The stress response, which maintains allostasis, is comprised
of a cascade of adaptive responses originating in the central
nervous system as well as in the periphery. It leads to dramatic but
time-limited physiological, psychological and behavioral changes
that affect appetite, metabolism and feeding behavior [12]. The
acute stress response includes behavioral, autonomic and
endocrinological changes promoting heightened vigilance, decreased
libido, increased heart rate and blood pressure, and a
redirection of blood flow to fuel the muscles, heart and the brain
[13]. Stressors evolutionarily required an immediate fight or
flight, so energy is diverted to the brain and muscle tissue to save
life. Under such circumstances energy spent on housekeeping
activities–such as food intake, digestion and reproduction–would
be potentially life threatening [14]. Thus, part of the stereotypical
stress response includes suppression of appetite and food intake.
Given that, the association of weight gain with the stress response
seems counterintuitive. Below we try to elucidate potential
explanations for the stress-eating paradox, the fact that stress can
lead to both under-and over-eating. Little is known about what
determines direction of eating, although it is clear that the
hypothalamic pituitary adrenal (HPA) axis is at least one of the
central players in explaining changes, both undereating and
overeating due to stress.