Depression can cause weight changes, which may be due to physical changes in the body as a result of depression itself, side effects of antidepressants, or changes in appetite and relationship to food.

There is a close link between depression and weight changes, which can work both ways. Drastic changes in weight may affect a person’s emotional state and create physical changes in their body that can also affect their mood.

Depression can change a person’s eating habits, level of physical activity, and metabolic system, which can all affect weight.

This article looks at the link between depression and weight and steps a person can take to manage depression and weight changes that may occur.

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Changes in appetite, diet, and eating patterns are common in depression.

Depression can cause a loss of appetite, which may lead to weight loss. However, depression may instead cause an increase in appetite and therefore weight gain. Researchers now describe two types of depression:

Weight loss may occur if people lose interest or pleasure in eating, which may happen as a result of changes in the brain’s reward system that occur with depression.

Antidepressants can also cause weight loss or weight gain. And other possible side effects of antidepressants, such as nausea and insomnia, may affect eating habits and weight.

Research has shown that rates of depression are twice as high in people with obesity than in those without. Researchers are still unsure whether obesity leads to depression or whether depression leads to obesity.

Depression and obesity may occur as a result of a change in stress responses in the body. Other factors that may link the two conditions include:

Read more about the link between obesity and depression.

Obesity can cause risk factors for depression, such as:

  • reduced physical activity
  • changes in thought patterns, such as rumination
  • changes in appetite
  • changes to the hormone and cytokine systems

Diet can affect both weight and mental health. A diet that is high in fat and sugar or includes more than the recommended number of calories can increase the risk of obesity.

People following a healthy diet have a lower risk of experiencing or developing symptoms of depression.

Weight changes can be a side effect of antidepressants, although medications may affect each person differently.

According to a 2018 study, antidepressants increase the risk of weight gain, which can vary depending on the type of antidepressant. The researchers found that the risk of weight gain was greatest during people’s second and third years of taking antidepressants.

The risk of 5% or more weight gain was 46.3% greater in people who were in their second year of antidepressant treatment than in the general population. These findings applied to people from a wide range of demographics.

According to a 2020 study, weight changes are a possible side effect of many antidepressants. Tricyclic antidepressants may lead to many side effects, including obesity. Monoamine oxidase inhibitors may also cause weight gain.

Certain antidepressants may lead to weight loss in some people. For example, a common side effect of venlafaxine is nausea, which could make people feel like eating less.

One of the significant side effects of long-term treatment with selective serotonin reuptake inhibitors in study participants was weight loss.

Learn more about antidepressants and weight gain.

Anhedonia — the loss of pleasure or interest in things a person may usually enjoy — is a key symptom of depression. Anhedonia may affect a person’s eating patterns.

Anhedonia and certain emotional states, such as depression, may have a link to certain behaviors that make it more difficult to lose weight, such as stopping a weight loss program or reducing cardiovascular exercise.

In people with obesity, high levels of anhedonia may also contribute to lower fitness levels and an increased risk of stopping a weight loss program.

Depression can affect sleep patterns, and people experiencing it may have difficulty sleeping. Insomnia can also be a side effect of some antidepressants.

Insufficient or poor quality sleep increases the risk of overweight and obesity, metabolic changes, dysfunctional eating patterns, and reduced physical activity.

A 2019 study found that emotional eating — eating as a response to negative emotions — is linked to depression and the development of obesity.

The researchers concluded that people with higher rates of emotional eating who slept for shorter durations at night may have a higher risk of weight gain.

Research suggests that increasing physical activity and sleep duration may help people reduce excessive intake of foods high in fat and sugar as a response to negative emotions. This may help them regulate their weight.

If people find that they lack motivation to exercise, they may start with short durations of low impact exercise such as walking. People can consult a healthcare professional for advice and to discuss an exercise program that may help.

If depression is affecting a person’s sleep or a person thinks antidepressants may be causing insomnia, a doctor may be able to suggest treatments or a change in medication.

People may also need to alter their diet by reducing or increasing calories, depending on whether they want to gain or lose weight. People may find it helpful to speak with a doctor or dietitian who can help them create a tailored eating plan.

If people need urgent help or need to talk with someone, they can call a helpline such as the SAMHSA helpline or call 988 to reach the Suicide & Crisis Lifeline, which is available 24/7.

Learn about foods that may help with depression.

Treatment and lifestyle changes may help people manage depression and weight changes.

Losing weight may help improve symptoms in people who have depression and obesity.

If people with depression are concerned that they are losing weight, speaking with a health professional about increasing their calorie intake, as well as checking for underlying causes, may help.

A doctor can help people work out a treatment plan to target depression and any associated weight changes. A doctor can also help people find a mental health professional if necessary.

Depression can cause weight loss or weight gain. This may be due to changes within certain body systems, a side effect of medications, or mood changes that affect eating patterns and appetite.

If people with depression find it difficult to regulate their weight, they can talk with a healthcare professional about treatment options.

Treatment may include a change in medication type or dosage, an exercise program, and a dietary plan.