Despite the ubiquity of the weight-loss jabs, the appetite (sorry) for losing weight the old-fashioned way, via diet and exercise, remains strong.

In fact, if you’re on the jabs, you could also learn a lot from a retreat: while Mounjaro et al will undoubtedly help you eat less, no medication can teach you how to build muscle, strengthen bones and learn the rule book for long-term health and balance.

There’s a weight loss retreat for everyone, whether you want to shed pounds with the help of high-tech wizardry, or keep matters natural and old school. You can go totally hardcore – or make a holiday out of things, with a side order of slimming down. Mayr cure or Ayurveda? Austria, India, Thailand or… Dorset?

I’ve been reviewing retreats for 35 years (plus I always seem to need to lose some pounds) so I know my colonics from my cryotherapy.

I have also learned (the hard way) which retreats to avoid like the plague – let’s not talk about the one where I passed out, the one where I ended up with palpitations – or the one where I concussed myself with a kettlebell.

So where do I go when I need to drop a dress size? These, trust me, are the very best I’ve found.

1. The Body Retreat, Dorset: The down-to-earth, fun one

Country walks, yoga, Pilates, short and sharp workouts keep you busy at The Body Retreat in Dorset

This is the weight-loss retreat I recommend again and again, because you don’t only shed pounds while you’re there, you’re given practical tools to keep it off when you get home.

We’re talking DIY workouts that don’t require fancy kit, and healthy food you can whip up in your own kitchen. Meals, movement, mindset – everything has long-term goals in mind.

It’s a group retreat, supportive and fun – more like a friendly house party (it’s women-only – sorry, chaps).

Country walks, yoga, Pilates, short and sharp workouts (suitable for absolutely anyone – even if you need to do it from a chair), talks, workshops and fabulous treatments keep you busy.

I’ve lost track of how often I’ve been (think it’s seven times now), often just because I want to have a reset, move my body more and have a good laugh with a lovely bunch of people.

They have a bolt-on for guests on GLP-1s, so it’s a great choice if you’re jabbing or pill-popping and want some extra, knowledgeable support.

Jane Alexander, who has reviewed weight-loss retreats around the world for 35 years, has revealed her go-to locations to drop a dress size while on holiday

You’re given practical tools to keep the pounds off when you get home with healthy food you can whip up in your own kitchen

What will you eat? Food is all home-cooked and designed to show you it’s perfectly possible to continue the regime at home.

Breakfast could be yogurt with berries, poached eggs, satisfying smoothies, homemade granola.

Lunch and dinner embrace hearty soups with homemade crackers; frittata; grilled salmon or chicken (vegetarian and vegan options are always available).

There’s a protein snack to keep blood sugar balanced – apple slices with nut butter or a smoothie.

You drink herbal tea and are encouraged to sip plenty of water.

How much will you lose? I once lost a thumping ten pounds (4.5kg) in just five days. The average weight loss is 1-2.5kg per week.

How to do it? From £1,875 for five days. thebodyretreat.co.uk

2. Dharana Retreat, India: The pleasant panchakarma one

The decor at Dharana Retreat is Zen luxe, and it is recommended to try and nab a villa with its own pool if you can

Panchakarma is ayurveda’s 5,000-year-old deep detox programme. It didn’t start out as a weight-loss strategy but everyone (including Gwyneth Paltrow and Katy Perry) does it because you inevitably drop several sizes.

Panchakarma can be pretty hardcore: expect to drink plenty of ghee (clarified butter) and get ready for unpredictable bowel movements (honestly this is one weight-loss retreat where sharing a room is not a great idea, no matter how close the relationship).

Equally pick your venue with care. I’ve done panchakarma all over the world but would always choose Dharana, a three-hour drive from Mumbai (you’re picked up at the airport).

The decor is Zen luxe (nab a villa with its own pool if you can) and you can summon a buggy by WhatsApp so you’re never caught short (the fear is real).

Packing is simple – flesh coloured underwear, comfy sandals, sunnies and a hat are all you need as you will live in the kurta pyjama set of loose trousers and tops, all provided and freshly laundered each day.

A three-hour drive from Mumbai, the Indian retreat offers pristine yoga in lush surroundings

Dr Sharji who heads the programme is scientifically focused but warm and kind. Treatments (very oily) are delicious (not always the case with panchakarma); the yoga is pristine and the surroundings are lush.

Purging in paradise, for sure. Can’t face the ghee? They also offer less stringent detox and weight-loss programmes.

What will you eat? On a full panchakarma programme you eat kitchari (mung dhal and rice), steamed vegetables, clear vegetable soups, herbal teas and infusions. It’s bland (put all thoughts of standard Indian curries out of mind), but it’s comforting and satisfying: you truly don’t feel hungry.

How much will you lose? 2-5kg in first week; 1-2kg per week after that.

How to do it? From £2,159 for five nights. dharanaretreat.com

3. Park Igls, Austria: The mountainous Mayr one

Set above Innsbruck, Park Igls is smart but not show-offy and attracts an older, fiercely loyal clientele

Mayr medicine, founded by Austrian doctor FX Mayr, has espoused the importance of balancing the biome for weight loss and health for over 100 years.

It’s wildly popular amongst celebs such as Rebel Wilson, Naomi Campbell and Elizabeth Hurley, so glitzy clinics such as Lanserhof, Mayrlife and VivaMayr (while excellent) can feel like influencer-central.

I prefer low-key Park Igls, set above Innsbruck, which attracts an older, fiercely loyal clientele. It’s smart but not show-offy, and packs a pound-bashing punch.

Back in the day you’d be told off for talking during meals, and staff would patrol the dining room checking you’d chewed each mouthful for the designated 40 times.

It’s not quite so strict now but, if you like a warm, buzzy atmosphere, this isn’t the place for you.

When you’re not chewing, there’s a fabulous gym with 360-degree views of the mountains, and a roster of top-notch physios and PTs who will coax even the most recalcitrant bodies into movement.

March around the ice-cold pool at the Kneipp station and feel like you have taken a step back in time to the days of the original naturopathic spas

Igls also has extraordinarily good massage therapists – the little known Marnitz and Terrier approaches are worth a go, if you like your bodywork hardcore, verging on masochistic.

The pool and sauna area are great; and the Kneipp station (where you march around the ice-cold pool) feels like a step back in time to the days of the original naturopathic spas.

What will you eat? Monotony rules here. Most people settle for one breakfast for the duration (I went for scrambled egg on gluten-free bread, and malt coffee with milk).

Lunch and dinner feel like snacking at a deli, tiny portions of ham, trout, cheese, veggie spreads, divine soup (and I’m not really a soup fan) and, of course, the infamous dry bread (to teach you the power of chewing properly).

How much will you lose? Around 2-4kg in a week.

How to do it? From £3,149 for seven nights. park-igls.at

4. Buchinger Wilhelmi, Germany: The hardcore fasting one

Buchinger Wilhelmi sits on Lake Constance, where they take weight loss exceedingly serious and you will consume a minuscule 250 calories a day

The German clinic, on Lake Constance, is world-renowned for its medically supervised fasting protocols. They take weight loss exceedingly seriously here – it’s not the place to come if you want a softly-softly approach.

You consume a minuscule 250 calories a day, just enough to support the liver and prevent crashing headaches.

Each visit starts with a comprehensive diagnostic check-up and you will see a doctor at regular intervals, and check in with a nurse every morning.

You dump the weight swiftly here; inflammation calms down and muddy minds clear like magic. It’s the ultimate clear out.

People bond over deprivation (though the hunger vanishes after the first couple of days, a side effect of your body going into ketosis).

Many conversations struck up on the daily hikes develop into deep friendships – people return at the same time each year and book their favourite therapists a year in advance.

There’s no shortage of activities with a varied programme of talks, workshops, classes and concerts, as well as aqua aerobics and gym-based circuits

There’s plenty to do with a varied programme of talks, workshops, classes and concerts. I loved morning yoga and meditation; others preferred aqua aerobics and gym-based circuits.

The outdoor pool is delicious and there’s even an art studio where you’re encouraged to splash paint around.

Old ailments vanish or ease and most people find that as well as losing pounds, they gain mental clarity and better sleep. Some even swear it soothes the soul; not so crazy when you consider fasting has been a spiritual practice for millennia. Amen to that.

What will you eat? Let’s be honest, not a lot. During the fasting phase it’s two bowls of thin vegetable broth (nothing to chew) a day – one at lunchtime, one in the evening. If you baulk at the broth, there’s a vegetable juice option served at lunch.

Either side of the fast, food is surprisingly stolid (baked potato stuffed with veg; a plateful of white asparagus, stewed apple, whole grains and rice with vegetables) – but still vegetarian.

How much will you lose? It’s possible to lose 3-6kg over seven days.

How to do it? From £2,099 for seven nights. buchinger-wilhelmi.com

5. Mount Med, Austria: The micro-managed longevity one

Mount Med feels more like a luxury boutique hotel than a clinic with its supremely comfortable, alpine setting

Can you lose significant weight on five solid meals a day? Absolutely. I shed half a stone in under a week here without even a whiff of deprivation.

The clinically proven programme was originally designed by Dr Alexander Papp, to improve postoperative recovery for his cancer patients, but he soon realised its benefits were more far-reaching – people not only lost weight; they turned back the clock on biological ageing.

It combines the benefits of intermittent fasting, calorie restriction and a modified ketogenic diet – low-fat with normal amounts of protein.

‘It keeps you full, stabilises blood sugar levels and promotes fat loss,’ says Dr Papp. It’s minutely tailored to each guest (you have a battery of tests before you start, including a scan that maps your body in horrifying 3D – the ultimate incentive).

Every tiniest thing that could block fat loss (from hormone or metabolic issues to dietary deficiencies to fitness fails) is scrutinised.

The Austrian retreat features immense gym and plenty of high-tech biohacking gizmos and machines

There’s an immense gym and plenty of high-tech biohacking gizmos and machines. Mount Med is supremely comfortable – it’s more like a luxury boutique hotel than a clinic, and the alpine setting is divine.

What will you eat? Lots – and it’s divine. Bento boxes of smoked salmon, salad, eggs, crackers are served at breakfast, followed by an omelette. Mid-morning you help yourself to a protein shake.

Lunch is broth, a help-yourself salad and a main course of fish, meat or a vegetarian option. Mid-afternoon is a protein cookie or two.

Dinner is a starter (grilled octopus, crab salad, tiny rolls of chicken), broth and salad (as for lunch) and a main course of protein with sublime sauces and vegetable accompaniments – say, salmon on vegetable risotto; braised veal cheeks on cauliflower cream; entrecote steak with jus and vegetable strips. It’s hard to believe you’ll lose weight on that amount of food but amazingly you do.

How much will you lose? The average weight loss is 1.5-3.5kg per week.

How to do it? From £3,369 for five nights. mountmedresort.com

And the ones I still want to try...

SHA, Spain and Mexico: The celebrity MOT one

A-listers such as Tom Cruise and Kylie Minogue visit SHA for the ultimate fix-me destination

SHA is the ultimate fix-me destination, beloved of celebs like Tom Cruise, Mick Jagger, Lily James and Kylie Minogue.

High-tech diagnostics, world-class doctors and trainers, minimalist chic accommodation. Fat doesn’t stand a chance.

How to do it: From £5,579 for seven nights. shawellness.com

Layan Life at Anantara, Thailand: the med-luxe reboot one

Layan Life in Thailand can help you lose some pounds without sacrificing the trappings of a pampering luxury beach holiday

Thailand’s big hitter spas (Chiva-Som, RAKxa, Kamalaya et al) hit that sweet spot between traditional Thai medicine (arguably the best bodywork in the world), precision diagnostics and high-tech therapies. I fancy Layan Life which promises to shed pounds without sacrificing the trappings of a pampering luxury beach holiday.

How to do it: From £4,360 for five nights. layanlifephuket.com

Zulal Wellness Resort, Qatar: The blissed-out spa one

The desert-meets-sea retreat in Qatar can support those whose weight issues have a stress element with targeted therapies to help soothe burned out nervous systems

This gorgeous desert-meets-sea retreat draws on the wisdom of traditional Arabic medicine which takes a holistic view of health (if your weight issues have a stress element, targeted therapies help soothe burned out nervous systems).

Another perk? If you want to take your family along for the ride, Zulal has you covered.

How to do it: From £1,669 for five nights. zulal.com

Healing Holidays (healingholidays.com) can organise trips to many of the retreats mentioned here (in addition to other weight-loss programmes).