Does Age Affect Your Metabolism?

Yes, age DOES affect your metabolism.

But probably not in the way you think.

My whole life I have heard people say that once you hit 30 your metabolism slows down. And it slows down even more at 40.

And then we hit 50 and for many women, all hell breaks loose.

But research around age and metabolism paints a different picture.

First of all, we are defining metabolism as how much total energy you spend each day.

This is influenced by not only age but also your size, your “fat-free mass” (muscles, bones, organs), your digestive activity, your unique metabolic makeup (genetics, etc), daily physical activity, immune function, and other variables.

When accounting for these factors research has shown that humans move through 4 distinct metabolic phases based on age.


Phase one is from infancy to 1 year old.

Phase two is from age 1-20.

Phase three is from age 20-60.

And phase four is beyond 60.

The research shows that from birth to age 1 the metabolism speeds up to about 50% above adults and then it slowly declines from age 1-20 and then levels off. From age 20 to 60 the amount of energy you spend daily is relatively stable (even during pregnancy and breastfeeding it stays pretty stable!). And then from around age 60 (in this study adults up to 90 years old were studied), the metabolism slowly declines. (1)

This flies in the face of common myths around metabolism.

Some of the decline in metabolism after age 60 is due to reduced fat-free mass (organs are smaller and less muscle mass) and some of it is due to less physical activity. But those factors don’t account for all of the decline.

So, yes, age does slow down our metabolism but not until after age 60-65.

This may sound depressing if you are over 60 but I would like to invite you to see this as an opportunity.

Some of the decline is due to less muscle. Strength training and eating sufficient protein can really help with this!

And if you are between the ages of 20 and 60 and you feel your metabolism is sluggish it is probably due to some other issue, not your age.

Either way, again, eating sufficient protein and building lean muscle tissue can help keep your metabolic activity robust.

So why do we see people putting on weight more easily after 30, 40, and 50?

I spend a lot of time thinking about this. Why would you not be losing weight even though you are in a calorie deficit? The answer is NOT to eat less food. That is for sure. And it's also not to just work out harder and longer.

I don't have the full answer, no one does right now. But when a person's metabolism is "sluggish" and not responding to the calories-in, calories-out model there are a few things to look at.

Most research points to chronic stress, chronic inflammation, reduced physical activity, and imbalanced hormone function. In addition, poor glucose and insulin regulation can adversely affect metabolism.

There is a way to address these issues and dieting is NOT THE ANSWER!

Rather the solution can be summed up in one phrase: “healing self-care”.

Healing self-care” means living your life with a gentle, loving approach that aims to heal the body.

— Jill Cruz

By being gentle and kind to ourselves.

By eating enough calories to sustain the basal metabolic rate (BMR) at LEAST.

By forgetting about carb counting and focusing on nutrition counting.

Are you getting enough vitamins and minerals from your food? You should be getting AT LEAST the RDA for all nutrients except for a few tough ones like Vitamin D.

Are you getting a bunch of polyphenols?

Are you eating enough protein?

And dieting, eating less, and working out like crazy is a miserable road to nowhere.

Metabolism age

An even when you’re not getting it just right or you are on the path to adding more healthy habits, be gentle to yourself for not having it all figured out right away.

So, for those of us under 65 or so, let’s stop blaming our age and start addressing the lifestyle factors that really matter.

For those over 65, I will invite you to do the same. Even if your metabolism is not as robust, all of those practices will make a difference and help you optimize cellular function.

In our WYN Program, you get the guidance and support you need to start developing the list of healthy habits that will keep your metabolism as balanced as it can be and to age with vitality and energy.

We provide you with the accountability you need to make progress in the 5 areas of health mentioned above:

  • Nutrition
  • Physical Activity
  • Sleep
  • Stress Management
  • Mindset

If you would like to learn more about our program I invite you to book a call with me. Just click below.


Pontzer H, Yamada Y, Sagayama H, Ainslie PN, Andersen LF, Anderson LJ, Arab L, Baddou I, Bedu-Addo K, Blaak EE, Blanc S, Bonomi AG, Bouten CVC, Bovet P, Buchowski MS, Butte NF, Camps SG, Close GL, Cooper JA, Cooper R, Das SK, Dugas LR, Ekelund U, Entringer S, Forrester T, Fudge BW, Goris AH, Gurven M, Hambly C, El Hamdouchi A, Hoos MB, Hu S, Joonas N, Joosen AM, Katzmarzyk P, Kempen KP, Kimura M, Kraus WE, Kushner RF, Lambert EV, Leonard WR, Lessan N, Martin C, Medin AC, Meijer EP, Morehen JC, Morton JP, Neuhouser ML, Nicklas TA, Ojiambo RM, Pietiläinen KH, Pitsiladis YP, Plange-Rhule J, Plasqui G, Prentice RL, Rabinovich RA, Racette SB, Raichlen DA, Ravussin E, Reynolds RM, Roberts SB, Schuit AJ, Sjödin AM, Stice E, Urlacher SS, Valenti G, Van Etten LM, Van Mil EA, Wells JCK, Wilson G, Wood BM, Yanovski J, Yoshida T, Zhang X, Murphy-Alford AJ, Loechl C, Luke AH, Rood J, Schoeller DA, Westerterp KR, Wong WW, Speakman JR; IAEA DLW Database Consortium. Daily energy expenditure through the human life course. Science. 2021 Aug 13;373(6556):808-812. doi: 10.1126/science.abe5017. PMID: 34385400; PMCID: PMC8370708.

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