It's hard not to envy celebrities. They have the lifestyles we desire. They also have the bodies.
Each has their method to look good and a celebrity endorsement can turn a diet plan into a worldwide phenomenon.
But are they slimming the healthy way?
We asked experts Mr Derrick Ong, dietitian and director of Eat Right Nutrition Consultancy, and Miss Sarah Sinaram, senior dietitian of Raffles Internal Medicine Centre at Raffles Hospital, to weigh in on three celebrity diet plans.
How the diet works:
In 2006, Beyoncé told Oprah Winfrey she lost 9kg on the Master Cleanse to prepare for the movie Dreamgirls.
Created in the 1940s by nutritionist Stanley Burroughs, the Master Cleanse involves consuming nothing but detox drinks, ideally six to nine glasses a week, for two weeks: a mixture of maple syrup, lemon juice, water, and cayenne pepper or ginger.
Both Miss Sinaram and Mr Ong agree that promoting a higher fluid intake is good in principle, but the Master Cleanse takes it to an unhealthy extreme as fluids completely replace food.
"An average adult should consume 1.5 to 2 litres of fluids daily.
"This diet more than fulfils that requirement," says Mr Ong.
But he cautions that someone on the Master Cleanse risks deficiencies in protein, fat, iron, calcium and in Vitamins A, D, E and K (fat soluble vitamins).
Miss Sinaram warns: "The Master Cleanse almost seems like a starvation diet."
How the diet works:
In January, Posh Spice enthused on Twitter about a "healthy eating cook book" titled Honestly Healthy
This advocates a diet that is 70 per cent alkaline foods and 30 per cent acidic. "Our bodies function best when in an overall alkaline state," states the book's official website.
The website claims that apart from natural weight loss, the benefits of the alkaline lifestyle include improved digestion and immunity. The diet is high in fruit, vegetables and whole grains, and also includes nuts, coldwater fish as well as olive and linseed oils.
Alkaline dieters are meant to avoid dairy and meat, and have to cut out sugar, fizzy soft drinks and caffeine.
While the diet's high fibre is good, it neglects proteins, vitamins and minerals, says Miss Sinaram.
Mr Ong adds: "Although this is an extremely popular diet and sounds convincing, its scientific basis is sadly lacking." The acid-alkali balance of our bodies is controlled by sophisticated chemical buffer systems in our cells and is not easily influenced by what you eat.
How the diet works:
In March, Paltrow sparked controversy after she reportedly made her children avoid foods like pasta, bread and processed grains.
In her cookbook she wrote: "Sometimes when my family is not eating pasta, bread or processed grains like white rice, we're left with that specific hunger that comes with avoiding carbs."
Paltrow's cookbook also advocates avoiding gluten: "Every single nutritionist, doctor and health-conscious person I have ever come across... seems to concur that (gluten) is tough on the system..."
"Carbohydrates are our body's preferred fuel to support physical and mental activities," says Miss Sinaram.
"Cutting out or significantly reducing carbs in one's diet basically means a reduction in caloric intake. It's no wonder that Paltrow and her family experience hunger on such a diet."
On the other hand, Mr Ong notes that Paltrow's diet has its positive points:
"It sounds like Paltrow is advocating a diet which limits refined grain and sugar products. There's nothing new about this, and there is some evidence to show that limiting these can lead to healthy weight loss and other good health outcomes."
Miss Sinaram and Mr Ong also agree that gluten isn't as bad as Paltrow makes it out to be.
"The statement that gluten is 'tough on the system' is a questionable one," says Mr Ong. "Avoiding gluten is not necessary unless one has coeliac disease (a digestive condition where the sufferer's stomach lining has a reaction to gluten)."
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