Night Eating Syndrome

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.

In a recent report of a collaborative effort involving behavioral and endocrine studies conducted in the United States and Norway, researchers shed new light on NES. The article, published in JAMA, suggests that NES – characterized by nightly binging to combat stress and insomnia, followed by morning-after bouts of anorexia – may be deeply rooted in stress-related hormonal imbalances.

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.

Therapy to increase the natural nocturnal rise in melatonin, reduce the body’s adrenal stress response and raise leptin levels or improve leptin sensitivity are options that may help these patients overcome the disorder. Another key may involve the availability of tryptophan, an important amino acid, in the body. More than 70% of the nighttime eating to combat anxiety involved binging on carbohydrates. These foods are believed to increase the amount of tryptophan available for conversion to serotonin, the calming neurotransmitter in the brain that promotes an overall sense of well-being and, in turn, converts to melatonin.

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.


Signs, symptoms & indicators of Night Eating Syndrome

Symptoms - Food - General  

Night eating

Risk factors for Night Eating Syndrome


Low Melatonin Level

Melatonin levels were found to be generally lower in patients with Night Eating Syndrome.



Nighttime eaters have elevated levels of the stress hormone cortisol during almost all hours of the day, suggesting that they suffer from the effects of chronic stress in their daily lives.

Night Eating Syndrome suggests the following may be present



Nighttime eaters have elevated levels of the stress hormone cortisol during almost all hours of the day, suggesting that they suffer from the effects of chronic stress in their daily lives.

Recommendations for Night Eating Syndrome

Amino Acid / Protein  

Tryptophan / 5 HTP

Taking Tryptophan or 5-HTP orally causes an increase of serotonin in the brain. It is proven that more than 70% of the nighttime eating is about carbohydrates – foods which are believed to increase the amount of tryptophan available for conversion to serotonin, the calming neurotransmitter in the brain.


Low Fat Diet

Mice that ate a high-fat diet gained weight and experienced a disruption in their circadian clocks, which regulate metabolic functions such as when they go to sleep, wake up and become hungry.

The disruption threw off the timing of the animals’ internal signals, including appetite control. As a result, the mice ate extra calories during the time when they would have otherwise been asleep or resting. For humans, this would be the equivalent of raiding the refrigerator in the middle of the night.

The high-fat diet and resulting weight gain also triggered diminished expression of genes that encode the clock in the brain and in peripheral tissues.

The findings suggest that changes in metabolic state that occur with obesity and diabetes affect not only circadian rhythms of behavior but also physiology.

Past studies have found that a misaligned body clock can throw off your metabolism, and increase your risk of obesity and diabetes.

This represents a “vicious loop,” according to researchers, because once weight is gained, your internal clock is disrupted, and a disrupted clock makes the original problem worse.

“Timing and metabolism evolved together and are almost a conjoined system,” said one of the study’s authors Joe Bass, M.D., assistant professor of medicine and neurobiology and physiology at Northwestern and head of the division of endocrinology and metabolism at ENH. “If we perturb the delicate balance between the two, we see deleterious effects.” [Cell Metabolism Nov. 2007, Vol 6, pp.414-421, 07]


Lab Tests/Rule-Outs  



Reading List

Overcoming Night Eating Syndrome: A Step-by-Step Guide to Breaking the Cycle by Dr Kelly C. Allison, Dr. Albert J. Stunkard and Sara L. Their.


Weak or unproven link
Strong or generally accepted link
Proven definite or direct link
May do some good
Likely to help
Highly recommended


Anorexia Nervosa

An eating disorder characterized by excess control - a morbid fear of obesity leads the sufferer to try and limit or reduce their weight by excessive dieting, exercising, vomiting, purging and use of diuretics. Sufferers are typically more than 15% below the average weight for their height/sex/age and typically have amenorrhea (if female) or low libido (if male). 1-2% of female teenagers are anorexic.


Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.


The only hormone secreted into the bloodstream by the pineal gland. The hormone appears to inhibit numerous endocrine functions, including the gonadotropic hormones. Research exists on the efficacy of melatonin in treating jet lag and certain sleep disorders. Dosages greater than l milligram have been associated with drowsiness, headaches, disturbances in sleep/wake cycles and is contraindicated in those who are on antidepressive medication. It also negatively influences insulin utilization.


Essential amino acid. Natural relaxant and sleep aid due to its precursor role in serotonin (a neurotransmitter) synthesis. Along with tyrosine, it is used in the treatment of addictions.

Amino Acid

An organic acid containing nitrogen chemical building blocks that aid in the production of protein in the body. Eight of the twenty-two known amino acids are considered "essential," and must be obtained from dietary sources because the body can not synthesize them.


Apprehension of danger, or dread, accompanied by nervous restlessness, tension, increased heart rate, and shortness of breath unrelated to a clearly identifiable stimulus.


The sugars and starches in food. Sugars are called simple carbohydrates and found in such foods as fruit and table sugar. Complex carbohydrates are composed of large numbers of sugar molecules joined together, and are found in grains, legumes, and vegetables like potatoes, squash, and corn.


A phenolic amine neurotransmitter (C10H12N2O) that is a powerful vasoconstrictor and is found especially in the brain, blood serum and gastric membranes of mammals. Considered essential for relaxation, sleep, and concentration.


Chemicals in the brain that aid in the transmission of nerve impulses. Various Neurotransmitters are responsible for different functions including controlling mood and muscle movement and inhibiting or causing the sensation of pain.


Usually Chronic illness: Illness extending over a long period of time.

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