Although obesity and depression often come hand in hand, exactly how they’re linked has been difficult to determine. A recent study from the University of South Australia and the University of Exeter in the UK sheds new light on the matter, showing that obesity can cause depression even in the absence of other contributing factors.

The Relationship Between Obesity And Depression

Researchers have long been aware of the relationship between depression and obesity–but does one necessarily cause the other? It’s sort of a chicken-or-the-egg situation.

Dr. Jess Tyrrell, lead author of the study, said, “Obesity and depression are both global health problems that have a major impact on lives and are costly to health services. We’ve long known there’s a link between the two, yet it’s unclear whether obesity causes depression or vice versa, and also whether it’s being overweight in itself or the associated health problems that can cause depression.”

According to the Centers for Disease Control and Prevention, about 43% of adults with depression are obese. And they say that those who have been diagnosed with depression are more likely to be obese than those who haven’t. Likewise, children who are depressed are more likely to be overweight.

Still, observational studies have not been able to determine whether obesity causes depression, or depression causes obesity, as there are many competing factors to consider.

For example, people with depression often experience weight gain due to the medications that are used to treat them. In addition, the condition is often associated with overeating and a more sedentary lifestyle, both of which can lead to being overweight.

Is There A Genetic Link?

To better understand the relationship between the two, researchers in the aforementioned study used genetic and medical data from 48,000 people with depression and compared it with over 290,000 controls. Using the available information, they looked at 73 genetic variants linked to high BMI and other related conditions. For these genetic traits, depression risk increased and could be explained by biological mechanisms.

In their analysis, they accounted for a range of factors that could influence the outcome, including socioeconomic position, alcohol consumption, smoking, and physical activity.

The result? They were able to separate the psychological aspects of obesity from the physiological ones.

Professor Elina Hyponnen, who co-led the study, stated, “We separated the psychological component of obesity from the impact of obesity-related health problems using genes associated with higher body mass index (BMI), but with lower risk of diseases like diabetes.”

“These genes were just as strongly associated with depression as those genes associated with higher BMI and diabetes. This suggests that being overweight causes depression both with and without related health issues–particularly in women”

While the work is groundbreaking, further investigation is still needed. Researchers noted that the data was only pulled from people born between 1938 and 1971, so it’s unclear whether the same results would be achieved with a younger generation. In addition, many of the cases of depression were “self-reported”.

Self Care

Depression and obesity are both conditions that require long-term care and attention. However, due to the fact that depression can lead to further overeating and weight gain, some experts say that you should deal with your mental health first.

Signs you may be depressed and need to speak to a professional include:

  • Lack of energy and loss of interest in past activities
  • Reluctance to socialize
  • Becoming sad, lonely, angry, or withdrawn
  • Reluctance to go to work or carry out other obligations
  • Obsession with food and frequent snacking
  • Sleeping too much or too little

Remember: it’s important to be open and honest with your doctor about how you’re feeling and what you’re doing, regardless of whether or not you’re sticking to your care plan. It’s the only way they can monitor your condition and help you continue to improve your health.