Is Your Metabolism Slowing Down as You Age? The Surprising Answer
Welcome to this part of the internet where we consider how both lifestyle (nutrition, muscle building) AND hormone changes contribute to body composition changes in women in their 40s and 50s.
The online debates have been spicy lately, and I’ll get in the ring with some data and clinical insights to help you better understand your changing physiology. It is not simply calories in, calories out OR just hormones.
Turns out, like most things, the truth lies somewhere in the forgotten middle.
For decades now, women have been told to “suck it up buttercup” when it comes to body changes as we age:
“This is just part of aging.”
“This is your new normal.”
“Your metabolism isn’t what it used to be.”
Debates continue on the mechanism for excess and unwanted fat deposition for women in perimenopause and menopause. So many women in the Bettyverse have told me that despite dialing in nutrition and exercise they have continued to gain weight (usually through the midsection) DESPITE these efforts.
When we are told to simply eat fewer calories to compensate for the weight gain, or to increase our physical activity — this advice fails to encompass the totality of what is happening. It is part of it, but not all of it.
So is it metabolism? Is it hormones? What’s driving this persistent change in our body composition?
Metabolism — Does it Change With Age?
Conventional thinking tells us that as children, our metabolism is elevated and reaches a peak in our mid-20s. This does not seem to be true.
This study set out to investigate the effects of age, sex, and body composition on total body expenditure and other components of metabolism. It was a nice size (6421 participants, with 64% of them female) with geographically diverse backgrounds from 29 different countries. They looked at men and women from 8 days of age to 95 years old.
A few interesting trends emerge from this study.
- First: In the cohort of 20- to 60-year-olds, metabolism remains virtually unchanged. This remains true even during pregnancy! It is only around the 63-year-old mark that metabolism begins to decline.
- Second: The single biggest predictor of your metabolism is directly related to your fat-free mass. For an in-depth look at FFMI, listen to my Better! podcast conversation with Dr. Tommy Wood.
Both of these findings are great news for Bettys navigating perimenopause and menopause! Why? Because it gives us a sense of agency, at least partially, over our bodies in our 40s and 50s.
The biggest predictor of your metabolism is how much muscle tissue you have (and by way of extension your bone density). That IS something you can control. Type A personalities rejoice and say it with me, “WE CAN CONTROL SOMETHING!”
However, metabolism is only a part of body composition. How many calories burned is one thing, but fat distribution, type of fat accumulation, insulin resistance, and the loss of anabolic hormones (estradiol and testosterone) contributing to the loss of lean muscle mass is quite another.
During perimenopause and menopause, your tissues become more insulin resistant as a natural consequence of aging. This makes it harder for your cells, tissues, and organs to get the nutrients they need to produce energy.
We know that insulin resistance shows up in skeletal tissue for decades despite euglycemic levels. Said another way: Your muscles can be insulin resistant for YEARS and yet, you can have normal blood sugar because your pancreas can pump out more insulin to counteract the rising blood sugar levels.
The net effect of insulin resistance is fat production and accumulation in the liver (referred to as de novo lipogenesis) — also known as visceral fat. This is often the reason why women see their cholesterol levels skyrocket in perimenopause and menopause despite “doing everything the same.”
But wait, there’s more!
Declining estrogen levels during perimenopause are also part of the reason you see visceral fat distribution favored over subcutaneous fat deposition in your 40s and 50s.
The phenotype of fat literally changes during menopause where your body will preferentially begin to accumulate fat on your organs versus accumulating fat under your skin.
The fat under your skin is largely harmless despite your general disdain for it.
The fat that accumulates around your organs, however, has terrible consequences for your health including skyrocketing the development of cardiovascular disease, Alzheimer’s disease, type 2 Diabetes, cerebrovascular disease, and stroke.
There also is ample evidence that visceral fat is incredibly inflammatory. This leads to premature aging of your cells, tissues, and organs, and generally makes you feel awful.
So, you must consider BOTH lifestyle and hormonal interventions.
1. Consider the composition of your calories.
- In my book, The Betty Body, I detail a female–centric ketogenic diet for women looking to lose weight, and more specifically, lose visceral fat.
- The ketogenic diet ( high fat, moderate protein, and low carbohydrate) has been shown to improve all measures of body composition including body weight, body mass index, waist circumference, fat mass, fat–free mass, lean body mass, visceral adipose tissue, and body fat percentage
2. Lift heavy weights with the intention of putting on muscle mass.
- “Heavy” means different things to different people, but as a general guideline, the last few repetitions of a set should be very difficult.
- You should still be able to rep out good form, but the intensity should be an 8 or 9 out of 10. Forget 3 sets of 15.
- Work until the muscle is done like dinner.
3. Exercise snack your way through the day.
- I detailed the utility of exercise snacks and their benefits on lipids, body composition, and overall health here.
- We are designed to have a lot of low-grade activity throughout the day. If you are someone who sits at a desk for several hours a day, consider investing in an under-desk treadmill and a convertible desktop stand to be able to get some consistent walking through the day. It doesn’t need to be fast: 1.0–1.5 mph is plenty!
Hormone Replacement Therapy
- I’m a big fan of HRT, and think this can and should be started as soon as there is evidence your body is struggling to produce adequate levels of estrogen, progesterone, and testosterone.
- I always recommend getting blood work every six months to monitor your levels — or sooner if you think something is up.
- Consider starting HRT in perimenopause when things go awry and plan to be on them for the long haul.
- Don’t go it alone. Make the HRT decision in tandem with your doctor.
Bonus! Take a listen to my in-depth discussion about the Women’s Health Initiative and why it was a colossal failure for our beautiful menopausal women — check it out here.
- Pick up a copy of The Betty Body to learn how to apply the ketogenic diet as a mechanism to reduce body weight, body mass index, waist circumference, fat mass, visceral adipose tissue, body fat percentage, and increase fat–free mass and lean body mass.
- Book an appointment with your doctor to discuss HRT. At the very least, get some blood work done!
- Start lifting weights intending to increase muscle mass. Intensity is key here. Work the muscle close to (but not at) muscle failure. For most women, rate your set intensity between 8 or 9 out of 10.
QUESTION OF THE WEEK
Q: Post-workout soreness: How much is considered normal? (If any?)
This is a great question! I’m going to nerd out and break this down into the different components that might be contributing to your soreness. Let’s also look at whether or not they are “common” or “normal.” Much of it has to do with different fatigue types related to recovery.
Muscular Fatigue / Soreness
This is the soreness in the muscle/muscle groups you’ve trained.
There are many reasons for muscle soreness and fatigue. The most common one being a novel stimulus. If you went to the gym on Monday, found your groove, felt like Woman Woman, and decided to either change up some exercises in your routine and/or add weight to the exercises, this can elicit soreness in your muscles.
DOMS (delayed onset of muscle soreness) can occur up to 72 hours after the stimulus as the muscle tissue repairs and remodels itself.
This type of soreness is not required each time you train, but out of the different types I’m going to describe it is the most desirable one. If you trained your glutes on Monday, and on Tuesday your glutes are sore, it’s an indication that the novel stimulus has been directed at the target muscle group. If you’re sore in your biceps after training glutes, that’s a problem.
To develop strength (hypertrophy), you don’t always need to be sore. It is not an indication that you had a successful lifting session.
Said another way: If you’re NOT sore in your glutes on Tuesday when you trained them on Monday, it doesn’t necessarily mean nothing happened.
This is normal to feel or not to feel. I love it when I can feel some muscle soreness, but I don’t hinge the success of my lifting session based on it.
Joint, Tendon, Connective Tissue Fatigue / Soreness
This is soreness originating from the joints, connective tissues, or tendons.
We really want to minimize this type of soreness both during the workout and in the recovery period afterward. Feeling pain or soreness in these elements can indicate that there may be a technique issue with compensatory movement patterns present.
For example, you really shouldn’t feel pain in your shoulder joint when doing a side lateral raise, or pain in your knee when doing a squat. If you are, it is a possible indication of aberrant mechanics during the move itself. This partially translates the force to the non-contractile tissue. This could be muscle movement patterning, a lack of mobility at the joints themselves, or both. It could also be that for your biomechanics, that particular movement isn’t optimal for YOU. There are many other ways to shred your legs and grow your shoulders.
You want this type of fatigue and soreness to be as close to zero as possible. It is certainly not normal to be feeling this kind of soreness all the time.
Axial Fatigue / Soreness
This is the fatigue and soreness through the spine and back from spinal loading.
It’s anything that loads weight on your spine top to bottom (e.g., putting a barbell on your back) or from hinge movements like a deadlift where a lot of the lower, mid, and upper back muscles, as well as the deep muscles of the back, are involved in stabilizing and executing the movement.
While not inherently good or bad, we want to be mindful of excessive axial loading being the limiting factor in lower limb progression.
For example, when I’m training my legs, I have to be mindful in between sets that both legs are sufficiently recovered AS WELL AS my lower back before I start again. My glutes can be ready, but if my lower back still needs a minute I wait until any secondary mover (in this example my lower back) is ready again. Otherwise, it’s going to be my back that limits my execution, energy, and form on the next set.
Your back is designed to carry heavy loads and with training, you will necessarily experience some axial loading. Fatigue is normal.
Ensure you’re 1) giving yourself sufficient rest in between sets, and 2) giving yourself adequate time between leg days.
Overall or Systemic Fatigue
This is the fatigue that occurs after too many days of poor recovery. It can be many weeks or months before you feel the effects.
You might notice that you begin to experience brain fog after workouts, or you’re generally less excited about training in general.
Other markers like poor sleep, excess or prolonged soreness, or any other types of fatigue above are beyond what you would consider normal.
This lack of desire when you have been able to demonstrate a consistent training schedule in the past is usually a gentle reminder to take a break.
A lot of women dealing with autoimmune conditions might experience systemic fatigue when they have pushed it too far in the gym. Learning how to stimulate — not annihilate — your muscles when dealing with an autoimmune condition might be tricky, but it’s fundamental to train at 40–50% less capacity so you don’t overwhelm an already overwhelmed immune system.
When you experience overall fatigue like this, it might be time for a deload week (another topic I will be exploring), or taking a few days off altogether.
What I Recommend: LMNT
Because you lose water and sodium when you sweat, you have to replace it. The water? Pretty easy. The sodium? It’s got to be the right kind of electrolyte mix. LMNT combines sodium, potassium, and magnesium. This trio helps prevent muscle cramps, headaches, and energy dips.
For my Bettys in a cold climate, your hydration needs go up in winter. And while I’m truly a fan of LMNT’s limited-edition Chocolate Medley for hot drinks, the Chocolate Mint was a surprise. (I actually don’t like chocolate mint anything.) I wanted give it a fair shot, though, and ended up loving the taste. I mixed it with hot water. Super simple and the perfect complement to a snowy day at home this past week.
For my Bettys in a hotter climate, you’ll want to try the Watermelon for some refreshingly fruity, zero-sugar hydration.
When you go to drinklmnt.com/drestima, you’ll get a free LMNT Sample Pack of flavors with your order. I know you all love recipes, so be sure to visit LMNT’s “Recipes” section for some salty inspo.
HEALTH TOOLKIT: I’ve put together a toolkit for you on my brand new website. I designed these resources for my Bettys who are menstruating, experiencing perimenopause or have gone through menopause. There are commonalities between the categories and also specifics for each one. Everything I recommend, I use myself. That’s my rule. I invite you to take a look!