The Best Foods to Eat When Taking Metformin for Weight Loss
Updated on September 25, 2025
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Metformin is a common medication used to treat type 2 diabetes. Healthcare providers also often prescribe it off-label to support weight loss in people with prediabetes and obesity, among other health concerns, according to Cleveland Clinic Journal of Medicine and Harvard Health Publishing.
While there’s no set diet to follow when you take metformin, prioritizing nutrient-dense, whole foods can promote blood sugar regulation and weight loss. Your doctor or registered dietitian-nutritionist can work with you to create an eating plan that best suits your specific needs.
How Metformin Works
Metformin falls into a class of drugs referred to as biguanides. These medications help decrease the amount of glucose your liver produces and boost your body’s response to insulin, Cleveland Clinic notes. Metformin also decreases the amount of glucose your body absorbs from the food you eat, according to MedlinePlus.
Despite these positive effects on blood glucose regulation, it’s important to pair metformin use with a healthy diet and regular physical activity for best results.
What to Eat When Taking Metformin for Weight Loss
When taking metformin, prioritizing a balance of nutrient-dense, whole foods is essential to supporting weight loss goals, according to StatPearls.
During digestion and metabolism, certain types of foods, namely carbohydrate-containing foods get broken down into glucose, StatPearls notes. Your body uses this glucose to supply your cells with energy. And if you have more glucose than your cells need, your body stores it in your liver or muscles for later use or turns it into fat.
You don’t need to omit carbohydrates from your diet, but it’s important to pay attention to portion sizes and opt for healthy sources of carbohydrates. According to MedlinePlus, healthy carbohydrate-containing foods include:
- Beans, peas, and lentils
- Breads, starches, grains, and cereals
- Fruit
- Milk and yogurt
- Starchy vegetables such as potatoes, peas, and corn
Choosing healthy carbohydrates, while avoiding processed foods with added sugar, sodium, and fat, is a core component of a diabetes-friendly diet, Mayo Clinic notes.
It’s also important to balance these healthier carbohydrate sources with lean proteins, non-starchy vegetables, healthy fats, and plenty of water. This diet helps support weight loss efforts while taking metformin, and it is key to meeting your nutritional needs, according to the American Diabetes Association.
Consult a registered dietitian-nutritionist for help determining the best mealtimes and daily calorie goals for you. They can help you portion foods in a way that promotes healthy and sustainable weight loss while also keeping your blood sugar in range.
Potential Side Effects of Metformin
Like many prescription medications, metformin may cause uncomfortable side effects that make adhering to an eating plan challenging, according to Cleveland Clinic.
These include:
- Bloating
- Diarrhea
- Increased gas
- Metallic taste in the mouth
- Nausea
- Stomach pain
These symptoms tend to be more common in people who are just starting the medication. If you’re experiencing gastrointestinal issues, take your medication with food as directed. If symptoms persist, ask your doctor about a lower dose or an extended-release version of metformin.
People who take metformin for several years may also be at increased risk of vitamin B12 deficiency, according to a study published in October 2025. Though rare, more serious side effects such as lactic acidosis can occur with metformin use as well, StatPearls reports.
The Takeaway
- If you're taking metformin for weight loss, choose a diet rich in whole, nutrient-dense foods to boost results and regulate blood sugar levels.
- Consider working with a healthcare provider or dietitian to create a personalized meal plan that balances healthy carbohydrates with lean proteins, non-starchy vegetables, and nutritious fats.
- Be aware of potential gastrointestinal side effects associated with metformin, like nausea and diarrhea, and discuss prolonged issues with your doctor.
- Although rare, metformin can lead to more serious complications such as lactic acidosis or vitamin B12 deficiency, so it’s important to stay informed and get regular check-ups with your healthcare provider.
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Elise M. Brett, MD
Medical Reviewer
Elise M Brett, MD, is a board-certified adult endocrinologist. She received a bachelor's degree from the University of Michigan and her MD degree from the Icahn School of Medicine ...
Jill Corleone, RD
Author
Jill is a registered dietitian and health writer based in Honolulu. She spent the early part of her career working in a traditional setting as a clinical dietitian in a hospital, t...
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Resources
- Rodriguez P et al. Should I consider metformin therapy for weight loss in patients with obesity but without diabetes? Cleveland Clinic Journal of Medicine. September 2023.
- Shmerling R. Is Metformin a Wonder Drug? Harvard Health Publishing. April 8, 2024.
- Biguanides. Cleveland Clinic. May 22, 2023.
- Metformin. MedlinePlus. February 15, 2024.
- Alyafei A et al. The Role of Dietary Lifestyle Modification in Chronic Disease Prevention and Management. StatPearls. May 19, 2025.
- Holesh JE et al. Physiology, Carbohydrates. StatPearls. May 12, 2023.
- Carbohydrates. MedlinePlus.
- Diabetes diet: Create your healthy-eating plan. Mayo Clinic. June 11, 2024.
- Tips for Eating Well. American Diabetes Association.
- Side Effects of Metformin: Watch Out for These Signs. Cleveland Clinic. March 4, 2025.
- Sepassi A et al. Associations between long-term metformin use, the risk of vitamin B12 deficiency, and neuropathy: An All of Us research Program study. Diabetes Research and Clinical Practice. October 2025.
- Dyatlova N et al. Metformin-Associated Lactic Acidosis (MALA). StatPearls. April 17, 2023.