You're lying in bed, and you can't sleep. If you think a little midnight snack might help to "soothe" your nerves, perhaps you should think again. While an occasional midnight raid on the refrigerator poses no threat to health for most of us, as a habitual pattern to combat sleeplessness, Night Eating Syndrome (NES) can play a powerful and destructive cyclical role in individuals battling obesity, affecting as many as one quarter of severely obese individuals.
Researchers from the Weight and Eating Disorders Program at the Department of Psychiatry of the University of Pennsylvania School of Medicine evaluated 10 individuals with NES. These individuals consumed over 50% of their food calories after 6 p.m. In addition, their sleeping and mood patterns differed greatly from controls, with mood falling steadily after 4 p.m., and nightly awakenings averaging 3.6 times per night.
Looking for possible biochemical triggers underlying this pattern, scientists from the Clinical Research Department and the Laboratory of Gastroenterology of the University Hospital in Tromso, Norway examined the hormone activity of NES patients (12 night eaters and 21 controls) over the complete light-dark cycle. They found that the night eaters – both normal and overweight – had significantly lower melatonin levels during the night than did the controls. Since melatonin levels normally rise at night to induce and sustain sleep, this may explain why NES patients wake up more frequently at night.
NES has been linked to hormone imbalances; high cortisol, low melatonin and leptin may make things worse. Leptin, the "hunger hormone" which rises at night to suppress appetite, was also lower in the NES patients, partly explaining their nocturnal food cravings. This "distinctive neuroendocrine pattern" in individuals with NES may provide the key to more successful treatment, said the researchers.
NOTE: Addressing hormonal and biochemical imbalances in patients with chronic eating and mood disorders can be crucial for uncovering fundamental causes and contributing factors that underlie cyclical, habitual patterns of insomnia, overeating, and depression.
Melatonin levels were found to be generally lower in patients with Night Eating Syndrome.