The LighterLife diet: What is it?
It's a very low calorie diet (VLCD) where, depending on how much you weigh, you consume between 570 and 1,200 calories a day. An average man needs about 2,500 calories a day and an average woman about 2,000 calories to stay the same weight. The NHS defines a VLCD as containing 1,000 calories a day or fewer.
In the LighterLife diet, meals are replaced with shakes, soups and bars and the diet is aimed at people who have one stone or more to lose. There are weekly counselling sessions in small, same-sex, groups to help you identify why you overeat and change your behaviour.
The amount of weight obese people following the diet lose and the speed with which they lose it, has made the diet controversial and means it frequently makes the news, not always for the reasons the company which runs LighterLife would hope for.
Actress, Pauline Quirke - best known as Sharon in the comedy Birds Of A Feather - endorsed LighterLife, losing three dress sizes in two months on the diet plan. On the LighterLife website she said: "I joined LighterLife in January 2011 and am already over a quarter of the way to my goal of 11 stone. I'm already three dress sizes lighter and it feels fantastic."
Jackie Llewelyn-Bowen, wife of TV interior designer Laurence Llewelyn-Bowen, is also reported to have used the LighterLife diet and shed five stone in five months.
The LighterLife Diet: What you can eat
It depends on how much you weigh. If you have a lot to lose and have a BMI of 30 or above you will follow the LighterLife Total diet where all your meals are replaced with nutritionally-balanced bars, shakes and soups and you have no conventional food whatsoever.
Before you can start this diet you'll need to see your GP.
The NHS recommends a VLCD should be undertaken for no more than 12 continuous weeks. After 12 weeks on LighterLife Total, you increase your calorie intake to more 1,000 calories a day for one week only, before returning to the diet.
Adding milk is one way to do this.
If you are following LighterLife Lite, which is for men or women with a BMI of 25-29.9 with one - three stone to lose, you have three meal replacements a day, plus one healthy, conventional meal from a list of everyday ingredients.
You can drink black tea or coffee on either diet and you're encouraged to drink up to two litres of water during the day or flavoured water with added fibre.
The LighterLife diet: How it works
You'll lose weight quickly because the amount of calories you consume will have been cut dramatically.
The speed of weight loss and the fact people feel reeducated about why they overeat are reasons why people keep to the diet.
Once you've reached your desired healthy weight there's a 12 week programme which slowly re-introduces food, starting with proteins and then progressing to vegetables and carbohydrates.