Meet the Other Phone. Child-safe in minutes.

Meet the Other Phone.
Child-safe in minutes.

Buy now

Please or to access all these features

AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

[TW] I think I’ve messed up my metabolism with a very low calorie diet

58 replies

Koyo · 27/05/2025 13:06

Sorry I am posting for traffic. Posted on Weight Loss chat but didn’t get a reply

So I lost a lot of weight doing 800 fast. I was extremely depressed and had become a social hermit due to embarrassment over my weight. I did the low calories diet for 12 weeks. I lost three stone relatively quickly.

But now whenever I eat over 1000 calories I GAIN weight.

I assume it is due to my metabolism having slowed right down. I’m still glad I lost the weight as I feel so less self conscious.

Please share any advice on how to kick start my metabolism?

I do around 45 mins of brisk walking a day. I do plan to go to the gym this week for the first time. An amazing feat if you knew me. My family are very proud.

But I’m quite stressed about what my my body is doing.

OP posts:
dogcatkitten · 27/05/2025 13:08

You are probably mis-calculating calories, just eat an amount that keeps your weight stable, forget about the calories.

Koyo · 27/05/2025 13:09

I always assumed starvation mode was a made up thing.

I absolutely did not go over 1000 calories when I increased my diet and for the one week and I gained weight. Should not be possible!

OP posts:
Koyo · 27/05/2025 13:10

dogcatkitten · 27/05/2025 13:08

You are probably mis-calculating calories, just eat an amount that keeps your weight stable, forget about the calories.

100% did not snack and ate a weight loss ready made meal and hard boiled eggs. I was very very rigid.

OP posts:
Iwrotethelyricstoaxlf · 27/05/2025 13:11

What’s your bmr and TDEE

And are you 100% on your calories?

andtheworldrollson · 27/05/2025 13:12

This reply has been deleted

Message deleted by MNHQ. Here's a link to our Talk Guidelines.

andtheworldrollson · 27/05/2025 13:13

Ready meals often contain lots of bad stuff or too much salt which can affect things like water retention

Iwrotethelyricstoaxlf · 27/05/2025 13:13

You need the variety in calories also.

DH has been eating rigidly, but drastically cut carbs to below the recommended and could not shift the weight. He did put on.

Nows he’s joggers his macros around he can eat more and still lose (and not be a miserable carb deprived person)

Lanzarotelady · 27/05/2025 13:14

Why does this need a trigger warning?

ButterBites · 27/05/2025 13:15

Unfortunately this is why very low calories are not beneficial in the long term - it can slow down your metabolism.

Now that you’ve lost the weight you need to increase your calorie intake to a happy medium and maintain that, together with exercise.

Koyo · 27/05/2025 13:16

I wouldn’t have believed it myself. But I ate one ready meal (from a diet service) and two hard boiled eggs for a week and gained weight!

No snacks whatsoever. Only water.

The weight was falling off on the fast 800 for the first 10 weeks. Then in the last two weeks it slowed right down. I ate pretty much the same things. And am still overweight.

OP posts:
Mew2 · 27/05/2025 13:16

Yes you absolutely can slow your metabolism by too low calories- also the less you weigh the harder losing weight can be. And I would be looking at long term- feel better, look better, perform better. Have you measured and what do they show
However gaining weight is a tricky one- it could be water weight as often when you eat more your body absorbs more water
I would look at uping your drinking- again too little can increase your water weight
And then looking at increasing metabolism- HIIT style exercises are often most effective.... so bursts of high intensity exercise and a rest
You don't need to go to the gym to do it- you can do exercise at home with little equipment in front of you tube. If you go to a gym please see someone for an induction so you know what you are doing

Sugarnspicenallthingsnaice · 27/05/2025 13:16

You increase your metabolism by increasing your muscle mass.

Needspaceforlego · 27/05/2025 13:17

andtheworldrollson · 27/05/2025 13:13

Ready meals often contain lots of bad stuff or too much salt which can affect things like water retention

I think that will be the answer.
You must be retaining water.

I can go out for dinner and be more than a pound heavier the next morning, just to loose it again a few days later.
It has to be salt and water.

I'll also say time of the month can make a difference too.

Koyo · 27/05/2025 13:18

Sugarnspicenallthingsnaice · 27/05/2025 13:16

You increase your metabolism by increasing your muscle mass.

I’m going to start going to the gym for that reason. It’s the only thing I can see helping.

OP posts:
Koyo · 27/05/2025 13:20

Mew2 · 27/05/2025 13:16

Yes you absolutely can slow your metabolism by too low calories- also the less you weigh the harder losing weight can be. And I would be looking at long term- feel better, look better, perform better. Have you measured and what do they show
However gaining weight is a tricky one- it could be water weight as often when you eat more your body absorbs more water
I would look at uping your drinking- again too little can increase your water weight
And then looking at increasing metabolism- HIIT style exercises are often most effective.... so bursts of high intensity exercise and a rest
You don't need to go to the gym to do it- you can do exercise at home with little equipment in front of you tube. If you go to a gym please see someone for an induction so you know what you are doing

I have asked my BIL (a gym rat) to take me to the gym and just give me some pointers on some machines.

I am by no means doing this perfectly. I was extremely depressed. I made a change. And I’m glad I did. I am so much happier.

But yes, this plan is far from perfect

OP posts:
Koyo · 27/05/2025 13:21

Lanzarotelady · 27/05/2025 13:14

Why does this need a trigger warning?

Low calories can be triggering I thought

OP posts:
FortyElephants · 27/05/2025 13:25

If the weight gain has been over one week of increased calories then it's almost certainly water weight.

Koyo · 27/05/2025 13:28

FortyElephants · 27/05/2025 13:25

If the weight gain has been over one week of increased calories then it's almost certainly water weight.

But I think my metabolism had slowed because I was only losing a third of what I was losing even compared to just two weeks ago.

The weight loss was very very consistent and then it just fell off a cliff at around 10 weeks. And stayed pretty level. I increased calories as a direct consequence of this. I thought it would help.

I just don’t know how many calories to eat now 😢. I’m quite stressed about it.

OP posts:
Koyo · 27/05/2025 13:28

I still have about 30 pounds to lose.

OP posts:
MauraLabingi · 27/05/2025 13:29

If I 'diet' I lose weight, then when I stop I immediately gain two pounds or so. Water weight I'm guessing as a pp said. After a week or so it stops going up and maintains at that slightly higher weight. Is this what's happened?

If not, and you mean you've put on a lot of weight over a longer period, then yes, your idea of exercise (especially HIIT) is the best way to rev metabolism.

FortyElephants · 27/05/2025 13:30

Koyo · 27/05/2025 13:28

I still have about 30 pounds to lose.

To get where? Top of BMI or your own ideal weight?

You need to work out your TDEE and deduct 500 calories. Start there.

maddening · 27/05/2025 13:30

dogcatkitten · 27/05/2025 13:08

You are probably mis-calculating calories, just eat an amount that keeps your weight stable, forget about the calories.

There are some of us who cannot eat many calories without weight gain - it is not always the case that a person us just accidentally eating too much

Koyo · 27/05/2025 13:31

I’ve used chat gpt to calculate my bmr and tdee. Mathematically I am doing the right thing.

OP posts:
MauraLabingi · 27/05/2025 13:31

Ah cross posted. So you experienced a plateau whilst still on the LCD? This is completely normal. Weight loss is not linear. Plateaus are to be expected. You just keep on going if you are certain you are in a deficit and at some point the weight drops again.

Koyo · 27/05/2025 13:32

FortyElephants · 27/05/2025 13:30

To get where? Top of BMI or your own ideal weight?

You need to work out your TDEE and deduct 500 calories. Start there.

To be well into the normal weight range.

OP posts:
Swipe left for the next trending thread