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Weight loss injections/treatments

Discuss weight-loss injections and treatments, including personal experiences. Mumsnet hasn't checked the qualifications of anyone posting here. You may wish to speak to a medical professional before starting any treatments.

Weight gain after Mounjaro

72 replies

Liambro · 05/04/2026 08:59

So like many, I gave in to Mounjaro after years of failed dieting and it worked! 3 stone down and changed my mindset about food. However, once I came off it the weight has piled back on! I’ve gained almost a stone in just over a month despite only having 16000 calories a day (I use an app to track calories) has anyone else had this? I’m worried that in a couple of months I’m going to have gained all the weight back! I exercise and don’t snack and I’m literally putting on 3/4 lbs a week! Any tips? I can’t afford to go back on it, has anyone else experienced this and the weight has calmed down, I’ve gone down to 1400/1200 calories now but it’s hard to maintain and I’m worried that once I go back up I’ll just put more weight on. Any advice would be appreciated.

OP posts:
Wildgoat · 06/04/2026 08:50

Perfect28 · 06/04/2026 06:52

Sounds like you weren't obese to begin with OP? So you bought the jabs privately?

Huh? She’s 5ft 3 and weighed 11 stone 10 when she started, if she lost 3 stone to get to 8.10. Which gave her a bmi of just over 29. Over weight is 25. Obese is 30, you can get the jabs from bmi 27 with any health issues.

so yeah, she was bordering obese and nearly everyone buys them privately, the nhs only prescribe to a tiny amount of people.

Clearingaspace · 06/04/2026 10:01

Dragonscaledaisy · 06/04/2026 07:54

I've worked on tirzepatide for years and we have evidence from patients demonstrating gains - these are not patients newly initiating treatment. However, as I said, we'll agree to differ.

Can you describe what they were doing to achieve this please? Seems like this is what people need to do.

RoseField1 · 06/04/2026 10:46

Dragonscaledaisy · 06/04/2026 07:54

I've worked on tirzepatide for years and we have evidence from patients demonstrating gains - these are not patients newly initiating treatment. However, as I said, we'll agree to differ.

You've worked in the field of tirzepatide research for years with a cohort where you have access to their dexa scan data and in sufficient numbers to claim that as widely repeatable fact that people can and do gain muscle in calorie deficit over a long period of time? Really?
Whether a person is taking a GLP1 to lose weight or otherwise, if they are in long term calorie deficit they cannot build new muscle in any demonstrable amounts. That's settled science. Body recomposition is a different issue.

Mysticmaiden · 06/04/2026 12:31

THisbackwithavengeance · 06/04/2026 08:15

I don’t understand how so many on here are eating concentration camp level daily calories merely in order not to gain weight. Have we fucked up our metabolisms with constant dieting?

If the OP is gaining large amounts of weight on just 1600 daily calories, then something is wrong and I would be seeing my GP.

Are you for real? My tdee is 1490 currently, yes I would gain on 1600 and no need to add a comment about concentration camps, highly insensitive and offensive. What went on in there was abhorrent, they were literally tortured and starved to death, do you think they had the luxury to eat 1600 a day?
Maybe do some research on height, age, weight, ethnicity and metabolic issues and how it affects tdee. Not everyone is tall and young. I'm actually enjoying maintaining on 1400, it's a luxury compared to having to eat 1000-1200 a day to lose!

weighmoreweighless · 06/04/2026 13:42

THisbackwithavengeance · 06/04/2026 08:15

I don’t understand how so many on here are eating concentration camp level daily calories merely in order not to gain weight. Have we fucked up our metabolisms with constant dieting?

If the OP is gaining large amounts of weight on just 1600 daily calories, then something is wrong and I would be seeing my GP.

Me neither. My maintenance is as per the photo. The more a person weighs the more calories their body burns just to carry out basic functions. Unless they have something medically at play or their metabolism is buggered.

Weight gain after Mounjaro
SilenceInside · 06/04/2026 14:53

@weighmoreweighless there are various different formulae for working out TDEE and the one in the screenshot you've shown relies on knowing your body fat % to calculate, where most people would not know that accurately and so be using a different formula to calculate. You've also used Moderate exercise, where many people would only manage Light exercise or Sedentary if they work a full time desk job.

A woman who is shorter than you and not as active, using the formula where body fat % is not included, could easily come out with a TDEE in the 1400s, and find that it is accurate for her in terms of whether she maintains or loses weight.

weighmoreweighless · 06/04/2026 15:31

Taking off the body fat percentage gives me 200 calories less.

The BBC calculator gives me 1743 too so doesn’t take into about body fat percentage.

If people are sedentary then of course their tdee is going to be much lower. Disabilities aside, if people want to be able to eat more they need to be more active.

OddBoots · 06/04/2026 15:50

In terms of muscle gain, could you both be looking at slightly different measures? Gaining muscle in pure Kg terms and increasing muscle as a percentage of total body mass (because resistance exercise protects muscle and so more/all of the loss is fat) are both measures commonly used as they have value but mean different things.

RoseField1 · 06/04/2026 15:54

OddBoots · 06/04/2026 15:50

In terms of muscle gain, could you both be looking at slightly different measures? Gaining muscle in pure Kg terms and increasing muscle as a percentage of total body mass (because resistance exercise protects muscle and so more/all of the loss is fat) are both measures commonly used as they have value but mean different things.

Well the second one is body recomposition, not muscle gain. I hope the previous poster wasn't calling that muscle gain, because it isn't.

weighmoreweighless · 06/04/2026 16:50

I expect the issue is that becoming obese changes the metabolism and makes maintaining any weight loss long term very difficult.

Fishingboatbobbingnight · 06/04/2026 17:36

I do wish people would stop peddling this nonsense about ‘learning better food habits’ ‘reprogramming you brain regarding your attitude to food’ .. WLI do NOT play any part in neurological pathways or changing the way you think !!

it’s just yet another myth to beat you with when you inevitably fail !!

READ some proper peer reviewed studies so that you understand how these drugs work and then you will understand that it isn’t some magic fucking woo that turns off the ‘food noise’ . It’s a drug that affects you physiologically . IT DOES NOT RETRAIN YOUR BRAIN.

It affects the appetite centres in your brain making you feel fuller for longer.

It slows gut emptying . You feel fuller longer and satisfied after a small meal.

It controls blood sugar . (Particularly important if you are/have been obese as most people in this category are insulin resistant from years of yoyo dieting. ) This prevents the peaks and troughs of blood sugar which makes the overwhelming need to eat particularly hard to ignore.

Above all - the lack of that urgent need to fill your face - gives you the breathing space to make those health choices. If you are starving you will reach for the first thing you see Which is likely to be something processed or ready made. Which is normally not the best choice. If you are taking MJ you don’t feel this urgency and are much more likely to plan a nutritious small protein/fibre dense meal.

Given ALL the above. How can anyone truly believe that they can take these drugs to lose weight and NOT put it back on without it. You would need super human willpower ! Nothing to do with not having ‘failed to learn new habits’ .

If you take blood pressure medication to control your bp, you would not expect to control it through ‘will power’ if you stop taking it. WLI are no different. It’s illogical to assume otherwise.

Read the SUMMOUNT 4 trial papers. The actual evidence into how it works and maintaining that loss once a healthy weight is achieved. It’s pretty clear that the vast majority of those that stop the drug put a minimum of 75% of the loss back on within 2 years. With a low continuing dose being the only way to maintain the loss long term. There will of course be some phenomenal individuals with iron will power who can buck this statistic but as you can see from the trials these folk are pretty rare at 1:500. Which coincidentally is the same ratio for obese women who diet to healthy and maintain it for 5 years with diet and exercise alone.

The science is available to read on line. People need to read it and understand that they will almost certainly need to commit to the drug long term and view it as an investment in their health. As taking it , succeeding and stopping it will almost always be a literal waste of money in the long term.

I lost 9 st April 24-Jan 25 and maintain on 5mg since titrating down to 5 in May 26 and keep within 2kg +/- for a year . Never needed to get into Macros/TDEE or ridiculous amounts of exercise. I ride and Kayak a couple of times a week and do Tai Chi in the morning for 20 mins.

autumn1610 · 06/04/2026 17:42

Yeah I’m 4lbs off my starting weight. Took a few months and I hadn’t lost loads as came off it when prices went up. Massively regret coming off it without really being ready to

weighmoreweighless · 06/04/2026 18:05

I think this should be sold as a lifelong drug rather than saying it’s possible to stay on it for life. People are being misled thinking relatively short term use will solve their weight problem and leave them
slim as long as they maintain good habits. That’s obviously not the case. People are going to be very angry when they realise they are going to have to keep paying out. It might end up being on NHS prescription on time but for now it’s costing a lot of money and there’s stories of people getting into debt to pay for it.

JamesBoyle · 01/05/2026 10:31

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Wildgoat · 01/05/2026 16:06

weighmoreweighless · 06/04/2026 18:05

I think this should be sold as a lifelong drug rather than saying it’s possible to stay on it for life. People are being misled thinking relatively short term use will solve their weight problem and leave them
slim as long as they maintain good habits. That’s obviously not the case. People are going to be very angry when they realise they are going to have to keep paying out. It might end up being on NHS prescription on time but for now it’s costing a lot of money and there’s stories of people getting into debt to pay for it.

What a silly comment, 😂 you seriously believe the weight just comes on from fresh air. The body changes and gains weight from nothing? I’m agog !

of course if you maintain your habits you maintain the weight. If you over eat you gain.

if the op is gaining 4lbs a week on 1600 cals, she needs to be over eating by 2000 cals a day, she ain’t gaining it from water and fresh air.

back to school for yoh!

Truetoself · 01/05/2026 16:30

whilst for the vast majority of people it is straightforward calories in vs calories out I am convinced that there is another mechanism by which mounjaro works in ways other than appetite suppression. Unfortunately for you it sounds as though you need to reduce your calories further

Joannemercer63 · 13/05/2026 21:17

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Kitt1 · 14/05/2026 11:05

Gall10 · 05/04/2026 10:06

Eat less, move more =weight loss
esr more, move less=weight gain
its basic physiology….no magic involved, just will power.
Personally I know how hard this is to carry out.

🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️

Erm, you do realise that that’s complete rubbish for the majority of obese people taking WLI, don’t you?

The medication doesn’t just help you to eat less but it affects your body’s hormones and the way food is metabolised and therefore without it, even eating the exact same calorie diet won’t stop some people from putting the weight back on again.

That’s why a lot of people (me included) will need to stay on WLI or their replacements for life.

TaffyTabby · 14/05/2026 13:39

Everyone repeating the same old calorie in calorie out school of thought here. Chastising the OP like it’s their fault they haven’t managed to cure their obesity with willpower alone. It’s like expecting someone to will their hypertension away.

Cal in/Cal out m/TDEE rhetoric has been around for a looooong time. And yet obesity persists. It’s arguable whether it’s in fact completely false, or perhaps only part of the story, but I think the science clearly shows it doesn’t actually help anyone lose weight and keep it off. Hence the overwhelming data that calorie restriction diets do not work in the long term.

Listen to the Fat Science podcast. An actual physician. Yes people can damage their metabolism so much by dieting that they can gain weight even when eating “at a deficit”.

GLP drugs are much more complex than just appetite suppressants. They correct a whole cascade of metabolism hormones and signalling in the body.

OP. I agree that unfortunately you will probably need to take a GLP long term.

Gall10 · 15/05/2026 14:54

Kitt1 · 14/05/2026 11:05

🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️

Erm, you do realise that that’s complete rubbish for the majority of obese people taking WLI, don’t you?

The medication doesn’t just help you to eat less but it affects your body’s hormones and the way food is metabolised and therefore without it, even eating the exact same calorie diet won’t stop some people from putting the weight back on again.

That’s why a lot of people (me included) will need to stay on WLI or their replacements for life.

Nope….. eating less than your body needs results in weight loss…no exceptions whatever you may tell yourself.

Dailystreak · 14/06/2026 17:16

WellConfusedandDazed · 05/04/2026 09:24

3-4 pounds a week is a little scary, are you sure about your tracking? I had body scans when I was on MJ and when they told me I was losing muscle, I started lifting weights and worked up to very heavy weights 2-3 times a week. This has definitely helped me maintain. Muscle helps with insulin sensitivity and keeping your metabolism steady. What sort of exercise are you doing? If it’s heavy cardio it won’t help much and will spike your cortisol, which promotes fat storage.

Hi can I ask you if you started gaining weight when you started heavy lifting weights? I have been in MJ too and 2 weeks ago, I started strength training gently with light weights, kept the same calorie intake and drank 3 L of water and slept 8 hours a day. Since then I have gained 5 lbs. Normally I lose one and 1.5 lbs a week. So in total there will be 7lbs again. I stopped weightlifting 3 days ago and increase my water intake and still have not lost anything no whoosh affect’ nothing. I wonder what was your experience when you started weightlifting? And how did it affect weight loss?

PillowSwap · 14/06/2026 22:39

What @Peridot1 said may have some truth to it - that GLIs may also affect how some people process food and metabolise. So it may not be completely a case of “calories in, calories out“.

The OP’s lifestyle sounds very healthy, so it may be to do with that.

Also, OP, have you had a thyroid blood test?

I also agree with @TaffyTabby ’s broader analysis. I got 2 stone in a year and I don’t think my diet changed that much to be honest!

I am now a stable weight, still a little overweight. What I’m currently doing is just trying to reduce my Mounjaro dose to as little as possible (as I still get the side effects of fatigue and nausea), so at least it would be hopefully working “lightly” in the background. Maybe 5 mg dose, or even less.

Maybe OP could start taking WLI again and staying on but just at a much lower dose, which would be less expensive?

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