HER role as the hectoring host of You Are What You Eat has led her to being loved and loathed in almost equal measure by millions of TV viewers.
Now Gillian McKeith has stirred up more controversy by lending her name to a contentious weight loss formula.
The Perth-born health guru insists her Slimmers Formula can help people "lose inches of fat" while they sleep.
But nutritionists and c
onsumer groups have questioned its effectiveness and claimed her product is not supported by solid scientific evidence.
Gillian McKeith Cellfood Slimmers Formula, which costs £29.99 for a 118ml bottle, is being sold from her website and over-the-counter at health stores across the UK.
The TV personality hails her liquid food supplement as an ideal and simple way to lose weight literally overnight.
Promotional material states: "Slimmers Formula combines natural ingredients that decrease fat storage and increase the body's metabolic rate to burn more calories.
"It can help you lose inches from areas of your body with the most excess fat. Best of all it works naturally while you sleep and it couldn't be easier to use: just add the Formula to a glass of water at bedtime and go to sleep."
Slimmers are urged to stop eating "three hours prior" to using the product and to combine it with a "healthy diet and regular exercise".
But NHS nutrition expert Lucy Jones said people should think twice before buying the supplement.
The spokeswoman for the British Dietetic Association said: "There is no magic pill, powder, potion, formula, supplement or anything else that is going to make you magically lose weight overnight and keep it off. If anything does make you lose weight overnight it is going to be a diuretic or laxative, which will make you go to the toilet, but the results will only last until you eat or drink again.
"Because Gillian McKeith is such a high-profile figure people are going to feel there is a level of trust they can take from that.
"But unfortunately the hard scientific evidence just isn't there to back it up."
Jones said the rules which came with McKeith's product were most likely to account for any slimming success.
"If you are stopping someone from eating in the evening, they may well lose weight, but it will be nothing to do with this formula."
Medical Research Council nutritionist Holly Margerison was equally sceptical about the product's claims. The scientist, who is based at Cambridge's Centre for Human Nutrition Research, put the Formula's two main ingredients under the microscope.
She said: "L-Carnitine is an amino acid derivative that has been marketed as a slimming supplement but there is no scientific evidence to show that it improves weight loss.
"Garcina Cambogia, or hydroxycitric acid, is claimed to help regulate appetite, stop cravings for sweet food and stimulate the metabolism.
"There is a small amount of animal research to support these claims, but the human trials have yet to yield any significant results and make the use of this extract in slimming supplements questionable."
A spokeswoman for Which?, the independent consumer organisation that has investigated products with similar ingredients, said: "We advise against using any over-the-counter weight-loss supplements.
"Our experts question their effectiveness, they can be expensive and can also have side effects."
McKeith has also launched a branded Cellfood Multivitamin Spray, which people are urged to use directly under their tongue six times a day.
She claims it contains "12 essential vitamins" and states: "The spray completely ensures that you get the full possible benefit from these important nutrients."
The Food Standards Agency Scotland said that most people should be able to get all the nutrients they need by eating a varied and balanced diet.
A spokeswoman said: "If you choose to take supplements it's important to know that taking them for too long can cause harmful effects".
A spokesman for McKeith Research, which markets products endorsed by the TV personality, said: "We stand by the efficacy of the product, and because of this, we offer a full refund guarantee if a consumer isn't satisfied."
The Scottish broadcaster, author and entrepreneur is no stranger to controversy.
In 2007 McKeith agreed to cease using the academic title "Dr" in advertisements after the British Advertising Standards Authority (ASA) ruled it was "likely to mislead the public".
The Edinburgh University linguistics graduate obtained a master's degree and a PhD, both in holistic nutrition, via a distance-learning programme from the non-accredited American Holistic College of Nutrition.
In 2006 McKeith was censured by the Government Medicines and Healthcare products Regulatory Agency (MHRA) for selling unproven herbal sex aids.
The products Fast Formula Wild Pink Yam Complex and Fast Formula Horny Goat Weed Complex were subsequently removed from sale.
McKeith's TV shows You Are What You Eat and Supersize Vs Superskinny have attracted large ratings and her spin-off books have become best-sellers.
In her most popular show, the Scot berates overweight individuals, including Pop Idol singer Michelle McManus, into altering their eating habits, and sifts through their excrement for apparent signs of ill health.
The product rangeCellfood Concentrate
McKeith Research promotes the product as a proprietary formulation of naturally sourced ingredients with a wide range of trace minerals and nutrients, including "dissolved oxygen", in a water base that gives the cells and the body what it needs to maintain health and wellbeing.
Cellfood Slimmers Formula
The Formula is a liquid food supplement that the manufacturers insist can help to support weight loss plans in a safe and effective way. Its key ingredients are L-Carnitine, which they claim helps break down the fat, and Garcinia Cambogia billed as a natural appetite suppressant. They state that by burning more calories, it allows the body to lose weight in a natural way.
Cellfood Multivitamin Spray
It is claimed that six daily sprays in the mouth will provide 12 important vitamins people need to stay healthy: vitamin A, vitamin D, vitamin E, vitamin C, vitamin B1, vitamin B2, vitamin B3, vitamin B6, folic acid, biotin, vitamin B12, vitamin B5.
24 Hour Detox Plan
This supplement contains a range of "star superfruits" including papaya, pineapple, pumpkins seeds and lemon balm.
The manufacturers claim that papaya, in particular, has powerful anti-oxidant effects, needed to prevent damage from the release of toxins. They also hold that pumpkin seeds increase antioxidant capacity and reduce lipid peroxidation.
In addition they claim that lemon balm can have a liver supporting effect and increase levels of beneficial glutathione. The product also contains shitake mushrooms and magnesium.
The full article contains 1105 words and appears in Scotland On Sunday newspaper.
