What is it?
LighterLife has a number of diet plans including a very low calorie diet (VLCD) where, depending on how much you weigh, you consume between 600 and 1,200 calories a day. An average man needs about 2,500 calories a day and an average woman about 2,000 calories a day. The NHS defines a VLCD as containing 1,000 or fewer calories a day.
In the LighterLife VLCD meals are replaced with shakes, soups and bars and the diet is aimed at people who have 3 stone (19 kg) or more to lose.
There are weekly counselling sessions in small, same-sex groups to help you identify why you overeat and to help 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 back in 2011, losing three dress sizes in 2 months on the diet plan. However, not all the weight has stayed off.
But, according to the LighterLife website, Loose Women star, Denise Welch lost 2 stone on the diet and has maintained the weight loss for over 3 years.
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 Totally Different or Total plan 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 1 - 3 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.
LighterLife also has a fasting diet and a management plan for when you've reached your ideal weight.