Fasting is increasingly popular to help treat certain health conditions. Some researchers say fasting may help with depression, while others believe it could worsen your mood.

People fast for many reasons, from helping with digestion and weight control to religious and cultural practices. Since the time of Hippocrates in ancient medicine people have also used fasting to help treat various health conditions.

In recent years, researchers have become increasingly interested in the ways different types of fasting might affect the body and mind. This includes how fasting affects mental health conditions, including depression and other mood disorders.

Fasting is associated with some negative effects — such as negative moods and the potential for nutrient deficiencies — but many who fast report an improvement in psychological symptoms. We look at what the research says.

Fasting is when you restrict your intake of solid and liquid foods. You can do this in several ways. Some common types of fasting include:

  • intermittent fasting: not eating for a certain period, such as fasting for 12 to 18 hours a day or fasting for 24 hours once or twice each week
  • alternate-day fasting: eating every other day, and consuming no or few calories on the days in between
  • modified alternate-day fasting: eating 25% of your usual intake every other day

Some researchers believe that fasting can help reduce certain mental health issues, including depression.

For example, a 2021 review reported that people who fasted had lower anxiety and depression scores than control groups who did not fast. These data came from 5 randomized controlled trials.

On the other hand, a 2022 review concluded that fasting may lead to negative emotions like irritability, but also positive experiences, like a sense of accomplishment and control. The researchers say there isn’t enough evidence to determine whether fasting is beneficial overall.

In theory, fasting may alleviate depression symptoms in a variety of ways, including the following:

Weight control

Researchers have identified a link between obesity and depression. For some people, fasting can help with depressive symptoms by facilitating weight loss.

Importantly, fasting can be complicated for people with a history of disordered eating. If you’re thinking of trying fasting it’s important to talk with a medical doctor or mental health professional about the safety and risks.

Metabolism changes

Daily intermittent fasting may cause your body to switch from breaking down glucose to breaking down ketones. This helps stimulate anti-inflammatory and antioxidative effects that help the body resist stress.

According to 2022 research, fasting may change your metabolism in the following ways:

  • improved cholesterol and lipid (fat) levels in the blood
  • increased ketones in the blood
  • reduced levels of glucose in the blood

Some research suggests that fasting may also improve gut microbiota by reducing gut inflammation and reducing the amount of blood dedicated to digestion.

Calorie restriction

Intermittent fasting is often combined with calorie restriction, another fasting intervention.

A 2021 review found that both calorie restriction and intermittent fasting may be useful in treating depression due to possible changes in fatty acid levels and neurotransmitters, along with other metabolic effects.

A review from 2022 reports mixed results about how fasting affects psychological health, with both positive and negative effects. Some studies showed no significant differences in emotions when fasting or not fasting.

Negative effects

Some studies in the review suggested that fasting can increase negative experiences, such as:

The reason for this is unclear. It may be because food restriction affects your energy intake or the availability of energy from glucose (a form of sugar you get from the foods you eat). Low blood and brain glucose levels are associated with poor mood and may affect how well you can think or concentrate.

Positive effects

Other studies suggest fasting can increase positive moods and vitality, and decrease negative moods. In a 2016 study of fasting among healthy women, fasting helped increase positive feelings, including a sense of:

  • achievement
  • reward
  • pride
  • control

In a 2020 study of fasting among Muslim students during Ramadan, fasting helped promote:

  • overall psychological well-being
  • self-acceptance
  • autonomy
  • positive relations
  • environmental mastery
  • personal growth

Some believe these positive experiences may be connected to strong religious beliefs (when fasting for religious reasons), which can positively affect physical and psychological health.

Fasting is also closely related to emotional self-control, such as controlling the desire to eat. Completing a fast may increase your feeling of self-control.

If you’re considering fasting, be sure to discuss it with a healthcare professional first. Certain types of fasting may positively affect your health, helping with things like blood sugar control, blood pressure, and inflammation. But for some, fasting may cause problems.

Reduced energy

Fasting can cause low energy or more fatigue, which is a common symptom of depression.


When your body is deprived of food your brain’s hunger center and appetite hormones go into overdrive. This can cause some people to overeat after a fasting period.

Losing too much weight

For some, fasting can lead to significant weight loss, affecting your bones, energy level, and overall immune system. This may be harmful to certain populations, such as older adults or people with a history of eating disorders.

Nutrition deficiencies

When fasting it’s especially important to eat a range of nutritious foods to avoid nutritional deficiencies. According to the Centers for Disease Control and Protection (CDC), a nutritious diet includes:

  • fruits
  • vegetables
  • whole grains
  • low fat milk and milk products
  • protein sources, such as seafood, lean meats, eggs, legumes, nuts, and seeds

Side effects with certain conditions

If you take medications for blood pressure or heart disease while fasting you may be more prone to imbalances of sodium, potassium, and other minerals that affect your body’s functions.

Fasting can also be dangerous for people with certain conditions, such as diabetes (due to the chance of hypoglycemia, or low blood sugar).

Unwanted physical and mental symptoms

Depending on the length of your fast, you may experience side effects, such as:

  • headaches
  • dehydration
  • fainting
  • low blood sugar
  • constipation
  • lethargy
  • feeling irritable or cranky

To help reduce unwanted side effects, you might try out a different type of fasting or speak with a dietician or mental health professional for guidance.

Research shows that while fasting can lead to negative emotional states, such as anger or irritability, it can also result in positive states, like a sense of reward or accomplishment. The research is mixed as to whether fasting can improve symptoms of depression.

Fasting may help your body regulate symptoms of depression by contributing to weight loss, changing your metabolism, or promoting calorie restriction.

If you’re considering fasting you may benefit from talking with a healthcare professional. Fasting can cause problems for some people, and a specific fasting schedule may work better for you than others to avoid unwanted side effects.

For help with depression, many people start by talking with a general physician. They can refer you to a mental health specialist, who can offer emotional support and provide depression resources. Psych Central’s How to Find Mental Health Support resource can help you find a therapist who’s right for you.