The Most Common Cause of Weight Gain

insulin resistance

There can be a strong hormonal component to abdominal weight gain. And in most people, that hormone is insulin.

In episode six of my podcast/YouTube video, I discuss insulin resistance including why you could have insulin resistance even if your blood sugar is normal, the role of mitochondria, and all the ways to lower insulin and improve metabolism.

Also available wherever you get your podcasts.


There can be a strong hormonal component to abdominal weight gain. And in most people, that hormone is insulin. Specifically, I’m talking about insulin resistance. And if you think that sounds complicated and like maybe it doesn’t apply to you, I encourage you to keep listening. Because insulin resistance is, in fact, very common. And could be affecting you even if your doctor said your blood sugar is normal.

Welcome back to the podcast. I’m your host Lara Briden, a naturopathic doctor and author of the books Period Repair Manual and Hormone Repair Manual.

I’ve been a little slow getting this episode out to you because my life got busy. I got c—-d a few weeks ago and then I had to prepare and deliver a big online workshop for practitioners called metabolic health and vitality for women over 40. And if you’re a practitioner and want to check out that recording, you can find the link in the show notes. Fortunately, I’m feeling better now and am back on track with the podcast.

So today, we’re going to talk about insulin resistance which is also called hyperinsulinemia, pre-diabetes, or metabolic syndrome. And it’s common, affecting at least one in two people over 40. And lots of younger people. From a women’s health perspective, insulin resistance can play a major role in PCOS, of course, as well as the weight gain of perimenopause. Insulin resistance can make periods heavier and increase the long-term risk of heart disease, dementia, osteoporosis, and breast cancer.

So, it’s an important topic.

And let’s start with what is insulin resistance? In simplest terms, insulin resistance is dysfunction of the metabolic nuts and bolts of the cell that are supposed to turn food into energy. The result of that metabolic dysfunction is less energy, more inflammation, and a greater tendency to gain fat, especially around the middle. Insulin resistance can also cause high cholesterol, high triglycerides and importantly, something called fatty liver, which is fat accumulation in the liver. Actually, fatty liver is both caused by insulin resistance and a cause of insulin resistance.

So, if you’ve been told you have fatty liver, chances are high you do have insulin resistance, even if your doctor never mentioned it. Why would your doctor not mention insulin resistance? This is a very good question and the reason for this episode. Most likely, your doctor actually suspects that you do have insulin resistance but holds the conventional view that insulin resistance is caused by weight gain.

And so, skips over the insulin resistance part and just tells you to lose weight thinking that is getting at the source of the problem. In fact, growing evidence suggests that insulin resistance is not caused by weight gain but the other way around. In other words, weight gain, specifically abdominal or visceral weight gain, is caused by insulin resistance.

So. Being told to “just lose weight” to fix the underlying metabolic problem that is causing you to gain weight is putting the cart before the horse. A better approach is to identify insulin resistance, and then work to lower insulin, which will improve metabolic function and have the side benefit of creating weight loss around the middle.

How do you identify insulin resistance?

Signs of insulin resistance include, as mentioned, fatty liver, weight gain in the upper body and around the middle, skin tags, and another skin condition called acanthosis nigricans, which is a darkening of the skin in the armpits and around the neck. Now, just to be clear, you can have insulin resistance without having those physical signs but if you do have those physical signs, it’s very likely you have insulin resistance. Blood tests that suggest (but not diagnose) insulin resistance include high triglycerides and high cholesterol. Which of course, means that reversing insulin resistance can be an excellent way to lower cholesterol.

The liver enzyme ALT and another test called c-reactive protein can be high with insulin resistance. And sometimes, blood glucose and hemoglobin A1C (or HbA1c) can be high. But quite often glucose and HbA1c are normal with mild to moderate insulin resistance. Which means that if your doctor only tested for glucose or HbA1c then she did not test for insulin resistance.

Instead, the test for insulin resistance is to test the hormone insulin. That can be done as a simple fasting insulin test, which just to say again, is different from a fasting glucose test. A more comprehensive test is the HOMA-IR index, which is a ratio of 3 fasting insulins to glucose. Then there is the glucose tolerance test with insulin, which is the test I use with my patients. And the one you could request from your doctor. Or you could request the HOMA-IR index test. The glucose tolerance test with insulin is the test where you do a fasting blood test and then test again at 1 and 2 hours after a glucose drink. Except this time, you’re testing not just glucose but also the hormone insulin fasting and then at 1 and 2 hours after the glucose drink.

A healthy fasting insulin should be less than 10 mIU/L or 60 pmol/L. Depending on the units. One and two hours after the glucose challenge, a healthy insulin should be less than 60 mIU/L or 410 pmol/L. Of course, it’s normal for insulin to rise after the glucose challenge and after a meal. That’s its job. And insulin at the right level has many benefits including entraining circadian rhythm, building muscle, and if you’re a young woman, keeping your period going.

But insulin that is above those reference ranges—either fasting or peak insulin—is high insulin or insulin resistance and is a problem. High insulin is both 1) a driver of weight gain, disease, and metabolic dysfunction, and 2) a biomarker of underlying metabolic cellular dysfunction.

But the good news is that it’s reversible. As insulin sensitivity improves, and insulin comes down, metabolic function is restored and weight loss can occur. In general, it’s probably not possible to lose much abdominal weight, or abdominal fat, until fasting insulin comes below 8 mIU/L, which can take several months depending on how high insulin was to start with. But the thing to understand is that you could be achieving significant metabolic improvement, Ie. reversing insulin resistance, for weeks or even months before you notice significant weight loss. Which means, you should not get discouraged if you don’t lose weight right away. As long as your insulin is coming down.

Insulin coming down means your metabolism is improving and you are setting yourself up for better health and future weight loss. Shortly, I’ll list some of the strategies for lowering insulin but please understand they all involve improving something called metabolic flexibility. Which is the ability to switch between burning glucose and burning fat. Most of which happens in the mitochondria. Which are the little intracellular factories, or what I called the metabolic nuts and bolts, that turn glucose and fat into energy. And you have quadrillions of mitochondria which are constantly being replenished so there’s lots of opportunity to make more and healthier mitochondria.

The biochemical connection between mitochondrial dysfunction and insulin resistance is a little complicated but it’s basically that when the mitochondria are overwhelmed by energy excess or other insult, they signal the rest of the cell including the insulin receptor to stop responding to insulin. Thereby temporarily stopping the flow of glucose to the mitochondria and temporarily sheltering the mitochondria from the reactive process of energy production. It’s explained in a quite famous paper called: “Insulin resistance is a cellular antioxidant defense mechanism.”

This, of course, raises the question of what causes the mitochondrial distress and therefore insulin resistance in the first place? It’s a big question and the answer is lots of things including energy excess, or overeating. But lots of other things. Other insults to mitochondria and insulin sensitivity include environmental toxins, medications, ultra-processed food, circadian disruption, sarcopenia, nutrient deficiency, neuroendocrine issues, chronic inflammation, and microbiome issues—just to name a few. And all those metabolic insults seem to be having an epigenetic or transgenerational effect which means that each of the last two to three generations is more prone to insulin resistance than the generation before. Which means your insulin resistance is a negative effect of your environment and/or your parents’ or grandparents’ environment. And not necessarily something you’ve done wrong.

At the same time, you can still make changes to reverse insulin resistance and regain a healthy metabolism.

A full discussion of all the strategies would be a 2-hour lecture. And this is just a bitesize podcast. So, I’m going to have to just list some of my favourite strategies. And if you want the details and citations, please check out my books, blog, and recent workshop.

And of course, you don’t have to employ all the strategies at the same time, especially not all the supplements. It’s just a quick survey or overview of some of the things that can work.

Here we go. Effective, evidence-based strategies for reversing insulin resistance include:

  • Moving the body to build muscle.
  • Eating enough protein.
  • Avoiding ultra-processed food, including what are called “acellular” carbohydrates.
  • Fixing any underlying gut problems because meta-inflammation from the gut can cause or worsen insulin resistance.
  • Supporting a healthy circadian rhythm with morning light and protein.
  • Eating at the same time every day, which also helps circadian rhythm.
  • Getting enough sleep.
  • Reducing stress and enhancing parasympathetic tone and heart rate variability.
  • Boosting oxytocin by, for example, getting a massage or spending time with friends.
  • If you’re a woman, maintaining a good level of estrogen and progesterone, which enhances insulin sensitivity.
  • And, if you’re a woman, not having too much testosterone, or not taking a progestin with a high androgen index, because too much testosterone can reduce insulin sensitivity.
  • If you’re a man, the opposite is true. Too little testosterone can reduce insulin sensitivity.

Other strategies include:

  • Gentle intermittent fasting, especially fasting overnight, which is called time-restricted eating.
  • Supplements such as magnesium, taurine, myo-inositol, berberine, silymarin, and choline. Silymarin and choline work primarily by improving fatty liver, and that brings us to the strategy of avoiding high-dose fructose.

By which I do not mean fresh fruit, but am referring to concentrated high dose fructose from things such as soft drinks, fruit juice, and desserts, even natural desserts. At high dose, above a certain threshold (which is different for every individual) fructose spills over from the gut to the liver where it can cause mitochondrial damage, fatty liver, and insulin resistance. At a lower dose, most fructose is converted in the gut to glucose and organic acids. And is fine and healthy. For the citations, see my fructose blog post.

A temporary low-carb or keto diet is another strategy, especially for more severe insulin resistance.

And finally, there are, of course, other non-insulin-resistance causes of weight gain which I’ll discuss in future episodes and on my blog.

Okay. I hope that’s been helpful and thanks so much for listening. Please share and leave a review. And I’ll see you next time when I’ll discuss how to improve premenstrual mood symptoms.

18 thoughts on “The Most Common Cause of Weight Gain”

  1. I recently saw a doctor for unexplained weight gain following a bout of Covid, despite little change in exercise or eating habits. The tests showed higher-but-normal blood pressure, blood glucose and hba1c levels; normal thyroid ranges; and optimal cholesterol levels. At 18 months postpartum and breastfeeding, I still have lactational amenorrhea, despite the weight gain over the past few months. Is shifting my diet to higher carb optimal for the resumption of ovulation? I’m worried that doing so will cause additional weight gain and potentially worsen blood sugar numbers, since I do not know if these numbers reflect prediabetic vs. adaptive glucose sparing conditions. Additionally, I already walk everywhere, eat plenty of protein, high magnesium foods, and do strength exercises several times a week. What are your thoughts?

  2. This has come at just the right time!! I’ve just started working with a naturopath as my weight gain has started to cause anxiety & stress, no matter how clean & whole I eat. I stopped drinking at the New Year & knew it would take months for my body to heal & recover, but really thought the weight would finally start coming off. I’ve increased my exercise, improved my sleep with magnesium & am meditating daily to help with anxiety. I’m going for blood tests later this month & will meet with the naturopath to review the results (many of the tests I’m having done you have listed! So I feel like I’m finally on the right path).
    I’m 47 & quite possibly not yet perimenopausal (but have felt like it for YEARS!!) & my aim is to educate myself & gather tools to help me through all this without further weight gain (50 pounds in 5 years… yup, awful!!).
    I’m going to do more reading on your blog… Thank you!!

  3. I think I became insulin resistant when I transitioned off birth control and started eating more dairy. I went from 127 to 135 in a month. I was so excited to start eating dairy after realizing my gut had made a huge turn around with probiotics bone broth and magnesium glycinate. I knew dairy was “okay” because I no longer broke out. In the past I had awful cystic acne with my period when I ate ice cream or drank milk. However I ate so much Greek yogurt and put whole milk in my coffee, too much natural sugar too quickly. No matter how much I walked I couldn’t drop the weight only in my mid section and thighs, but I thought I was eating healthy. I developed skin tags, had to wake up every night to pee. Terrible cramps too. Didn’t put it all together until the tags disappeared and I could sleep through the night.

    I switched to half and half, intermittent fast for 15-16 hours, pack my lunch everyday, over night oats as first meal, no more Greek yogurt daily, ice cream occasionally, inositol, probiotics, magnesium glycinate and zinc. I walk in the morning while fasting and incorporated daily salads back in to my diet. The intermittent fasting helped the most but I did not see real results until i consistently reach 15/16 hours. Back down to 127 for my lean 5’4” frame.

  4. When you’re insulin resistant you should also be paying attention to the glycemic index of what you eat and try to eat only low glycemic foods. All carbs eaten should be complex and slowly digesting carbs: whole-grain rice, wholemeal bread, wholemeal pasta etc.

  5. I gained 20 pounds, all in my midsection and hip area, since the beginning of c***d, just from stress eating and not being as active as I usually am. Magnesium has been great for me, along with daily walks and avoiding sugar.
    I’m 145 pounds now, so I’m still within my healthy weight range, but it was eye opening to see how much lack of movement and stress eating can make me gain weight so quick. I also struggle with hangry-ness and symptoms of reactive hypoglycemia.
    Is there a connection with reactive hypoglycemia and insulin resistance, and can the same things you suggested here help RH?

  6. Thanks Lara that’s great information. So should weight loss be easier if both are in balance? I haven’t lost anything its been 6 months now?

  7. Hi Lara, I’m wondering your thoughts on IR in menopause, I have gone back to HRT due to very low oestrogen, weight gain and terrible blood sugar and overactive stress response. I am feeling much better overall, but I’m not getting much help from doctors on what blood levels of oestrogen and progesterone should be? Different doctors different opinions. I feel like when progesterone is too high it exacerbates the IR is that correct? If so what should it be for continuous BHRT? I’m wanting to use as little as possible to gain the benefits. Thanks

    • As you say, different doctors have different opinions, but I personally do not think it is necessary or helpful to monitor hormone levels (blood or urine) when taking MHT. Of course, happy to have other opinions chime in here. Instead, the strategy is to use just enough estradiol to feel better and no more. Usually a 25 or 50 mcg patch. As for progesterone, I know it has the reputation of promoting insulin resistance, but clinically, it seems to promote weight loss in perimenopausal women and in menopausal women when combined with estrogen. And Prof Prior says that progesterone is good for insulin sensitivity (in part, because of its anti-androgen benefits), especially when in the presence of estradiol (either from the high estradiol of perimenopause or an estradiol patch).

    • Sorry, and meant to say: the majority of my patients do something like a 25 mcg estradiol patch plus 100 or 200 mg progesterone taken nightly 5 or 6 nights out of 7. Just to give a little break or “wash out” day from progesterone.

      • Hello Dr Lara! Thank you so much for these articles and blog posts as they are so very helpful. I’ve just started a very low dose of estradiol trans dermal patch but have been taking 100 mg progesterone daily for a couple years. I never knew we should take a break from it? Why is that? Now I’m afraid I may be taking too much? Also my fasting insulin is 6 but my fasting glucose is slightly high at 109 and A1C has always been normal but with last blood draw it was 5.8 which I know is too high. Very confused by these numbers.

      • Would that amount of progesterone 5 nights work with a higher estrogen dosage? Say 37.5 mcg – 50 mcg. I know if you have a uterus, you do need enough progesterone. I struggle with taking progesterone every day (7 days a week, every week), I think it starts causing side effects. Why do you think a wash out day or two is needed? (I think it’s needed but I would like some confirmation it isn’t only in my head, that it works better)

        The 25 mcg of estrogen really was low for me, was still having night sweats that disturb sleep. So I’m on 37.5 and wouldn’t even hesitate to do 50 if night sweats got bad but I may not need it.

  8. You are amazing!
    Tanks so much for the posting!
    Was very helpful. I think when a took dhea I noticed after while that my belly got fatter and strange ..
    Is that make sense?

    • This is really interesting. I have also noticed this and I take DHEA too (prescribed), but I have never made the connection. Would be interested in Laura’s thoughts about a possible connection.

      • Yes Josie.. my body got really weird after taking dhea … I don’t know if related with too much estrogen or too much testosterone..
        I read a post from Lara once that too much testosterone makes us fat..(belly especially).
        But too much estrogen accumulates fat too.
        I wonder one day know the real answer.
        Hormones is a delicate issue..

  9. Great information!

    I’m 44 years old and still on my period, I keep a pretty low weight and exercise and follow all your advices, so luckily I don’t have insulin resistance but I’m curious what “gentle intermittent fasting” is in your opinion?

    I’ve been doing it for ten years (mostly 18-6) and now everyone is very careful about recommending it to women (specially at my age) but really eating 3 meals a day (which is the maximum suggested lately) in a very long eating window is kind of hard for me. What’s your opinion about it? Fasting 14 hours throughout the month (that means follicular, ovulation, luteal and menstrual phases) is a good in-between, or should I stick to 12 hours?

    I have an endometrial polyp since many years (I remove it surgically but it appear again, in the same place!) who arrived just as I started doing the daily fasts and I really worry that evrything is connected.

    Thank you again for such valuable content!

    • Thanks for the question. I think some women can do shorter eating windows and longer overnight fasts. It really depends on the individual and factors like age, perimenopause status, chronotype, state of the nervous system, and severity of insulin resistance. And it can change over time. Basically, fasting is a little stressful and can be difficult for someone with quite impaired metabolic flexibility. So, long fasts are not recommended if there’s already anxiety or blood sugar crashes from fasting. Instead, women can start gently, focusing on protein in the morning and getting enough sleep, and work up to a longer overnight fast that feels good.

      I’m happy to have others chime in here.

      • When I first started fasting, I had difficulty making it even 12 hours, but now I can easily go 16 hours. I found having a spoonful of coconut oil and some salt helped me get over the hump.


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