Fans of Grammy-winning songstress Adele, who recently celebrated her 31st birthday, have been keeping up with Adele’s weight loss via her Instagram profile since early 2019. But what fans might not know, is that it seems the British recording artist may be following an under-the-radar diet plan known as the Sirtfood Diet, which is designed to supercharge your metabolism.
According to People, Adele hired a personal trainer in 2019 to help her get into a new fitness routine, but reports have long linked her weight loss to following the relatively new diet. She’s lost more than 40 pounds by following the program over the last four years, per The Sun (although the singer hasn’t confirmed any of this). And she’s not the only Brit who swears by this diet, either — Pippa Middleton, the Duchess of Cambridge’s sister, also reportedly has experimented with the Sirtfood Diet.
While it certainly may help you lose weight, dieters may be surprised to learn that experts aren’t sure of the Sirtfood Diet’s effectiveness in the long run. Here’s why nutritionists are wary of the Sirtfood Diet in the first place, and how you may be able to adapt the best elements of this fad diet into your own.
What is the Sirtfood Diet?
Believe it or not, this somewhat-controversial diet program was launched by two U.K.-based nutritionists, Aidan Goggins and Glen Matten, after they first published a recipe book by the same name in 2016. The book touts the diet’s effectiveness as it turns on the “skinny gene” by relying on staples that are high in sirtuins, a subset of plant-based proteins that can be found in certain foods and in the body naturally. Increased sirutin levels in the body may help jumpstart your metabolism and reduce inflammation, and has been highlighted for its anti-aging properties, according to this 2013 review published in the Annual Review of Physiology. “In general, it could be a good thing to eat foods that are rich in sirtuin — a gene that may be able to help with weight — like apples, blueberries, and extra virgin olive oil,” says Tracy Lockwood Beckerman, RD, author of The Better Period Food Solution. Foods high in sirtuins, then, have been dubbed “sirtfoods” in the diet plan.
What can you eat on the Sirtfood Diet?
As highlighted in The Official Sirtfood Diet, the diet program is based on a meal plan that is curated to be full of sirtfoods, but curtailed in overall calorie counts. In fact, one of the book’s authors claims that it can help you shed seven pounds in a single week, according to the New York Post. But the book’s meal plan is quite regimented: For the first three days, dieters are expected to consume just 1,000 calories each day that consist of a single meal and two green juices. Later in the first week, dieters will enjoy 1,500-calorie meal plans for four days that are mostly divided between two meals.
The majority of the program asks dieters to create meals that are high in sirtfoods… and not much else. Some of the staples that the diet highlight include many different produce items, including kale, strawberries, onions, parsley, arugula, blueberries, and capers. Some grains, like buckwheat, and walnuts are praised, as are spices like turmeric. Interestingly, beverages like coffee, matcha green tea, and red wine are encouraged — as is a heavy reliance on 85% dark chocolate.
Is the Sirtfood Diet actually healthy for you?
If the diet’s list of celebrated ingredients seems a bit lacking, you’re not alone — many health experts criticize the Sirtfood Diet for being highly restrictive. Beckerman says she has never recommended the Sirtfood Diet to any of her clients because of it’s tight calorie restrictions. “While I applaud the Sirtfood Diet for promoting the consumption of real ingredients, I denounce it for its promotion of calorie restriction and unhealthy eating rules.” Like many other diets that remove food groups from regular consumption, Beckerman says the Sirtfood Diet may indeed lead to “disordered eating” as it also blends elements from intermittent fasting plans into the mix.
McKenzie Caldwell, MPH, RDN, who specializes in women’s nutrition and pregnancy dietary wellness in particular, says that the calorie counts associated with the diet are by far it’s worst quality. “1,000 calories per day is only appropriate for a child between the ages of 2 and 4,” she says, citing current dietary guidelines distributed by the Mayo Clinic. “Not only is this not enough energy to support an adult body, it is not possible to fit in all the macro- and micronutrients an adult needs in that amount of food… The diet may cause weight loss in the short term merely because of it’s caloric restriction.”
Most importantly, however, both nutrition experts agree that there is little to no clinical evidence to support this diet being healthy for sustained weight loss. “There is absolutely no evidence to back up any claims that the Sirtfood Diet has a beneficial effect on healthy weight loss,” Beckerman says. “The creators of the diet claim to have put participants at their own gym on the diet, but this anecdotal supposed study has not been published nor validated by true researchers or scientists.”
The bottom line:
Just like Keto and Whole30, the Sirtfood Diet often radicalizes how you normally eat by asking you to skimp on meals. While all diets often adhere to some form of a calorie-limit, Caldwell says it’s important to consider your own lifestyle and think about what you need throughout the day. “The reality is, there is nothing magical about sirtfoods in particular — being rich in polyphenols, they do have anti-inflammatory properties, but the research doesn’t support them having any extra effectiveness for weight loss.”
If you’re dead set on giving the Sirtfood Diet a try, first experiment by incorporating more of the diet’s signature staples into what you’re already eating at home. “Incorporating polyphenol-rich foods, including those on the sirtfood list, can be helpful in preventing or reducing inflammatory diseases like cardiovascular disease,” she advises. “Skip the initial restrictive steps and prescribed green juices, and instead opt for adding in antioxidant-rich foods to your eating pattern in a way you enjoy.”