Is metformin helping or hindering my keto diet?

I have been on metformin ER for almost a year now. While i feel that it is helping with my numbers, I am wondering if it has any impact on the keto (high fat low carb low protein) diet that i have been eating.

It is extremely hard for me to lose weight, even when i follow the guidelines, take less insulin, and exercise.Is there any way that the metformin could be disturbing the process of ketosis?

I never thought to look into this until now...finding some answers but all seem too complicated!

Any advice, answers, or experience!


I think that it would promote ketosis under the right dietary conditions, metformin causes your muscles to metabolize more glucose. if your dietary intake of carbs is low that glucose needs to be created from non carb sources so fat or protein. fat breakdown is the preferred metabolic pathway. the fat breakdown leads to ketone production.

I think that protein breakdown causes you to spill an increased amount of urea in your urine.

This is just off the top of my head, will see if I can find some literature.

they are now calling metformin use in the absence of insulin resistance an ED behavior and comparing it to Diabulimia

If you look at Andrea's profile, she has really good blood sugar control. I don't think it is fair to suggest that wanting to use less insulin is comparable to diabulimia. There are in fact good reasons to not take took much insulin which is known to promote weight gain. Too much insulin (hyperinsulinemia) can have other negative health consequences.

Metformin itself should not have any effect on a ketogenic diet. It may have some effect on your body when you eat a ketogenic diet, but it should all be positive complements to the diet. Metformin improves insulin sensitivity, reduces the production of glucose by your liver and impedes the absorption of carbohydrates during digestion. All this should have a postive effect on weight loss and should improve outcomes from a ketogenic diet.

At a certain point, ketosis itself may not cause you to lose any more weight. You may have reached a natural setpoint, it isn't necessary the only possible setpoint, but your body is comfortable there. To lose weight you may have to break this plateau, which may require you to make other changes. Have you tried intermittent fasting or perhaps some weightlifting?


Thanks for the excellent response, as usual. All of that makes total sense. And i do believe the metformin has done great things! As for the weight loss...I have definitely hit a plateau. I have played with IF a bit but need to be more consistent with it. I am also willing to count calories...I have been reaching out to blogs and forums to see if any other T1s have experienced a plateau like this.

I can say that I definitely DO NOT have diabulimia. I am strict about my control and bolus/correct whenever it is necessary. I would love to take less insulin...for a lot of reasons, but would never deny myself the bolus that is needed.

In the springtime I am able to take long long walks which allows me to be on a temp basal for hours. This is when I feel best.

I do believe that IF is the answer...I just cant seem to get myself to do it properly.

I am open to all suggestions.

I'm not familiar with the new DSM but diabulimia was never a specific disorder. It is misues of medication that was criterion for EDNOS and Bulimia. So it could be using too much tyroxine or using metformin in the absence of insulin resistance. That's considered a form of purging.

I think the attitude might change so that doctors only prescribe metformin if there is clear insulin resistance (x number of units per kilogram to accomplish a certain level of control) or PCOS. Given the fact that ED is so prevalent in type 1.

If it is prescribed by a doctor its not misuse. I just think it is interesting that metformin misuse came up on this story on Good Morning America.

the point in posting the GMA story was not to explain diabulimia it was because they continue on to commentary on the issue of misuse of metformin, or what they characterize as misuse of metformin. they have specialists from Joslin speak on the metformin issue

Doesn't metformin cause your liver to produce less glucose? It seems pretty dangerous to me, and I think there could be some unforeseen consequences of going on a highly restrictive diet, and then complicating things by taking a medication that messes with the body's natural production of glucose, how it processes glucose, and digestion.

Actually, metformin tampers down an overactive liver, and for some T1s it may enable better basal control. Metformin use by T1 has been around a long time. A recent Medscape article discusses the current state of understanding and concludes that T1 patients who are overweight, require large doses of insulin or have uncontrolled A1c are appropriate candidates for metformin. In fact, JDRF has initiated a new study of the benefits of metformin for T1. Andrea has obtained this from her doctor and from everything I've seen her doctors actions are consistent with current understanding and practice.

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My concern is with the Keto diet plus metformin.

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thanks for the reply, Sally. I have been able to greatly reduce my insulin as well! and I feel so much healthier, and controlled on a keto diet. It is only recently that my weight is slowly climbing...despite the fact that i have needed much less insulin this week. I assume it might be water weight? Or time of the month? Or the fact that when I have a streak of beautiful numbers I seem to gain a bit of weight.

Did anyone come to any conclusions as to whether met hinders ketosis ? I have had some recent personal experience and from observation met does attenuate dietary ketosis.

Hi Chelsea!

Can you tell me more about this?! Love to know.


Andrea, don't know if this will be helpful, but thought I should mention it.

It all really does come down to a simple principle from physics, that diabetes hasn't an exemption for: Conservation of energy.

If you burn more calories in a given period (day, week, month) than you consume, you will lose weight. Period.

So, when you are having trouble losing, it's simply because you are eating enough calories -- no matter the source -- to meet your energy needs.

Just like dosing insulin, measurement and precision will improve your results. The most effective and successful way to lose weight is to precisely measure and record total calories eaten each day, and adjust that going forward based on your weight loss results.

My advice would be to count very carefully and then calculate based on weekly numbers. I.e. if you ate 10,000 cal in a week and lost 1 lb, and that was your goal, great! If you gained a pound, dial it down to 9000 and repeat. Find your energy equilibrium while functioning ketogenic, then play with things to find out how many calories while functioning in ketogenesis will result in a loss of a pound in a week.

Once you've obtained all this information, you can predictably control your weight.

I speak from experience on this (not the ketotic diet, but the rigorous methodology to characterize weight dynamics), and it works beautifully.

Hi Andrea,
I have been on the Keto journey for the last 4-5 weeks. Was on 40 units Lantus (nightly long acting) and 2000 mg metformin BD. I was also on Humalog (as per carbs taken). T2 for last 10 years. 41 years old.

I went on a diet in the summer of 2017 and lost about 20 pounds - low carb low fat and tones of excercise. I had frequent low sugars and doc lowered my Lantus, he was not willing to take it out till my fasting went to 80!

I wasn’t able to sustain the loss and so gained everything back as quickly within 3 months.

This time around, I discovered Keto and found a new doc from IMDP. And went from 40 to 35 to 20 to 0 within 3 weeks. Fasting sugars went crazy high for a week every time I lowered my dose. That made my resolution even stronger and I decided to even eat lesser carbs. Now after 4 weeks I am Lantus free and feel great.
This is about 3 days where I have lowered my metformin form 2000 to 1500 and fasting has gone up. But weight is coming down.

I am watching what I eat and have restricted my calories using the app called total Keto diet. Find a new doc of your endocrinologist is old school.

Hopefully not too late for you, seeing that it’s 5 years now :slight_smile: Didn’t know about Keto till Nov of 2018!
Good luck

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If you are taking insulin and metformin, I don’t think it’s the metformin that’s hindering your weight loss. It’s likely the insulin. The keto diet doesn’t depend on low carbs to lose weight. It relies on low insulin. You get to low insulin by restricting carbs. But if you’re taking insulin then you are stopping that process of switching from Mtor to AMP-K.

I am NOT telling you to stop taking insulin. You need to follow your doctor’s recommendations on diet, meds, and life-style.

I’m sure Brian meant, but not said, that less insulin by reducing carbs and perhaps excess protein to maintain the good BG control.

I take metformin while keto. A lot of T2 do. I haven’t seen any reason not to.