When habitual late-night eating overlaps with regular insomnia, a rare condition called Night Eating Syndrome (NES) is usually diagnosed.
NES is a condition that impacts only 1.5% of the population in the United States, but you’re more likely to have it if you’re obese or suffer from another eating disorder. Roughly 10% of obese individuals have NES.
A history of depression, anxiety and substance abuse is also more common in people with NES. It differs from binge eating disorder (BED) in that with BED, you’re more likely to eat a lot at a single sitting. With NES, you’re likely eat smaller amounts throughout the night before going to bed.
What are symptoms of Night Eating Syndrome?
These symptoms are commonly linked to NES:
- Waking up at night to eat at least twice a week.
- Trouble falling or staying asleep (insomnia) four to five nights a week.
- Regularly eating more than 25% of their daily calories between dinner and sleep.
- A lack of appetite on most mornings.
- A depressed mood that worsens at night.
What causes Night Eating Syndrome?
NES is categorized as an eating disorder that combines overeating at night with sleep problems. Per the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR), it is considered an Other Specified Feeding and Eating Disorder, otherwise known as "OSFED."
An OSFED is an eating or feeding disturbance that causes clinically significant distress or impairment but does not meet the full criteria for any of the disorders in this diagnostic class. In addition to NES, this might include (but is not limited to):
- Atypical Anorexia Nervosa
- Bulimia Nervosa, Binge Eating Disorder or limited duration
- Purging disorder
While there’s no consensus take among health care providers as to the cause, some researchers have characterized NES as a delayed circadian pattern of food intake. In other words, if you NES, you have a malfunctioning internal clock. This can lead to a hormone release that make you feel hungry and alert at night instead of during the day. Instead of eating one big meal around dinner time, many with NES eat smaller meals and snacks throughout the night.
A recent 2020 study found that participants who prefer to go to bed later and sleep deeper into the morning were more likely to have NES. Other studies link NES to a delayed release of melatonin, a sleep-promoting hormone. Additionally, people with NES have recorded higher scores for depression and low self-esteem than those without the condition.
Some research has found a possible link between NES and genetics. There’s a gene called PER1 that’s thought to play a role in controlling your biological clock. Scientists believe a defect in the PER1 gene could cause NES, but more research is needed.
How is Night Eating Syndrome diagnosed and treated?
To be diagnosed with NES, an individual must overeat at night for at least three month. Health care providers typically diagnose NES by first conducting a detailed questionnaire with a patient about their eating and sleeping habits. A sleep study known as a polysomnography may also be recommended. This is a test that studies brain waves, breathing rates and blood oxygen levels to find possible abnormal sleeping patterns.
Treatments options can include antidepressant medication, which has shown across several small studies to decrease night eating and improve mood and quality of life. Cognitive behavioral therapy is another option. These treatment methods depend on your primary care provider’s (PCP) advice. Melatonin or substances that boost melatonin for NES may also help, though you should talk to your PCP about this, too, before trying it. Though considered relatively safe, melatonin is not approved by the Food and Drug Administration (FDA).
How can I prevent Night Eating Syndrome?
Since it is such a rare condition, many people can avoid NES by practicing the same healthy habits you should be mindful of anyway. This includes:
- Good sleep hygiene: Keeping your bedroom at a comfortable temperature, going to sleep and waking up at the same times each day, and avoiding caffeine and electronics before bedtime.
- Eating mostly healthy foods: People with NES typically crave foods that are high in calories, carbohydrates and sugar. Keep the junk food and processed food in your house to a minimum.
- Managing your mental health: Meditation can be helpful; some studies link mindfulness meditation with improved sleep quality and less insomnia. Journaling is another helpful option. You may also want to explore therapy or counseling with a mental health professional, if you’re not in therapy already.
Staying physically active: Regular exercise during the day has been proven to help people fall asleep quickly while improving sleep quality.
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