Many medications can affect our weight, whether it’s weight gain or unintended weight loss. At Pharma Care, we understand how weight changes can affect your quality of life and self-confidence. In this article, we’ll explain the connection between medications and weight, which common medications can cause weight changes, and how to deal with these effects safely and effectively.
How do medications affect weight?
The effect of drugs on body weight can occur through several different mechanisms:
- Change in appetite – increased or decreased feeling of hunger
- Effect on metabolism – slowing down or speeding up
- Change in the way fat is stored in the body
- Fluid accumulation (edema)
- Effect on hormonal activity
- Mood changes that lead to emotional eating
It is important to understand that not every person will experience the same side effects, and the severity of the effect on weight varies from person to person depending on genetic factors, dietary habits, level of physical activity, and more.
Common medications that cause weight gain
Weight gain from medications is a common side effect of several drug groups. Here are the main groups:
| Drug group | Examples | Mechanism of influence on weight |
|---|---|---|
| Psychiatric medications | Olanzapine (Zyprexa), quetiapine (Seroquel), lithium | Increased appetite, slowing metabolism, affecting the satiety center in the brain |
| Antidepressants | Amitriptyline, mirtazapine (Remeron), Prozac | Increased appetite, effect on serotonin levels |
| Diabetes medications | Insulin, glyburide, glipizide | Increasing glucose storage in cells, increasing appetite |
| Epilepsy medications | Valproate (Deflavent), carbamazepine (Tegretol), gabapentin (Neurontin) | Increased appetite, slowed metabolism |
| Steroids | Prednisone, dexamethasone | Increased appetite, change in body fat distribution, fluid retention |
| Beta blockers | Propranolol (Dralin), metoprolol | Slowing of metabolic rate, fatigue leading to decreased physical activity |
Common medications that cause weight loss
Weight loss from medication can be a desirable side effect in some cases, but in other cases it can be problematic, especially if it is too rapid or uncontrolled:
- Medications to treat attention deficit hyperactivity disorder (ADHD) – Methylphenidate (Ritalin, Concerta), amphetamines (Adderall) – appetite suppressants
- Medications to treat obesity – Orlistat (Xanediol), phentermine-topiramate (Qissimia) – reduce fat absorption or suppress appetite
- GLP-1 diabetes medications – Liraglutide (Saxenda, Victoza), Semaglutide (Ozampic) – slows gastric emptying and increases feelings of fullness
- Thyroid medications – Levothyroxine (Eltroxin) – increases the metabolic rate
- Chemotherapy drugs – Cause nausea, vomiting, and loss of appetite
- Certain antibiotics – May cause digestive disorders and decreased food intake
How to deal with weight gain from medication?
If you are experiencing weight gain as a result of taking medication, here are some steps you can take:
- Do not stop the medication without consultation. – Never stop medication on your own, even if you experience weight gain.
- Record your weight changes. – Keep a regular diary of weight changes since starting medication.
- Talk to your doctor. – Report weight gain and consider adjusting the dosage or replacing the medication.
- Adjust your diet – Consult with a clinical dietitian to adjust a menu that will balance the effect of the medication.
- Increase physical activity – Regular exercise can help maintain weight even while taking medication
Recommended dietary adjustments during weight gain from medication
- Increase your intake of foods rich in dietary fiber (vegetables, fruits, legumes)
- Make sure to drink plenty of water.
- Reduce your intake of simple carbohydrates and processed sugars.
- Choose lean proteins (skinless chicken, fish, legumes)
- Eat small, regular meals throughout the day.
- Incorporate natural appetite suppressant foods like green tea and cinnamon
Important to know: In cases of significant weight gain (over 51% of body weight) in a short time, you should consult a doctor as soon as possible, as it may be necessary to adjust your medication.
How to deal with weight loss from medication?
Weight loss from medication can be worrisome, especially if it's rapid or if you're already underweight. Here are some tips for coping:
- Nutritional enrichment – Add foods rich in calories and proteins to your daily diet
- Small, frequent meals – Eat 5-6 small meals instead of 3 large meals
- Dietary supplements – Consult your doctor about nutritional supplements that may help.
- Treatment of side effects – If the weight loss is due to nausea or vomiting, ask your doctor for medication to relieve it.
- Strength training – Strength training can help build muscle mass.
Recommended foods in case of weight loss from medication
- Avocados, nuts and seeds – healthy sources of fats and calories
- Olive oil, coconut oil – to enrich dishes
- Raw tahini, natural peanut butter
- Whole milk products (if there is no sensitivity)
- Eggs, fish, meat – good sources of protein
- Dried fruits and honey – to enrich snacks
When to see a doctor about weight changes from medication?
The effect of medications on body weight is a phenomenon that requires medical monitoring. You should consult a doctor in the following cases:
- An increase or decrease of more than 51% of body weight within a month
- Weight changes accompanied by other symptoms such as extreme fatigue, dizziness, rapid heartbeat
- Increased thirst or frequent urination along with weight changes
- Sudden swelling in the ankles, feet, or hands
- Weight changes that affect quality of life or mental state
Alternative treatment options
In some cases, when the effect of medications on weight is significant, the doctor may consider:
- Medication replacement – To an alternative drug from the same group with less impact on weight
- Dose adjustment – Sometimes reducing the dose can reduce side effects
- Drug combination – Adding a medication that can balance the effect on weight
- Timing of taking the medicine – Changing the timing of taking the drug can affect side effects
Important tip: When you start a new medication, ask your doctor for detailed information about possible effects on weight and prepare accordingly in advance.
Frequently Asked Questions
Will everyone who takes medication experience weight changes?
No, not everyone will experience weight changes as a result of taking medication. The response to medication is individual and is influenced by genetic factors, lifestyle habits, age, gender, and more. Some people will take medications known to cause weight gain and experience no change, while others may experience significant weight gain.
How long does it take for medications to affect weight?
The rate at which medications affect body weight varies depending on the type of medication and individual characteristics. In some cases, the effect of medications on weight may begin within the first few weeks of treatment, while in other cases the change is gradual and occurs over months. Psychiatric medications and steroids tend to affect weight more quickly than other medications.
Can weight gain from medications be prevented through diet alone?
A balanced diet and exercise can help reduce weight gain from medications, but it is not always possible to completely prevent it with these measures alone. This is because some medications affect weight through hormonal and metabolic mechanisms that are not directly related to calorie intake. However, maintaining a healthy lifestyle is essential to reduce the negative impact.
Is weight loss from medication always a positive sign?
Not necessarily. While weight loss may be desirable for people who are overweight, rapid or uncontrolled weight loss may indicate a negative side effect of the medication. Unintentional weight loss can lead to muscle loss, weakness, decreased immune function, and other health problems.
Is the effect of medications on weight reversible after stopping treatment?
In most cases, the effect of medications on body weight is reversible, and weight gradually returns to its previous level after treatment is discontinued. However, the process may take a long time, and in some cases, especially after prolonged treatment, weight changes may be more long-term. It is important to work with your doctor on a well-organized plan for discontinuing treatment and monitoring your weight.
Medical Disclaimer: The information in this article is for general information purposes only and is not a substitute for professional medical advice. Do not change, discontinue, or start a new medication without consulting a qualified physician. If you experience significant weight changes or other side effects from taking medication, contact your physician as soon as possible. Pharma Care is not responsible for medical decisions made based on the information in this article.
Prof. Alon Green is an expert in clinical psychiatry and drug research, specializing in the development and adaptation of prescription drugs for a variety of neuropsychiatric conditions. He has over 35 years of experience in clinical and academic work, and has served as a lecturer and visiting professor at several leading universities in Israel and abroad. He has headed research and treatment units in public hospitals and advanced medical centers. His areas of expertise include attention deficit hyperactivity disorder (ADHD), anxiety and sedation disorders, clinical depression and mood disorders, as well as drug therapies that support diet and metabolic balance. He combines evidence-based approaches with pharmacological innovation, and has published dozens of professional articles in scientific journals, making a significant contribution to the understanding of the mechanisms of action of drugs and their clinical effects.
