You know, psychological is close to somatic, in other words our emotions are closely connected to what our body feels. You know why?
Basically our brain, the substratum for thinking and feeling is still the part of the body, and its proper functioning depends on how well the body provides it with oxygene, glucose, proteins and a number of other elements that serve as the fuel for brain functioning and the material for its development. Also body produces various hormones directing the functioning of brain. So our thinking abilities and states of mind obviously spring from the conditions and functioning of the body.
If we feed our bodies with some unnecessary substances or have a shortage of some vital nutrients apparently that leads to experiencing negative emotions and brain exhaustion and vice versa, if we provide our body with all the substances and elements needed for maintaining it and the brain well-functioning, we'll feel great and full of energy in whatever life