"The intake of sweets may either act on similar neurochemical substrates to those affected by light or provide a behavioral marker for individuals susceptible to light response."
"As part of their winter depressions many SAD patients suffer from a reversible
form of obesity."
"Humans, however, naturally increase the length of their photoperiod by the use of
artificial lighting. If the seasonal changes in eating and weight described above are
influenced by photoperiod , how is it that they persist despite the use of artificial
lighting? The first clue to resolving this paradox came from the observation of Lewy and
colleagues, that whereas the nocturnal secretion of melatonin by the pineal gland could be
suppressed by artificial light in animals, it required light of far higher intensity (2500
lux) to suppress nocturnal melatonin secretion in humans. It was this finding that
inspired the treatment of patients with SAD by extending their winter photoperiod with
bright artificial light."