Mounjaro users discover key mistake stopping them from losing weight

A leading aesthetics practitioner has warned that failing to eat enough while taking the popular slimming jab Mounjaro could actually prevent users from losing weight.

Annabelle Welch, who treats patients on the drug at her clinic in Sevenoaks, Kent, said she regularly sees clients drastically cutting calories—unaware that this can cause weight loss to slow down or stop altogether.

Mounjaro, dubbed the ‘King Kong’ of slimming jabs, mimics appetite-suppressing GLP-1 hormones and can help users shed up to 20 per cent of their body weight in a year.

But without adequate nutrition, Welch explained, the body adapts by slowing its resting metabolic rate—the energy it uses to maintain basic functions like breathing and circulation—making it harder to continue losing weight.

In a video shared to TikTok via her page @juiceaestheticsuk, which has racked up more than 400,000 views, she outlined five key warning signs that patients may be undereating on Mounjaro.

These included hair loss, psychological issues, persistent muscle aches, feeling cold, and stalled weight loss.

Hair loss, she explained, occurs because hair growth isn’t considered an essential function. ‘If we’re not giving our body enough nutrition, what we do eat will be redirected to more vital functions,’ she said.

Mood swings, irritability and anxiety are also common signs. 

‘If you’re skipping meals, essentially you’re dropping your blood sugar levels,’ she explained—adding that this was leaving people with less energy and feeling more emotionally volatile.

Muscle aches that linger for days after a workout can be another clue. ‘You’re not fuelling your body with enough protein and nutrition after your exercise, so it’s not able to recover in a normal way,’ Welch said.

The body goes into ‘fight or flight mode’ because it doesn’t know when it’s next meal will be, she explained.

She added that while increased sensitivity to cold can be a normal side effect of weight loss, it may also point to undereating—especially if it’s accompanied by other symptoms.

‘It’s mainly if you’re feeling very cold in your hands and feet, or if it’s a warm day and everyone else seems hot but you’re not.’

Finally—and perhaps most surprisingly—stalled weight loss itself can be a sign, she said.

‘If you’re not fuelling your body with enough calories day to day,’ Welch said, ‘your metabolic rate will drop, and your body will begin conserving fat rather than burning it.’

Ms Welch’s video has attracted hundreds of comments from social media users, many of whom say they’ve experienced the symptoms she describes. 

One commenter, who admitted to eating just one meal a day, wrote: ‘I’ve been on it for six weeks and I’ve lost no weight.’

Another highlighted the catch-22 many patients face: ‘I’m struggling to eat — just living on boiled eggs, white fish and watermelon. Everything else makes me feel sick.’

Nausea is a common side effect of weight loss injections like Mounjaro, which can make it harder for users to eat enough — and unwittingly sabotage their own progress.

When one follower asked if eating more would cause regained weight, Welch replied: ‘Eat regularly, even if it’s small portions. Constantly fasting and skipping meals is going to lower your resting metabolic rate.’

Last month, GPs in the UK were allowed to prescribe weight-loss drugs for the first time in a bid to tackle the nation’s obesity crisis. An estimated 1.5 million people are now taking the jabs through the NHS or private clinics.

But some experts have raised concerns over potential risks. Recent data revealed that more than 100 deaths in Britain have been linked to slimming injections so far.

At least ten patients are confirmed to have died from pancreatitis—a life-threatening inflammation of the pancreas—after taking the jabs.

The Medicines and Healthcare products Regulatory Agency (MHRA) has since launched an investigation into whether people with certain genes may be more vulnerable to the condition.