
Opioid painkillers are closely associated with weight gain. In one study, taking medications including opioids doubled the risk of obesity.[1]
You could gain weight while taking opioids due to many factors, including sedation and changes in your food preferences. When you’re in recovery, you might gain weight for different reasons.
Being overweight or obese can lead to health issues. Your doctor can help you create a healthy eating plan to keep your weight at proper levels. But you must address an underlying opioid use disorder (OUD) first.
Researchers know that opioids can cause weight gain. They've also uncovered the reasons that might connect OUD with weight. These are the issues researchers have identified:
Some people develop OUD after taking medications for long periods to address chronic pain. Sometimes, people develop pain issues due to obesity, and vice versa.
Painful conditions associated with obesity include the following:[2]
Opioids aren't very effective in treating long-term pain, but you may keep taking them due to an OUD. Because your pain is poorly controlled, you don't engage in an active lifestyle and become yet more obese.[3]
Opioids are sedative drugs, slowing down your central nervous system and thought processes. While you're using these drugs, you may feel sleepy and sedated. Feelings like this can keep you from starting or maintaining an exercise routine. A lack of movement can lead to weight gain or obesity.[4]
Opioids work directly on brain cells, and sometimes, changes can cause an adjustment in the foods you prefer to eat. Researchers say long-term opioid use disorder is associated with an increased preference for sweet treats and snacks.[5]
As you replace salads with sweets, your weight will rise. You may replace lean tissues (like muscle) with fat deposits, and you may see the changes when you step on the scale.
Medication for Addiction Treatment (MAT) programs require using prescription medications like methadone or buprenorphine. These therapies help to correct chemical imbalances deep within your brain cells. When you can think clearly, you can focus effectively during your therapy sessions.
The link between MAT options and weight gain is unclear.
In one study, researchers found a link between weight gain and methadone use, but they didn't see the same association in people taking buprenorphine.[6] In another study, researchers did find a link in people using buprenorphine for recovery.[7]
Your medical team can monitor your weight as you participate in MAT programs. If you start to gain weight, they may ask you to change your diet and increase your exercise frequency and intensity.
Not all weight gain that people experience during MAT programs is unhealthy. Many people with an active OUD are malnourished and underweight, and getting into treatment helps them increase back to a healthy weight.
Some people gain weight when trying to get sober, even if they don't enroll in MAT programs.
Some people struggle with cravings for drugs, and they need social opportunities that don't involve substance misuse. Food can fill both gaps. People might eat instead of relapsing, and they might head out to eat instead of meeting friends to use drugs.
Food substitutions like this are healthier than using drugs, but they can lead to their own problems.
Enrolling in MAT programs can help you to find healthy habits to support sobriety. You could learn how to deal with cravings without finding a substitute.[8]
Experts say obesity is associated with an early death.[9] Many serious health problems can take hold when you put on weight.
Those health problems include the following:
If you gain too much weight, your health is at risk. Your doctor can help you determine what to do next.
Your opioid use disorder is life-threatening, and it's critical to both get sober and maintain that sobriety. Your doctor can help you find a way to lose weight safely when your sobriety is secured. Talk to your doctor about how to enroll in an MAT program, or reach out to us here at Bicycle Health to get started.

Peter Manza, PhD received his BA in Psychology and Biology from the University of Rochester and his PhD in Integrative Neuroscience at Stony Brook University. He is currently working as a research scientist in Washington, DC. His research focuses on the role of the brain dopamine system in substance use disorders and in aging. He also studies brain function in obesity and eating disorders.
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