After Adele made headlines last year for her sudden weight loss , rumours linked the British pop star to a diet trend called “sirtfoods” , rich in dark chocolate, red wine and green juice. But recently Adele said in a Vogue interview that she hasn’t followed any particular diet, and “inside sources” claiming to have spoken to her were unreliable. How does Adele spend her US$190 million fortune? British Vogue 🇬🇧 https://t.co/UgGgfbF6lZ pic.twitter.com/V3p8UcZ7mk — Adele (@Adele) October 7, 2021 “All these other people have come out saying that they trained me,” she told Vogue . She called them “weirdos”, adding, “I’ve never met them in my life!” But her rumoured attachment to the diet still prompted immense interest, spiking sirtfoods to trend online each time Adele made waves on social media. Inside Meghan Markle and Prince Harry’s ‘Palace of Secrets’, The Carlyle View this post on Instagram A post shared by AdeleInPoland Fanpage 💋 (@adeleinpoland) The concept was popularised in 2016 in a book titled The Sirtfood Diet by the pharmacist Aidan Goggins and the nutritionist Glen Matten. It involves eating foods that activate a protein called sirtuin, hence the name, and cutting calories for weight loss. But, while the foods included in the diet are healthy, it could have some drawbacks by restricting what and how much you can eat, potentially making it tricky to follow in the long term. Are sirtfoods good for you? Blueberries, strawberries, red wine and dark chocolate are just a few examples of the most appealing sirtfoods you can (still) enjoy on the diet. Other foods and drinks that boost sirtuin include green tea, onions, celery, parsley, arugula, kale, walnuts, buckwheat and citrus fruits. Meet Jung Ho-yeon, the breakout star of Netflix’s Squid Game View this post on Instagram A post shared by Ayleen (@cookingwithayleen) There’s some research to suggest that sirtuin-boosting foods can help mediate metabolism and could have life-lengthening benefits, though there’s not yet enough data to fully understand how that might work. Proponents of sirtfoods have also cited the fact that many of them (such as wine and leafy greens) are common in so-called Blue Zones, areas of the world where people tend to live the longest. Many of these foods are high in healthy compounds, including vitamins and micronutrients called polyphenols, substances found in plant foods that research suggests can have antioxidant and anti-inflammatory effects, helping to reduce the risk of many chronic illnesses and ailments associated with ageing. Meet Vinod Channa, the man who helped Anant Ambani lose 108kg in 18 months Be careful with your calorie count While these foods are individually healthy and fine to include in your diet, there’s no evidence that specifically eating only sirtfoods is good for you. Plus, there’s a lot of foods and nutrients that are left out of that list, including protein sources from chicken to beans, healthy fats and whole grains. And the calorie limitations of the diet could be a problem, too. The plan follows a seven-day cycle of just 1,000 calories a day for the first three days and 1,500 calories a day for days four through seven. The 5 most awkward curtsies to royals – plus one of the cutest Fewer than 1,500 to 1,200 calories can put you at risk of malnutrition, according to Harvard Health. Any diet that cuts calories so strictly is also very difficult to follow in the long term, says nutritionist Rachael Hartley. “A thousand calories is under the daily amount recommended for a two-year-old. So for an adult eating that and expecting to fuel their day, you might not keel over, but you’re not going to have the energy to perform at your best,” Hartley said. Jennifer Lopez or Ben Affleck – who has the higher net worth? It can also be risky for people with a history of eating disorders or who otherwise have a fraught relationship with food. So, while it’s fine to include a little more green tea, berries, and yes, even wine with your daily meals, it’s still best to consult a nutrition expert, such as a registered dietitian, before jumping into the latest fad diet, whether it’s celebrity endorsed or not. This article originally appeared on Business Insider Want more stories like this? Sign up here. Follow STYLE on Facebook , Instagram , YouTube and Twitter .