Active discussions

Please or to access all these features

Talk
AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

How does our metabolism slow down so much

31 replies

Flufffluff11 · 19/09/2026 20:07

I remember when I was a teenager. I would eat Crisps and chocolate every lunch, and pizza and chips every evening. It was a Fast food house which is a bit neglectful, but understandable at my mum was a struggling single mum, that was how it was.

I was so thin all through my teens

Now I'm early forties. I eat pretty healthily. I go to the gym three times a week, yet I'm overweight and it takes so long for me to lose a pound.

How does age slow down metabolism so much? Agh

OP posts:
Trumptontown · 19/09/2026 20:12

I don’t know but I imagine, in part, it’s loss of muscle mass which we lose as we age if we don’t strength train.

Original poster
Flufffluff11 · 19/09/2026 20:18

It's taken me 4 weeks to lose a pound

OP posts:
MabelMarple · 19/09/2026 20:22

I don't think it does for everyone. I was lighter in my teens and early 20s but nothing really changed for me after my mid 20s. I'm 68 now and menopause made no difference, I weigh the same as I did 40 years ago. I don't diet but probably drink less alcohol than in my 20s.

DrumsPleaseFab · 19/09/2026 20:28

I think dieting is too hard so I have been focusing the last 5 years on building muscle and fitness. The fatloss then sort of falls into place

i have lost no weight as such, but much more muscle 5 yrs in even than I had in my youth

as a result I can eat quite a lot more

i think diets and restrictions are no way to live, but saying that I do about 15k steps a day and do gym 5X a week. It is a bit of a commitment and was only able to put so much time into myself and my health once kids were older teens

DrumsPleaseFab · 19/09/2026 20:28

BMI 23 so that is good enough for me

Sunsara · 19/09/2026 20:32

It really doesn’t. Look at the evidence. It’s your TDEE that’s dropped because you’re more sedentary.

LuckyHazelFox · 19/09/2026 20:34

One word - estrogen. It's fucked up by the menopause.

Original poster
Flufffluff11 · 19/09/2026 20:34

Sunsara · 19/09/2026 20:32

It really doesn’t. Look at the evidence. It’s your TDEE that’s dropped because you’re more sedentary.

I go to the gym three times a week and do cardio. I walk to work every day my job involves walking around.

I didn't go to the gym when I was a teenager and I sat at a desk for most of the day

OP posts:
JohnnyMcGrathSaysFuckOff · 19/09/2026 20:37

But cardio won't help.

What are you doing at the gym? Lifting heavy, bodyweight, jumping?

If you are not doing weights plus some form of plyometrics that is likely why.

Musicaltheatremum · 19/09/2026 20:38

You lose muscle bulk from 30s onwards so you burn fewer calories.

Original poster
Flufffluff11 · 19/09/2026 20:38

JohnnyMcGrathSaysFuckOff · 19/09/2026 20:37

But cardio won't help.

What are you doing at the gym? Lifting heavy, bodyweight, jumping?

If you are not doing weights plus some form of plyometrics that is likely why.

Cardio burns calories.

I do weights as well.

OP posts:
Catza · 19/09/2026 20:47

I hear what you are saying but you literally move less as an adult. Teenagers don't sit still. They fidget, they walk faster moving between classrooms, they go to parties, dance the night away, kiss boys, throw paper airplanes across the classroom and whatever else teenagers do. Plus, as a teenager your body and brain still develops and it takes a lot of resources.
Yes, you may be going to the gym (which, honestly, does not burn as many calories as people think) but you move a lot less overall throughout daily life. I don't mean purposeful movement either. It's all those incidental movements throughout the day.
A study published in 2021 looked at metabolism across lifespan
www.science.org/doi/10.1126/science.abe5017

Disturbia81 · 19/09/2026 20:50

you just have to eat very healthily and exercise with weights, I don’t put weight on easier now

JohnnyMcGrathSaysFuckOff · 20/09/2026 14:59

Yes OP but your metabolism is not a straight in/out mechanism like a bank account, right. It's not like you eat 100 calories and then do the stepper and burn off that amount and then it's like you never ate it. You need to increase your overall metabolism by having more muscle.

When you say you do weights, what? You need to be doing enough to change your body composition. So, lifting weights that are properly challenging, and plyometrics such as jumping, box jumping, or other explosive movements with impact.

A really good person here is Stacey Sims and her book Next Level which is specifically about middle aged women.

I'm not trying to be difficult, just helpful, honest!

Whenthecriwdsayno · 20/09/2026 15:00

for me it was childbirth as my teenage metabolism went when I had children which was at 17. That youthful part of my life was cut short.

Pinkfluffypencilcase · 20/09/2026 15:02

Is it as simple as building more muscle increases your metabolism?

pinkishtongue · 20/09/2026 15:05

Tell me about it. I eat cleaner than I ever have and exercise daily so although I’m quite strong and fit for my age I’m still chunky.

Original poster
Flufffluff11 · 20/09/2026 15:06

JohnnyMcGrathSaysFuckOff · 20/09/2026 14:59

Yes OP but your metabolism is not a straight in/out mechanism like a bank account, right. It's not like you eat 100 calories and then do the stepper and burn off that amount and then it's like you never ate it. You need to increase your overall metabolism by having more muscle.

When you say you do weights, what? You need to be doing enough to change your body composition. So, lifting weights that are properly challenging, and plyometrics such as jumping, box jumping, or other explosive movements with impact.

A really good person here is Stacey Sims and her book Next Level which is specifically about middle aged women.

I'm not trying to be difficult, just helpful, honest!

Okay thanks for explaining. I understand. That is useful to know. So I need more muscle.

At the moment with weights i am am doing

3 times a week -
6 bicep curls both sides with a 3kg weight.
6 lunges each side holding 3kg weights in each hand.
6 squats holding a 3 kg weight

OP posts:
likelysuspect · 20/09/2026 15:08

Its a bastard thats for sure. And since Ive been on HRT and AD's Ive put on a stone!!!

Trumptontown · 20/09/2026 15:13

Flufffluff11 · 20/09/2026 15:06

Okay thanks for explaining. I understand. That is useful to know. So I need more muscle.

At the moment with weights i am am doing

3 times a week -
6 bicep curls both sides with a 3kg weight.
6 lunges each side holding 3kg weights in each hand.
6 squats holding a 3 kg weight

Show quote history

Your answer is right here. You need to be doing at least 3 rounds, and as heavy as you can go (so if you can do more than 6-8 of each, go higher). Do compound exercises like back squats and deadlifts and a lot more variety than you’re doing now.

UniquePinkSwan · 20/09/2026 15:16

It doesn’t. People just get more lax. You need to strength train.

BeFairOliveBear · 20/09/2026 15:21

JohnnyMcGrathSaysFuckOff · 20/09/2026 14:59

Yes OP but your metabolism is not a straight in/out mechanism like a bank account, right. It's not like you eat 100 calories and then do the stepper and burn off that amount and then it's like you never ate it. You need to increase your overall metabolism by having more muscle.

When you say you do weights, what? You need to be doing enough to change your body composition. So, lifting weights that are properly challenging, and plyometrics such as jumping, box jumping, or other explosive movements with impact.

A really good person here is Stacey Sims and her book Next Level which is specifically about middle aged women.

I'm not trying to be difficult, just helpful, honest!

I thought it was calories, if I eat over maintenence I gain, below I lose. Is this not correct?

Original poster
Flufffluff11 · 20/09/2026 15:22

Trumptontown · 20/09/2026 15:13

Your answer is right here. You need to be doing at least 3 rounds, and as heavy as you can go (so if you can do more than 6-8 of each, go higher). Do compound exercises like back squats and deadlifts and a lot more variety than you’re doing now.

Show quote history

Sorry to add more health information. I have a ruptured disc in my back so I am nervous of doing more weights than I am doing. Apparently the rupture is small but it stopped me from walking entirely one day. I couldn't get out of bed. I couldn't make one step in front of the other without agony. I had to use a Walker all day. Medication helped. Im afraid to lift anything too much since

OP posts:
MeowDoku · 20/09/2026 15:24

Some of us have never been able to eat junk food/what we like without gaining weight, be glad for the years you could

Trumptontown · 20/09/2026 15:32

Flufffluff11 · 20/09/2026 15:22

Sorry to add more health information. I have a ruptured disc in my back so I am nervous of doing more weights than I am doing. Apparently the rupture is small but it stopped me from walking entirely one day. I couldn't get out of bed. I couldn't make one step in front of the other without agony. I had to use a Walker all day. Medication helped. Im afraid to lift anything too much since

Edited
Show quote history

So do I. Weight training has helped. Can you afford a PT for a block of sessions? They’ll really help build your confidence in yourself and what you’re able to do.