Many modern conveniences strip some of the mental(including mood) and physical health benefits of "roughing it", which used to be done out of necessity.
A few examples:
1. Occasional fasting was normal throughout human history due to intermittent food shortages(drought, hunters couldn't find prey, etc...).
Benefits:
"Ketones have also been shown to reduce cellular damage and cell death in neurons and can also reduce inflammation in other cell types."
"When you are fasting, ketone bodies generated by your liver partly replace glucose as fuel for your brain as well as other organs. This ketone usage by your brain is one of the reasons that fasting is often claimed
to promote mental clarity and positive mood – ketones produce less inflammatory products as they are being metabolized than does glucose, and they can even kick-start production of the brain growth factor
BDNF"
With 3 day fasting, the body goes into a state of autophagy:
"Autophagy is the body's way of cleaning out damaged cells, in order to regenerate newer, healthier cells, according to Priya Khorana, PhD, in nutrition education from Columbia University. “Auto” means self and
“phagy” means eat. So the literal meaning of autophagy is “self-eating.”
2. Cold showers/bathing. Humans didn't always heat their water.
Benefits:
"ice baths and showers increase the release of norepinephrine, a hormone that works to calm you down, to the blood. It also affects your mood, vigilance, focus, and attention.
Norepinephrine can rise 200-300% with cold immersion near 0 celsius for 20 seconds / 3 times a week. Norepinephrine reduces inflammation through the inhibition of inflammatory cytokines including TNF-alpha
(tumor necrosis factor alpha), a molecule involved in almost every human disease from type 2 diabetes to cancer"
3. Humans had natural diets historically.
Modern diets can negatively affect gut bacteria. Serotonin(associated with anti-depressants) is produced in the brain and intestines.
"In fact, the gut contains the vast majority of the serotonin in our body. Serotonin, or 5-hydroxytryptamine, is produced by the enterochromaffin (EC) cells lining the digestive tract."
4. On average, modern humans take in less sun than their ancestors.
Mind and body benefits. Easily researched.
5. On average, humans got much more exercise. Obvious mind and body benefits.
etc, etc....
How many have good natural diets, fast, take cold showers, get enough sun, enough exercise, especially cardiovascular.....