"Metabolic damage" and "metabolic adaptation" are probably terms you've heard floating around the fitness industry as of late. They are typically used when referring to the physiological adaptations that take place when someone is in too great of an intended calorie deficit for too long. This deficit can be from reduced calorie intake, increased calorie expenditure via exercise, or a combination of the two.
(Note: I use the word intended carefully because at some point, as your metabolism adapts, your deficit is no longer a deficit. Which is exactly what I'm going to cover below.)
Personally, I call this phenomenon a "metabolic shift" because I think it's important that we remove the fear of permanence in regards to what has happened. It's important to me that women don't think of themselves as broken or damaged, and that they recognize that only some of these shifts are permanent some of the time.
Now that that is cleared up, let's discuss.
Does this phenomenon exist?
What exactly is happening here, and why?
And more importantly, what can we do about it?
First and foremost, in my experience, these metabolic shifts absolutely exist.
"Dieting" (for most of us) means "a lot less food, and a lot more gym," (namely, cardio) and it seems to be our default when it comes to weight loss. Sure, we may acknowledge that strength training is important, and we might have some grasp on our hormones' roles and functions, but we are conditioned to go back to this extreme "solution" in desperate times, because after all, a calorie deficit is what's most important, right?
And if a little is good, then a lot must be better. So instead of a small deficit, we strive to create a massive deficit for (what we believe to be) faster results.
With or without results, many of us have playing this game with our bodies for quite a while. Personally, I started dieting in high school. I know some women who started even younger.
Years of serial dieting, slashing calories, and managing everything (from stress to guilt after eating something we deem “bad”) with food restriction and another punishing mile on the treadmill have left us in a bad spot. Not only is it nearly impossible to maintain, but we're often not getting any results, and it makes it too easy to feel like we’re racking up one more “failure” that leaves us wondering,
“What’s wrong with me? I'm exercising like crazy, and hardly eating anything. Why can't I lose weight?”
And while the psychological toll of dieting is huge, that’s a subject for another blog. Today I want to focus on the toll it takes on your hormones and metabolic rate.
To be clear, your "metabolism" isn't one static thing in your body. It's not an organ or a muscle.
Your metabolism is the orchestration of hormones and a host of processes, including releasing stored fat and then burning that fat or re-storing it.
And the problem starts with something you’ve heard a hundred times: we’re hard-wired for stress and survival.
Our body’s natural inclination is to "store up" for tough times, especially if we've experienced a prolonged calorie deficit. We have to fight that inclination daily given the unrelenting stress we're under, and readily-available, calorie-dense food of our modern world. We know all of this, of course, yet years of diet marketing still lures us toward killing ourselves in the gym day in and day out, and slashing calories to rock-bottom to drop those excess pounds. But our hormones have other plans.
Don't get me wrong. It is true that calories matter. Of course they do! No doubt that you have to create a caloric deficit in order to lose some weight. That much we know. But hormones matter too, and they matter a whole lot if you’re like the women who fill my practice, who are all wondering, “Why aren't my diet and exercise plan working? What’s wrong with my metabolism?”
We’ve been told to think of our metabolism as a simple math equation: calories in – calories out = weight loss. It makes more sense to acknowledge that our metabolism and hormones are fluid, dynamic, and adaptive. More like a rubberband. You can pull or push, but only to a point, then it snaps back (or it breaks altogether).
Calories matter, and so do hormones like insulin when it comes to losing weight. But let those ideas go for a moment and just think of the rubber band analogy. In order to get a result, weight loss in this case, you have to put just enough stress on it to get movement without it snapping back. The key is just enough. Not enough stress and you stay stuck. Too much stress, and like the rubber band, the metabolism springs back.
The spring-back happens in two stages, in my experience. One happens quickly, and you can remedy it by lessening the stress. The other happens as we yo-yo diet (or what I call the “digging your own grave diet”). This is when we just keep digging ourselves in deeper with more restriction and more exercise. I went through this big-time while writing my book Ultimate You. I know many of you have been there too.
Initially, when there is the wrong kind of stress (or too much stress overall) on the metabolism, the body simply adapts to the new stress by down-regulating the metabolic rate. You see this time and time again when you start a new diet or increase your exercise and get results for like a week, then nada. You’ve checked and double-checked My Fitness Pal, and it says you're in a deficit. But with this down-regulation of your metabolism (that can happen very quickly) you simply aren’t burning as much as you think you are.
Most research shows us that this adaptation is to the tune of 300–500 calories — meaning if you think your total daily energy expenditure (TDEE) is 2,200 and you shave off 500 calories, you may only be shaving off 300 calories because your TDEE has dropped. Of course, you throw in other hormone imbalances like insulin resistance, adrenal stress, or low thyroid, and you could be burning even less than that.
How do you know when this is happening? I always say you can tell when your hormones hate your plan. Appetite and cravings go up, energy goes down, and success goes out the window. (I use the acronym ACES with my patients to remind them of this.) During this initial slow-down the hormones that jump in to thwart your efforts are primarily leptin, thyroid, and cortisol.
You cut those calories or try to burn more off at the gym, and that triggers lower leptin levels and higher cortisol levels, which bring on the cravings for the carbs and sometimes fatty/starchy foods. This makes it extra hard to stick with your plan.
What this looks like for many of us is “clean eating" Monday to Friday and then bingeing on the weekend. For others it’s one to two weeks of dieting only to give into the cravings and get off track for weeks to months thinking, “Why bother — nothing works!”
If this sounds like you, just listen to those hormones talking by way of appetite, cravings, and energy. Make adjustments to ease up on the exercise or increase the calories a bit to create less stress on the metabolic rubber band.
It sounds simple enough. But I know there are many women who will fight it and do what I've done: dig our own grave deeper and deeper. We frustratingly look at the lack of progress and think, “I need to work harder.” So we keep going with a plan that our hormones hate, and white-knuckle it through the sugar cravings, fatigue and depression of it all thinking, “If I can just keep trying...”
When we do this we enter the second stage of dieting damage: hormone and immune system trouble. This is where women start to wonder if their metabolism is damaged or broken. Here are the big hormonal shifts that happen when we put too much stress on the metabolic rubber band:
This stress hormone comes into play when the stress of your diet gets to be too much. Initially stress hormones are high throughout the day, but in time they can become deregulated—high at the wrong times of day, low at the wrong times of day, or even low overall. Cortisol gets tangled up with insulin quickly as your blood sugar bounces from high to low and you wage a battle with your appetite, cravings and energy. Sleep often takes a hit due to cortisol irregularities as well, making it difficult to fall asleep or stay asleep. (More on that here.)
Cutting calories too low — and, for some, cutting carbs specifically — can really impact active thyroid hormone (T3) levels and can increase inactive hormone levels. Reverse T3 can rise in part due to cortisol/stress of dieting, as well as issues with the appetite-controlling hormone leptin. (See one such study here.) Thyroid gets involved right from the start as leptin starts to take a dive. In time, low thyroid can linger as a result of dietary restriction. See this study here.
With long-term stress of any kind, in this case dieting, progesterone takes the fall first. You’ll see breakouts, worsening PMS and for many women, longer cycles or disappearing cycles. Estrogen quickly becomes the dominant of the two and creates a bigger fat loss battle, especially in the hips and thighs. However in time, estrogen falls too and your cycle goes bye-bye entirely. You start having a very difficult time with fat loss, particularly around the middle.
If you're just in the first stage of this shift, then everything I’ve mentioned above can be corrected when you find the right amount of stress to put on the metabolism to get results but not push it so far that it snaps back at you.
(Keep in mind that the recommendations listed below are generalities based on patients I've worked with, but people and metabolisms are unique, so you need to pay close attention to your individual results and adjust accordingly.)
Step 1: Dial back exercise. First, cut back on the metabolic conditioning and long-duration cardio. You don't have to quit these things entirely right away. A good strategy is to to cut what you're doing in half every two weeks or so, monitoring your results as you go along. Continue doing some strength training (2–3 days a week works well for most), as it will help maintain your muscle mass through all this stress, and you can also do light, restorative walking.
Step 2: Next, play with your macros. Often, increasing carbs just a touch is enough. Start slowly by increasing your carbs by 10–20% every 2–3 weeks. If you haven't noticed a difference in 4–6 weeks, you may need Step 3.
Step 3: Finally, you may need more calories altogether, which I know goes counter to everything you’ve been taught, but try it. What do you have to lose? I generally have patients increase their overall calories by ~10% every 2–3 weeks, monitoring results as they go.
Often times these steps allow patients to start losing weight again right off the bat, but sometimes, they do experience a period of weight gain before they start losing. PLEASE don't let this freak you out. Think about this: if you you're currently doing isn't working — what are your other options? Continue dropping calories until you're only eating 500 a day and still not seeing results? I hope not.
If you’ve entered the second stage of these metabolic shifts, I’ll be honest — you’ve got a little more work to do. At this point, a targeted supplement plan can help those hormones get back into balance.
For starters, consider some adrenal adaptogens like ashwaganda and rhodiola. And replace the vitamins that get depleted during all this: magnesium, B vitamins, essential fatty acids, and antioxidants. Often other nutritional issues arise as well, such as anemia or digestive issues like hyper-permeability of the intestines and food sensitivities arise. Those must be fixed in order to get out of these shifts.
In some cases, there is a third stage, where more permanent issues take hold. For example, if the stresses mentioned above are significant enough, they can trigger an autoimmune illness such as Hashimoto’s. We can manage this, but we can’t go back and un-flip the switch.
The hormonal shifts above can be significant enough to trigger some vicious cycles of hormone resistance that can be very difficult to undo. For example, with cortisol activation from the stress of dieting, insulin resistance is often quick to follow. Some women will be more sensitive to this and develop elevated testosterone leading to breakouts, erratic cycles, etc. The insulin resistance adds to the leptin resistance, keeping appetite and cravings high.
The up and down blood sugar stress adds to inflammation, which creates more stress, and on and on that cycle goes. Meanwhile, in the background, more problems arise with digestion and intestinal permeability, which adds to inflammation, making insulin resistance worse.
As you can see, making things better may take some time, and the more advanced the shifts have become, the harder it can be to calm things down.
But don’t stress. Try some of the strategies and nutrients mentioned above. Make some changes to your exercise plan, take another pass at nutrition, and get help if you think you’ve shifted in a way you’re struggling to undo. You can always contact me ([email protected]) or find a functional medicine doc in your area.
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