The alkaline diet boasts quite the fan base. Fashion designer Victoria Beckham, ex-Take That star Robbie Williams and model and TV personality Lisa Snowdon have all tried, tested and loved it.
Melanie C has declared the Honestly Healthy cookbook left her feeling "amazing!", Kelly Brook keeps a copy of it in her kitchen and Made In Chelsea's Millie Mackintosh has also followed the recipes.
HELLO! Online have spoken to Natasha Corrett, Sienna Miller's step-sister and the gourmet chef behind the bestselling Honestly Healthy cookbook, to find out what all the fuss is about.
First off, Natasha, who lost two-and-a-half stone over two years and wrote the cookbook with her godmother, nutritionist Vicki Edgson, explains that this is not an alkaline diet. It's an alkaline lifestyle.
"If there was one diet in the world that worked, there would only be one diet," she tells HELLO! Online. "What I hate about the words 'diet' and 'detox' is that they're a quick fix and something that people hate."
What Natasha and Vicki set out to do with their number one bestselling cookbook is get the concept of diet out of people's minds and show that "it can just be a way of life", and that "if they had a healthy lifestyle they wouldn't have to diet again".
So, what’s the alkaline lifestyle all about? "Bringing your body back to an alkaline level because we function best when slightly alkaline, which is the same pH as our blood.
"So cutting out very acid-forming foods, such as meat, sugar, alcohol, caffeine, wheat, cow’s dairy."
Weight loss is an obvious benefit to the eating regime. But other perks include improved skin, more energy, no bloating and "feeling at your optimum health all the time".
Natasha herself went from being incredibly bloated, having bad skin, low energy and polycystic ovaries, to losing more than two stone, and feeling healthier all round – including no longer suffering from polycystic ovaries.
Don't be confused by what is acidic and what is alkaline, once digested. Lemon and lime are surprisingly alkaline when broken down by the body, while cow's milk is actually acidic.
The best bit of this lifestyle is that you can eat what you want – as long as you stick to the 70-30 rule. Natasha says: "Thirty per cent of the time you let your hair down and eat what you like and 70 per cent you follow this because it will make you feel fantastic."
Over the course of a week, thirty per cent translates to three or four meals, or maybe a glass of wine – "it could be an ice-cream or a glass of wine or a pizza or meat."
Curious? Try a day in the alkaline lifestyle with these breakfast, lunch, dinner and dessert recipes from Honestly Healthy.
Honestly Healthy Eat With Your Body In Mind by Natasha Corrett & Vicki Edgson, published by Jacqui Small £20.
Report by Miriam Foley