A diet shake up and exercise is usually the go-to approach for those seeking to shift the scales.
But while this usually means cutting out the junk food and packing in the fruit, veg and whole grains, others prefer a more extreme option — soups and shakes.
In a matter of weeks, such potions and plans promise to help you drop dress sizes.
While such schemes have long drew criticism from experts for being unsustainable, one approach offered on the NHS was this week hailed as ‘life-changing’.
Research revealed the 800-calorie a day soup and shake plan can even reverse type 2 diabetes by helping patients lose 19.6lbs (8.9kg), on average.
While that specific diet — the Cambridge Weight Plan, which one person described as ‘horrendous’ — is offered only through consultants, there are dozens of other of meal replacement options available on the market that promise similar results.
Here, MailOnline has rounded up some of the most popular.
Kieran Ball, 47, who took part in the pioneering NHS-backed trial, said that while the first seven weeks were ‘horrendous’, the results were life-changing — reversing his type 2 diabetes.
Dr Duane Mellor, a registered dietitian at Birmingham’s Aston University, said such meal replacement plans make it possible to restrict calories.
This is more challenging to do and maintain with normal food and could result in a vitamin or mineral deficiency, he said.
But meal replacements shakes and soups are usually fortified, so should meet any nutritional needs, he said.
‘This is also the reason why you cannot use any milkshake or soup if you are trying to lose weight to try and put your type 2 diabetes into remission,’ Dr Mellor noted.
He said: ‘[Meal replacement diets] can be very effective, as can other diets including low carbohydrate approaches.
‘The advantage of this approach is it can give people a break from having to choose foods and hopefully gives them success in losing weight.’
However, he noted that this approach can have problems, as when returning to eat normal food again, it can be challenging to make healthy choices and maintain weight loss.
And Professor Tim Spector, a top nutritionist, told MailOnline that the extreme diet can help ‘a very small number of highly motivated individuals’ to reverse their diabetes.
However, it is ‘completely the wrong message’ to give people who are desperately trying to slim down that they can use ultra-processed substitutes to do so, said the author of Sunday Times best-sellers Food for Life and Spoon Fed.
Other experts, such as NHS medic Dr Aishah Iqbal, has warned that the approach is often unsustainable and users commonly see the pounds pile back on once the diet has ended.
The NHS said very low calories diets, that involve eating 800 calories per day or fewer, should only be followed under medical supervision and for a maximum of 12 weeks.
Optifast
Typical meal plan: Two meals a day are replaced with Optifast shakes or soups. One Optifast snack bar is allowed. One meal of 200 to 250 calories made with healthy ingredients should be eaten.
Calories per day: 800 to 1,000
Cost per day: £7.10
Optifast is a rigorous six-week diet plan that requires you to swap out conventional foods for meal replacement products.
These include vanilla, strawberry or chocolate shakes and tomato, vegetable and potato and leak soup.
The number of meals replaced by the products in a day depends on your body mass index (BMI). The higher it is, the more food you replace.
The first three weeks are challenging. Your daily intake is severely restricted to around 800 calories per day.
This is less than half the calories a woman needs to consume per day to maintain her weight and less than a third of what a man requires.
Two of your main meals are replaced by a flavoured shake or soup, while an Optifast snack, such as a cereal bar is allowed alongside a 200 to 250 calorie meal.
Because of the militant and exhaustive regiment, you are advised to avoid strenuous physical activity for these three weeks.
After the first three intense weeks, the plan eases and you are allowed to reintroduce regular meals in place of Optifast products.
But, you still do not get free reign over your food choices. You still have to keep your calorie intake under 1,200.
You are also allowed to introduce light exercise as part of your routine.
The Nestle company advises replacing one meal a day and up your calories to 1,500 to maintain the weight loss.
Slenderplan
Typical meal plan: Two meals a day are replaced with Slenderplan shakes, soups or bars. One cooked meal a day is allowed. It should be just 600 calories for women and 800 calories for men. Three snacks are also allowed each day of up to 300 calories combined.
Calories per day: 1,200- 1,350
Cost per day: £4.75 excluding the one cooked meal
Slenderplan provides a more relaxed approach, more suited to those with less restraint and who love a midnight snack.
Following a seven-day meal plan, dieters can consume around 1,250 calories per day.
The approach from Slenderplan, which is part of Superdrug, involves replacing two meals a day with shakes, such as strawberry swirl and caramel cream, or soups, such as creamy tomato and creamy chicken.
Those following the plan make one meal a day themselves. But it should be just 600 calories for women and 800 calories for men.
Slenderplan provides recipes for these, such as spaghetti bolognese and salmon with roasted vegetables.
The plan also allows three snacks each day of up to 300 calories, such as blueberries, a banana or Slenderplan snack bars, which come in caramel, peanut and chocolate flavours.
The plan won’t break the bank either, as their meal replacement shakes costs, on average, around £5 for 10.
Slenderplan also suggests that their consumers should exercise regularly and drink two litres of water every day.
SlimFast
Typical meal plan: Breakfast and lunch are replaced with SlimFast shakes or bars. A conventional cooked meal for dinner is allowed. It should be just 600 calories for women and 800 calories for men. Three snacks are also allowed each day of up to 300 calories combined.
Calories per day: 1,300
Cost per day: £3.25 excluding dinner
Eating six times a day while on a diet isn’t the most common tactic used to lose weight. But SlimFast has formulated a routine for those who love to eat little and often.
With a simple daily routine combining conventional foods and diet products, the company promises results through a variety of different programmes.
The more favourited routine is their classic five snacks and one meal approach.
For breakfast, dieters are allowed one shake, which come in flavours such as strawberry, chocolate and banana and contain around 200 calories.
This is followed by one meal bar, which include chocolate chip, chocolate caramel and rocky road, or shake for their lunch.
The plan then recommends a normal meal for dinner, which is under 600 calories for women and fewer than 800 for men.
It then allows for three snacks throughout the day, each of which are under 100 calories. These include a pot of Greek yogurt, blueberries or a banana.
This averages your daily intake to an unforgiving 1,300 calories.
For those who struggle with their energy levels, SlimFast also offers a keto version of their programme.
Advocates say keto diets encourage ketosis, which is a metabolic state that occurs when your body burns fat for energy instead of glucose.
Huel
Typical meal plan: For breakfast and lunch Huel suggests having one of their shakes. A conventional cooked meal for dinner is allowed but they suggest keeping this under 700 calories. Two snacks, one in the afternoon and one in the evening, are recommended.
Calories per day: 1,500
Cost per day: £3.68
Rather than drastically changing your routine from day one, Huel, which has been labelled ‘food of the future’, adopts a more relaxed and diluted start.
They advise newcomers to start replacing one meal a day to begin with and after three to five days, slowly replace more with its products.
While Huel can help people lose drastic amounts of weight, they do not label themselves as a diet product.
However, they advise their customers on how they can lose with through articles on its website, explaining that to lose 1lb per week, they would need to consume a calorie deficit of 500 calories.
It also sets out a diet plan to do this, which includes having two scoops of its powder for breakfast and lunch and a Huel bar as an afternoon snack.
The powder, which comes in cinnamon swirl, berry and mint chocolate flavours should be mixed with 500ml before being consumed.
Huel then recommends an evening meal of around 700 calories and an evening snack of 210 calories.
They do offer advice on how to lose more drastic amounts of weight but explicitly warn their customers that consuming a deficit of 1,000kcal per day is ‘very tough’ and that they do not recommend it.
Shake That Weight
Typical meal plan: The diet plan consists of a Shake That Weight shake for breakfast, soup for lunch, one snack and a shake for dinner.
Calories per day: 800
Cost per day: £6.54
On the more extreme and vigorous side of dieting, Shake That Weight offers an eight week solution to those with a BMI over 25, which is considered to be overweight.
Their 800 calorie daily limit is not for the faint-hearted and the company advises consulting your GP before following the plan.
Their plan, which is most suitable for those with pre-diabetes or type 2 diabetes, consist of three meal replacements and a snack.
A typical day on the unforgiving diet plan consists of a 208 calorie shake for breakfast, a 200 calorie soup for lunch, a 200 calorie snack and a 205 calorie shake for dinner.
Flavours include chocolate, strawberry and banana.
Due to the extreme conditions it is recommended that this should only be followed for a maximum of three weeks or eight if you have GP approval.
Shake That Weight warn their customers that headaches, nausea, lethargy, constipation and menstrual irregularities could be a side effect.