FROM Dukan and “teatoxes”, to 5:2 and Keto, keeping up with diet trends can be tricky. One of the hottest diets right now – the Cambridge Diet (or Cambridge Weight Plan) – claims it can help shed weight fast , thanks to its extremely low calorie limit.

But is it safe and will the weight stay off long-term?

What is the Cambridge Diet?

This weight-loss plan advocates regular consumption of meal replacement shakes, soups, porridges and snack bars, designed to fulfil all of your daily nutritional requirements, while cutting out hundreds of calories.

It claims to help dieters lose up to a stone a month, without depriving them of nutrients.

How does it work?

There are six variations of the plan, ranging from 440 to 1,500 calories a day, depending on factors such as goals. Step one asks dieters to cut out all “normal” foods, eat only Cambridge Weight Plan products and drink 2.5-litres of water.

Later stages are more flexible. as you slowly introduce solid foods as you shed weight. The idea is you eat so few calories your body is forced into ketosis, burning fat stores rather than glucose.

The weight tends to fall off Cambridge dieters rapidly – but experts warn it should not be followed for more than 12 continuous weeks.

The plan comes with guidance and supervision This diet is not to be entered into without supervision, and some steps might even require written consent from your doctor.

You can only get your hands on the products, which typically cost around £2.40 per meal, by meeting with a Cambridge Weight Plan consultant, who will design a programme which fits your needs and track progress.

What is a typical day’s food?

At stage one, the diet could be a strawberry shake for breakfast, a banana shake for lunch, and chicken and mushroom flavoured soup for dinner. Step three mixes the Cambridge Weight Plan meal replacement products with a 150kcal breakfast, a salad lunch of green leaves, a 400kcal dinner, plus 200ml skimmed milk and at least four pints of fluids.

Is it safe?

Under one-to-one supervision from a trained consultant, the Cambridge Diet claims to be safe and healthy, but some experts do not recommend diets restricted to under 600 calories per day.

Max Bridger, a personal trainer from LDN Muscle (ldnmuscle.com), says: “It’s not something I’d recommend. Don’t expect to keep the weight off when you return to normal eating. As well as being tough to achieve, ketosis is easy to lose, and comes with side effects like bad breath and nausea.”

Before making any extreme changes to your diet, speak to your GP.