What is night eating syndrome?

Night eating syndrome( NES) is an eating disorder characterised by the consumption of excessive food in the evenings or at night. Overeating after dinner, midnight cravings for food, or frequent nighttime waking for food all contribute to NES. It generally occurs in the obese population,¹ in the age of teens to late twenties, undergoing or looking to undergo treatment for weight loss.² It is common in men and women equally and can be long-lasting, with increased chances of relapse with stress.³

Causes

The exact cause of the NES is unknown. 

• Hereditary - studies have shown that it could be inherited from parents. Children of parents with NES syndrome are more likely to have this eating disorder⁴
• Psychological conditions - stress and depression can also lead to NES.⁵ Childhood trauma, adverse life events, rejections, mental health disorders like depression
• Physiological causes - hormonal imbalances, such as Ghrelin or leptin imbalance, lead to hunger cues, sleep disturbances, and insomnia, all of which contribute to night eating syndrome
• Environmental and lifestyle causes - extreme dieting or severe malnutrition can lead to hunger pangs at night. Lifestyle stress, such as societal pressure, job stress, or performance stress, can also cause night eating habits

Telltale symptoms

3 or more of the following symptoms are seen in people with NEM:

• Missing breakfast 
• Urge to eat between dinner and sleep⁶
• Difficulty with sleep at night, waking up often
• The belief that one should eat before sleep
• Feeling low or depressed at night, feeling of guilt and shame⁷

Another criterion for NES is over intake of food, 25% more than the daily calorie intake after dinner and waking up at night, twice or more throughout the week for food.⁸

How is stress and eating connected?

There are 2 components of eating:

• Homeostatic eating - where food is taken for energy balance
• Hedonic eating - where food is eaten for pleasure and feels rewarding to the taste buds

Stress can simultaneously drive both components by reducing the calorie intake and shifting to hedonic eating, like salty, sugary, and palatable food, which are high in calories.

There is a stress system in normal human beings that maintains the homeostatic balance in resting and stress states. It is called hypothalamus pituitary axis(HPA), the hypothalamus in the brain releases Corticotropin releasing hormone(CRH), which stimulates the pituitary gland in the brain to release Adrenocorticotropic hormone(ACTH), which then causes the release of cortisol( a stress hormone) from adrenal gland of the body. Increased cortisol level tends to suppress the hypothalamus and maintain a homeostatic balance under normal conditions. This feedback loop balances the stress response.⁹

In people with eating disorders, an increase in the HPA axis is seen. Stress that is related to reduced calorie intake (to lose weight), binge eating at night, and frequently waking up from sleep, activates the HPA axis, lowers the cortisol response to CRH, thus leading to excessive cortisol production.⁹ This encourages hedonic eating habits, which counteract stress.

Melatonin hormones that work to control the body's sleep cycle. During disturbed sleep or stress, this circadian rhythm is disrupted due to reduced melatonin production, which directly affects the HPA axis. The quality of sleep influences cortisol stress responsiveness.⁹

Ghrelin, leptin, and insulin are appetite-related hormones. Stress induces a shift in Ghrelin’s function from homeostatic eating to increased hedonic eating, motivation to have comfort, starch-rich food as a reward.¹⁰

Insulin and Leptin are hormones that work synergistically with cortisol to increase fat deposition. In obese individuals, increased insulin production results in brain activation in stress and reward motivation pathways, and also increases the desire for high-calorie food.¹⁰

Psychological link between stress and NES

Studies have shown that university students tend to have body image concerns, sleep disturbances, anxiety, and performance stress, which leads to NES. Severe mood disorders like depression, ADHD, and addictive behaviour can cause impulsivity and exaggerated emotional eating as well.¹¹

It is often believed that eating is a precursor to sleep and hence, one must eat to initiate or return to sleep.¹¹ Poor coping strategies like self blame, self harm, substance abuse, psychopathologies like emotional eating (eating in presence of a negative emotion), external eating (eating in the presence of food) and food addiction which is when certain foods cause addiction-like behavioural responses, overeating may represent an addicted behaviour and has been linked with NES.¹²

Effect of night eating on mental and physical health

Studies on night shift workers with irregular eating habits and increased calorie intake at night show adverse effects on their health, such as obesity, weight gain, and impaired kidney and heart function.¹³ It is still unclear whether obesity is the cause or consequence of night eating syndrome, but studies have shown that NES is prevalent in those attempting to lose weight and also acts as a precursor to obesity in non-obese people with weight maintenance behaviour.¹³

Studies have shown that high emotional eating occurs in students with stress and anxiety.¹² Stress overactivates the HPA axis and is a precursor to NES. ⁹ Fat and carbohydrate-rich snacks act as a comfort food to cope with anxiety and stress. Emotional eaters with NES experience poor sleep quality and daytime dysfunction.¹⁴

This further leads to depression and low self-esteem.¹⁵ Plausible causes of it are reduced melatonin and leptin hormones and increased cortisol levels, which tend to affect sleeping habits and increase the odds of depression and depressive symptoms in night eating disorders.¹⁵

Treatment and intervention strategies

The DSM-5, or Diagnostic and Statistical Manual of Mental Disorders, provides criteria to diagnose NES.¹⁶ These include:

• Consuming more than 25% of daily calories after dinner or during nighttime awakenings
• People with NES are typically aware of their eating and will remember it, unlike other sleep-related eating disorders, where the person is unaware of their eating habits

Holistic treatment approach 

• One-on-one therapy - sharing personal experiences
• Group therapy - sharing experiences with others in the same boat as you are helps in realising personal struggles and strengths
• Cognitive behavioural therapy- starts with self-monitoring behaviour, making a record of thoughts, assignments to control night eating by placing reminders around the kitchen, introducing physical activity, and food journaling¹⁷
• Family therapy - sessions with the family help in providing a conducive home environment for recovery and healing
• Meditation - deep breathing sessions along with muscle relaxation treatment improve sleep, increase awareness of hunger and fullness, and reduce stress-related eating

Studies have shown that behavioural treatments, such as progressive muscle relaxation therapy and behavioural weight loss therapy (a low-calorie diet combined with exercise, improving sleep hygiene, and group therapy sessions), reduce night eating habits, decrease anxiety and stress, and improve daytime appetite.¹⁷

Medicinal approach

Studies have shown that a course of either paroxetine or fluvoxamine (selective serotonin reuptake inhibitors; SSRIs) showed significant improvements in all aspects of NES, including food intake, weight, and depression.¹⁸

Phototherapy

Also called light therapy, it involves ultraviolet rays of 10000 Lux for 30 min are given in multiple sessions, to reduce symptoms of depression and anxiety in nonobese people suffering from NES.¹⁸

Stress management 

Following a regular meal plan, making diet adjustments, practising mindful eating, incorporating breakfast into your diet, avoiding caffeine at night, and self-monitoring your progress are all effective ways to reduce stress eating.

Prevention 

It can be hard to admit you have a problem and ask for help. It can be due to feelings of guilt or shame, which are a product of NES and a contributing factor. Hence, it is recommended to use screening questions. NHS recommends talking to an advisor in confidence from an eating disorders charity, at the Beat helpline on 0808 801 0677.

Awareness and screening are prerequisites for treating NES. A GP may send you to specialists to diagnose the syndrome. Treatment is followed by an interprofessional healthcare team that includes psychiatry, internal medicine, and mental health professionals. 

FAQs

How do I know if I have night eating syndrome?

If you wake up multiple times in the night to eat, 3 to 4 times in a week, have hunger pangs after dinner, consume more than 25% of your daily intake after dinner, and skip breakfast in the morning, you may have night eating syndrome.

How is night eating diagnosed?

By physical examination, maintaining a sleep diary, or participating in an overnight sleep study to monitor your symptoms.

Can it be prevented?

Having healthy meals, maintaining sleep hygiene, keeping active, keeping regular checks on your mental health, and exercising are some ways to prevent night eating.

What are the complications of night eating syndrome?

Diabetes, high blood pressure, and heart disease.

Summary 

Anxiety plays a major role in causing night eating syndrome. It has been found that night eating habits can reappear, even after a course of treatment, in the presence of anxiety and stress. Hence, the treatment of NES involves pharmacological and cognitive therapy with lifestyle changes, along with stress management and relaxation techniques.