Weight Gain

Fight olanzapine (Zyprexa) cravings: A Registered Dietitian advises

February 7, 2024

Written by Chandana (Chandy) Balasubramanian

Medically reviewed by Rita Faycurry, RD

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Key Points

  • Olanzapine (Zyprexa) and other antipsychotics cause weight gain as a side effect.
  • Olanzapine is often prescribed because it's more effective and faster acting than many other antipsychotics, despite its side effects.
  • However, the weight gain from olanzapine can negatively affect your mental and physical health.
  • Managing your weight on antipsychotics can be challenging. A Registered Dietitian can offer valuable support in this journey.

Antipsychotics like olanzapine (Zyprexa) and clozapine (Clozaril) are commonly prescribed antipsychotic medications. 

Olanzapine is often prescribed to treat schizophrenia and bipolar disorder because it's very effective and works faster than some other drugs, quickly helping with severe symptoms like hallucinations and mood changes.

However, a significant side effect is weight gain, which can impact both mental and physical health, sometimes leading people to stop or avoid the medication altogether.

This article explores how olanzapine works, how it causes weight gain, and ways to control olanzapine cravings, with insights from a Registered Dietitian.

How does olanzapine work?

Olanzapine balances brain chemicals, particularly dopamine and serotonin, to reduce schizophrenia symptoms like hallucinations and delusions. With bipolar disorder, it stabilizes mood swings, aiding in both manic and depressive phases.

Why does olanzapine make you gain weight?

Registered Dietitian Rita Faycurry, RD, explains, “Weight gain from antipsychotics like olanzapine is common enough that it has its own acronym—AIWG, which stands for antipsychotic-induced weight gain.

Olanzapine and Clozapine, in particular, can cause intense hunger cravings, affect your metabolism, lead to insulin resistance, and make you store more fat faster.”

Here’s a little more detail on how olanzapine makes you gain weight:

  • Increases hunger and cravings: Many people report intense food cravings on olanzapine and the constant urge to binge eat. This is because the drug affects your hunger-regulating receptors and other chemicals in your brain.
  • Slows metabolism: It also tweaks your metabolism, dialing down your calorie-burning efficiency, which leads to weight gain. So, you’re eating more but burning less energy.
  • Encourages fat storage: Olanzapine also tinkers with how your body handles fats and sugars, nudging it towards storing more fat.
  • Leads to insulin resistance: A study shows that long-term use of olanzapine is linked to insulin resistance, which leads to weight gain and obesity.
  • Sedation effect lowers activity levels: Olanzapine can indirectly cause weight gain through sedation. This happens because it blocks histamine receptors in the brain, which are important for keeping you awake. As a result, you might feel drowsy (similar to the effect of some allergy medications). If you're constantly sleepy and have low energy, you're less likely to be active or exercise, which can lead to weight gain.

What are the health effects of antipsychotics weight gain?

Mental health effects

Weight gain from olanzapine can negatively impact your mental health, potentially leading to decreased self-esteem, body image issues, and increased risk of depression.

Since olanzapine and clozapine ramp up the urge to eat, they may be a worrisome trigger for people with body dysmorphia or eating disorders like bulimia, binge eating disorder, or orthorexia.

Physical health effects

Weight gain from olanzapine can adversely affect physical health by increasing the risk of obesity and diabetes. This is because studies show that antipsychotics also block dopamine receptors in the pancreas, making you gain weight faster and increasing your risk of diabetes.

Additionally, antipsychotics can also raise cholesterol levels and the risk of heart disease. It may also lead to metabolic syndrome, a cluster of conditions that can lead to other health problems.

What’s worse is that people with obesity and metabolic syndrome may also be more likely to relapse or be re-hospitalized due to symptoms of severe mental illness, research shows.

How to control your weight on olanzapine?

According to Rita Faycurry, RD, “There are ways to control your weight on olanzapine and other antipsychotics, but it is essential not to make any changes to your medication regimen without consulting your healthcare provider.”

Your doctor may prescribe metformin to help counteract weight gain from antipsychotics like olanzapine. Another option is Lybalvi, which combines olanzapine with samidorphan to reduce weight gain.

Some other antipsychotics, like aripiprazole (Abilify), cause less weight gain, but only your healthcare provider can help you figure out what meds work best for you.

There's also an ongoing discussion in the medical community about whether OzempicWegovy, or Mounjaro could help with weight loss in olanzapine users. However, these drugs are new, and more research is needed on their effectiveness with antipsychotics.

How to fight olanzapine food cravings?

You may feel immense relief when olanzapine helps alleviate your symptoms of bipolar disorder or schizophrenia, but battling intense food cravings all day can be distressing.

Faycurry RD advises, “When managing food cravings due to antipsychotic-induced weight gain (AIWG), aim for balance instead of perfection. Recognize that weight gain is a common side effect of these medications. Focus on making nutritious foods more accessible while keeping 'fun foods' as occasional treats.”

If you indulge in cravings, don't be too hard on yourself. Remember, weight loss is a complex, personal journey. A Registered Dietitian can provide valuable guidance along the way.

Fay can help you find a Registered Dietitian Nutritionist near you, covered by insurance.

Until you find what works for you, here are some ways to manage food cravings on antipsychotics, antidepressants like Mirtazapine, and other prescription meds.

1. Identify patterns in your hunger cravings

Observe when your cravings occur: do they happen just after eating, late at night, a couple of hours post-meal, or between meals?

Pay attention to times of transition, like your commute or after dinner. Understanding when your food cravings are strongest can help you develop more effective ways to handle them.

Note: If you are worried about triggering an eating disorder or thoughts of disordered eating, consider working with an experienced Registered Dietitian instead of tackling it alone.

2. Delayed gratification may help

If you find yourself constantly craving sugary drinks or fast food, it can be tough to resist, particularly when your meds increase your appetite.

One strategy that may help is slowly extending the time between feeling the craving and indulging in it. This gradual approach can help weaken the hold these cravings have on you.

Some ways to make it easier to resist cravings include:

  • Try to drink a glass of water before eating that bag of chips or drinking that soda.
  • Eat some protein and healthy fats before you indulge your cravings to help control insulin spikes. Some easy, no-fuss protein sources are nuts like pistachios (unsalted), sliced deli meat, boiled eggs (peeled and in your fridge; they can stay there for seven days), and Greek yogurt.
  • Keep low-calorie, easy-to-grab, fiber-rich snacks on hand. For example, consider storing carrot and celery sticks in your refrigerator to eat when cravings begin.
  • Practice urge surfing by acknowledging your cravings and riding the wave. Cravings can last about 20 minutes, so waiting it out lowers the intensity of your craving.

What if you're in situations like a Superbowl party, a child's birthday, or out with friends, where it’s tough to manage your environment? Do your best to manage what's within your control. Eating before you go to the event may help lower the intensity of cravings.

3. Try to lower your dependence on added sugars

Added sugars are sweeteners put into processed foods and drinks. They are linked to obesity, type 2 diabetes, cardiovascular issues, and even dementia.

Before your usual sugar cravings start, try eating natural sugars. If you still want something sweet later, you've already given your body some natural fiber and nutrients from the fruit.

For example, if you want a bag of Oreos, would your brain be okay if you ate a few strawberries dipped in chocolate first and waited 10, 15, or 20 minutes to see how you felt? Another option is having an apple or pear right after lunch if you crave sugar.

4. Balance your plate but make room for treats

Try to balance your plate with predominantly whole vegetables, whole fruit, whole grains, lean meats, and healthy fats. You could add a green salad before lunch and dinner.

Consider starting your day with a savory breakfast containing proteins and fats, like savory oatmeal with pumpkin seeds, stir-fried veggies with eggs, or an omelet with veggies (you could chop and meal prep veggies beforehand).

If you’re vegan, a quick tempeh or tofu stir-fry with greens like spinach, bok choy, or broccolini on sourdough bread or a little rice could give you a nutritious and tasty meal.

5. Get personalized support from a Registered Dietitian

If you’re fighting olanzapine cravings, it can be extremely disheartening to do it alone. Working with a psychiatrist and a Registered Dietitian for support could help you achieve your goals.

A Registered Dietitian will work with you to create a personalized nutrition plan and can help you manage your weight on prescription medications.

Use Fay to find a Registered Dietitian near you, covered by your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.


Fay Nutrition has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

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Chandana (Chandy) Balasubramanian

Written by Chandana (Chandy) Balasubramanian

Chandana Balasubramanian is an experienced healthcare executive who writes on the intersection of healthcare and technology. She is the President of Global Insight Advisory Network and has a Master’s degree in Biomedical Engineering from the University of Wisconsin-Madison, USA.

Rita Faycurry, RD

Medically Reviewed by Rita Faycurry, RD

Rita Faycurry, RD is a board-certified Registered Dietitian Nutritionist specializing in clinical nutrition for chronic conditions. Her approach to health is centered around the idea that the mind and body are intimately connected and that true healing requires an evidence-based and integrative approach that addresses the root cause of disease. In her books and articles, Rita offers practical tips and insights on how to care for your body, mind, and spirit to achieve optimal health and wellness.