January 2010 Issue

Night Eating Syndrome
By Cathy Leman, MA, RD, LD
Today’s Dietitian
Vol. 12 No. 1 P. 8

If you’re unfamiliar with night eating syndrome (NES), you may question whether it even exists. I know I did. A solid sleeper, I couldn’t imagine heading for the kitchen during the night, let alone actually ingesting food. But I started to hear more about night eating, and then clients striving to lose weight began to share details of their own struggles—only they didn’t call it NES. A bit ashamedly, they shared that they routinely got up to eat during the night, often didn’t remember eating, and had to eat in order to get back to sleep. This called for further investigation. I wanted to find out more about this phenomenon and what, if anything, I could do to help.

Definition, Prevalence, and Characteristics
NES is characterized by a lack of appetite in the morning, overeating at night, and waking to eat throughout the night.1 Seen as a delay in the circadian rhythm of food intake while retaining a normal sleep-wake cycle, it is defined by two core criteria: the ingestion of at least 25% of daily calories after supper and/or awakening to eat at least three times per week.2 First identified some 50 years ago, yet only recently familiar to healthcare professionals and the public, NES can disrupt lives and damage health.

Experts estimate that 1.1% to 1.5% of the general population, 6% to 16% of patients in weight-reduction programs, and 8% to 42% of bariatric surgery candidates experience NES. The prevalence of NES appears to be similar across genders or is slightly more prevalent in men.3

One of my male clients has an unhealthy lipid profile, including triglycerides in the 800s and a body mass index of 35. At least five nights per week, he falls asleep easily, only to wake one hour later and head to the kitchen for something to eat, unable to get back to sleep until he does so. As the stress in his life has escalated in recent months, so have his NES behaviors.

Alicia* is a young woman in recovery due to an eating disorder. Initially she experienced behaviors that paralleled those of my other NES clients, but she progressed from eating only in the kitchen to keeping food in her room and then ultimately to stashing food next to her on her twin bed. When she woke up, she would eat in an almost dreamlike state until she fell back to sleep.

Possible Causes
Single photon emission computed tomography has shown significant elevation of serotonin transporters in the midbrain of night eaters. Elevations in serotonin transporter levels lead to decreased postsynaptic serotonin transmission and should impair circadian rhythms and satiety.3 While elevated serotonin transporters contribute to the brain chemistry component, depression, anxiety, hostility, and stress are strongly implicated in NES. These negative emotions, merged with the guilt and embarrassment associated with such unconventional eating patterns, form a perfect psychological storm that exacerbates the problem.

Which comes first: psychological issues that trigger this disordered eating pattern or disordered eating patterns that trigger depression and anxiety? According to Overcoming Night Eating Syndrome: A Step-by-Step Guide to Breaking the Cycle, many people report that their night eating began during a period of stress. Though Alicia was never “officially diagnosed” with NES, through eating disorder counseling, she learned that her night eating behaviors were linked to her high anxiety and the comfort she received from eating.

For others, the cause may not be clear. Research suggests that heredity may offer a clue, so recommending that clients delve into their family history may afford surprising insights. Additionally, an imbalance in the hormonal relationship that regulates sleep and stress levels may also affect patterns of eating and sleeping.2

Identification and Recognition
NES is not always recognized by health professionals, is still relatively new to healthcare providers within all disciplines, and is often overlooked. The May/June 2009 issue of the European Eating Disorders Review highlights a study in which patients reported low recognition and high levels of dismissal of NES by their doctors. Frequently, the signs and symptoms may be mistaken for other conditions or identified simply as bad habits.

The 14-item Night Eating Questionnaire is a reliable method for identifying NES. Remember that not every night eater has all of the signs of NES. For clients whom you suspect may be experiencing the syndrome, the questionnaire can help them initiate a discussion with a physician or therapist and serves as validation of their concerns. Additionally, a study published in the January 2008 issue of Eating Behaviors found the Night Eating Questionnaire to be an efficient, valid measure of NES severity.

Treatment
Just as night eating is recognizable, it is also treatable.4 Alicia’s RD/therapist team first worked to get the food out of her room and then to decrease the number of calories she consumed when she did experience a night eating episode. Alicia no longer struggles with NES. “Now, whenever I wake up in the middle of the night, I never even think about eating,” she says.

But not every individual with NES is as fortunate. The European Eating Disorders Review study also reports that most patients (61% of the 103 polled) were “not at all satisfied” with their doctor’s treatment of NES.

Once NES has been identified, there are a variety of treatment methodologies available. Encouraging the client to increase physical activity and follow a consistent exercise program, maintain a food diary, and keep records of bedtimes, awakening times, and thoughts about night eating is a good first step. A sleep study can also help identify other disruptive sleep conditions, such as sleep apnea, restless leg syndrome, snoring, or night terrors. Counseling or psychotherapy that employs therapeutic approaches such as cognitive-behavioral, interpersonal, or psychodynamic therapy may be critical for clients with high levels of stress, depression, or anxiety.1,5

Research on the benefit of medications for NES is in its early stages; however, encouraging studies support the use of sertraline (Zoloft), a selective serotonin reuptake inhibitor, as a well-tolerated drug that offers effective treatment.6 

Providing Affirmation, Guidance, and Help
Nutrition professionals routinely screen for nighttime snacking but may not consider overnight eating. For clients who are struggling but embarrassed to mention the behavior, your identification and affirmation of NES can be liberating. For bewildered clients who awaken to remnants of food and empty containers, the discussion can provide relief; they’ll appreciate your insight and helpful suggestions.

If the Night Eating Questionnaire results suggest the presence of NES, discuss the previously described methodologies with your client. Consult Overcoming Night Eating Syndrome for journaling exercises and guidance in working with therapists, as well as engaging the help of roommates and family members.

— Cathy Leman, MA, RD, LD, is a nutrition therapist, freelance writer, speaker, and nutrition consultant. She is the author of two booklets, Nutrition at Work and Eat Healthy, Live Healthy, and her passion is teaching people how to balance food and fitness for life.

* Name changed to protect identity

References
1. Allison KC, Stunkard AJ, Thier SL. Overcoming Night Eating Syndrome: A Step-By-Step Guide to Breaking the Cycle. Oakland, Calif.: New Harbinger Publications; 2004.

2. Goel N, Stunkard AJ, Rogers NL, et al. Circadian rhythm profiles in women with night eating syndrome. J Biol Rhythms. 2009;24(1):85-94.

3. Stunkard AJ, Allison KC, Lundgren J. Issues for DSM-V: Night eating syndrome. Am J Psychiatry. 2008;165(4):424.

4. Allison KC, Stunkard AJ. Treatment of night eating syndrome. In: CM Grilo, JE Mitchell, eds. Treatment of Eating Disorders. New York: Guilford; in press.

5. Allison KC, Stunkard AJ.  Self-help for night eating syndrome. In: Latner JD, Wilson GT, eds. Self-Help Approaches for Obesity and Eating Disorders: Research and Practice. New York: Guilford Press; 2007: 310-324.

6. O'Reardon JP, Allison KC, Martino NS, et al. A randomized, placebo-controlled trial of sertraline in the treatment of night eating syndrome. Am J Psychiatry. 2006;163(5):893-898.