites: long walks without weights
  • moving between campsites: long but slow walks with weights

To summarize:

  • high volume of daily walking, part of it loaded with weight
  • low but daily volume of weight lifting and manipulation, occasional high loads
  • very high baseline of total physical movement volume daily
  • very high diversity of movements

Nutritional

There wasn’t one diet specific to the early homo sapiens. Rather, there were several according to their regions. But there were commonalities that we can use to design a modern optimized diet:

  • very high volume of fibers: fruits and root vegetables consumed as the bulk of the diet were wild, and very fibrous (which provided another physical stimuli: they spent several hours a day chewing).
  • very low volume of carbohydrates in all its forms (simple or complex, fructose, glucose, starches, etc.): wild fruits were not sweet like today’s domesticated fruits are, and root vegetables like sweet potatoes were not as loaded in starches either. And since they needed to chew each bite a long time, they couldn’t absorb much sugar in any case.
  • it did contained meat/fish, with the whole bodies being consumed, so incorporating all the fat, all the nutrition from organ parts, etc.: one dominant theory regarding the emergence of the early homo species is that they managed to get an energy surplus through meat consumption, which afforded them the energy to develop bigger brains.

Environmental

The environmental area groups all other stimuli that are not either Physical or Nutritional, but impact our health.

Some salient stimuli of a hunter-gatherer lifestyle that differs from our current western lifestyle:

  • sleep: no chronic sleep deprivation, but more complex sleep patterns and the occasional stretch of days with little sleep
  • child-rearing as a group: children were most probably raised in common within the group, which also means taking turns caring for them at night, etc.
  • no chronic daily stress: acute stress for some periods but chronic and long-term stress was probably less present than it is today