Top 3 Foods to Avoid While Taking Metformin

Authored by The Rx Advocates, / Medically Reviewed by Dr. Conor Sheehy, PharmD, BCPS


All drugs can potentially interact with other substances like foods and supplements. It is essential to know which substances may interact with your medications.

Metformin is a popular prescription medicine used to treat type 2 diabetes. It is prescribed under several brand names including Axpinet, Diagemet, Glucient, Glucophage, and Metabet.

If you’re currently taking metformin, or plan to start taking it soon, it’s important to know which foods you should avoid.

What is Metformin?

Metformin is a medicine used to treat type 2 diabetes in patients over the age of 10. The drug works by helping to lower blood sugar levels.

Metformin is not used to treat patients with type 1 diabetes.

Sometimes, metformin is prescribed to treat other conditions, including polycystic ovarian syndrome (PCOS) and weight gain from antipsychotic medications.

The drug is currently being studied for its potential benefits in limiting the risk of cancer, stroke, and dementia, and slowing the aging process.

The drug is only available by prescription and must be taken orally by tablet or suspension.

It is recommended to monitor blood sugar levels while taking metformin. Changes in diet or exercise levels will affect blood sugar levels.

Overall, the drug has a favorable safety profile, with the most common side effects being mild.

Foods to Avoid While Taking Metformin

Whenever starting a new medication, it is advised to speak with a doctor or pharmacist about potential food and drug interactions. This information can also usually be found in the drug packaging insert.

Here are the top three foods to avoid while taking metformin:


Consuming alcohol while taking metformin can lead to dangerously low blood sugar levels. This is known as hypoglycemia.

Extended states of hypoglycemia can lead to serious side effects such as drowsiness, dizziness, and even lack of consciousness.

Alcohol can also increase the likelihood of developing lactic acidosis. Drinking alcohol can lead to a buildup of lactic acid.

This build-up, if not treated right away, can be fatal. Symptoms of lactic acidosis include trouble breathing, a fast heart rate, and feeling cold.


Grapefruit is notorious for interacting with many prescription medications. Some studies have shown that consuming grapefruit or grapefruit juice while taking metformin can increase lactic acid levels.

This may increase the likelihood of developing metformin-induced lactic acidosis. Take caution when consuming grapefruit.

Simple Carbohydrates

People who have diabetes should try to avoid simple carbohydrates. These can lead to spikes in blood sugar and leave the person feeling unwell afterward.

Examples of foods that are simple carbohydrates include pasta, white rice, and white bread.

It is recommended to avoid these foods entirely or eat them very rarely.

Healthy Substitutes

While there is no healthy substitute for alcohol, there are a few tips to consume alcohol while taking metformin more responsibly.

Try to consume only one drink daily, not on an empty stomach. It is recommended to monitor your blood sugar before, during, and after drinking alcohol.

Grapefruit has unique chemical properties that make it interact with certain drugs. Replacing grapefruit with another citrus fruit may satisfy the same flavor while avoiding possible drug interactions.

Other citrus fruits to try in place of grapefruit might be oranges or kumquats.

Simple carbohydrates should be swapped for more complex carbohydrates whenever possible. As the name implies, complex carbohydrates take longer for the body to digest.

As a result, they cause a more gradual increase in blood sugar than simple carbohydrates.

Some substitutes may include beans, brown rice, and whole-grain bread.

Reducing Metformin Side Effects

As with all advice relating to diabetes management, moderation is essential. Eating well and exercising can help you manage your blood sugar more effectively.

Eating the foods listed above on only an occasional basis will keep you feeling your best.

Another way to reduce side effects includes taking your medication consistently at the same time of day, with the correct dosing as prescribed.

Even when following all recommendations, it is possible to experience side effects while taking metformin. These side effects may have nothing to do with your diet and may result from the medication alone.

Common side effects of metformin include:

  • Stomach discomfort
  • Diarrhea
  • Lower back or side pain
  • Muscle cramping

Less common side effects include:

  • Anxiety
  • Increased hunger
  • Nightmares
  • Slurred speech

Rare side effects include:

  • Behavior changes
  • Difficulty sleeping
  • Loss of strength
  • Drowsiness

If you are experiencing any side effects, you must report them to your healthcare provider immediately. Some side effects may require immediate medical attention, whereas others may go away with continued medication use.

Key Takeaways

Diet can have a big influence on blood sugar. People with diabetes should avoid foods that may lead to hard-to-control blood sugar levels while taking metformin.

Alcohol is the most important food to avoid while taking metformin, since it can lead to severe and possibly fatal side effects. Patients taking metformin should consume alcohol in moderation and with caution.

Grapefruit and grapefruit juice has been shown to have the potential to increase the likelihood of developing lactic acidosis in laboratory studies. It is recommended to avoid grapefruit if you are taking metformin.

Simple carbohydrates lead to sharp changes in blood sugar. People with diabetes should swap simple carbohydrates for more complex ones, whether they are taking metformin to stabilize blood sugars.

As with all decisions relating to health, it is best to discuss your unique situation with your healthcare provider. Metformin interacts with other drug classes, and your healthcare provider will advise you of any additional foods you may need to avoid.

Even when taking metformin as prescribed and avoiding the foods listed, it may be possible to experience side effects. It is best to report all side effects to your doctor immediately, as sometimes they can be life-threatening.

The Rx Advocates and Your Metformin Prescription

The Rx Advocates help people save on their metformin prescriptions. We help our clients receive discounts and assistance they are eligible for to get their prescription for a predictable, low monthly cost.

We work with you and your doctors to prepare and submit the necessary applications on your behalf. Once approved, we manage your prescription, including refills, to ensure you’re never without your medication.

If you want to save on your metformin prescription, contact us today to see if you qualify. Our advocates can help you pay less for your name-brand prescriptions.

  1. National Health Service. Metformin. Accessed November 2022. Available at
  2. Harvard Health Publishing. Is Metformin a Wonder Drug? September 2021. Available at
  3. Healthline. Is it Safe to Mix Metformin and Alcohol? December 2018. Available at
  4. Methods Find Exp Clin Pharmacol. Grapefruit juice improves glycemic control but exacerbates metformin-induced lactic acidosis in non-diabetic rats. November 2009. Available at
  5. Dealing with Diabetes. Foods to Avoid While Taking Metformin. Accessed November 2022. Available at
  6. Harvard School of Public Health. Carbohydrates and Blood Sugar. Accessed November 2022. Available at
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