Adele’s Sirtfood Diet

I recently got an email newsletter from TRC Natural Medicines. One of the articles was “Understanding the Hype Behind Adele’s Sirtfood Diet.”

It’s brief enough to quote in its entirety:  

“English singer-songwriter Adele has made headlines in recent months for her dramatic weight loss. You might start getting questions about the diet she followed—it’s called the Sirtfood Diet, and it’s getting a lot of press. So what is the diet? And what should you tell patients? 

The Sirtfood Diet was developed by Aidan Goggins and Glen Matten—two nutritionists in the UK. The diet emphasizes eating foods that contain sirtuin-activating compounds (STACs)—chemicals that have been shown to activate a group of enzymes called sirtuin, or what the authors of the diet refer to as ‘the skinny gene.’ 

These foods are called ‘sirtfoods.’ According to the authors, eating sirtfoods activates the same fat burning mechanisms that occur when the body fasts, without the fasting. It’s also been theorized that increasing the activity of certain sirtuins might help treat disease and slow aging. But what does the evidence say?

Unfortunately, there isn’t any clinical evidence to report. In addition to focusing on sirtfoods, the diet also requires significant calorie restriction, particularly in the first week. This calorie restriction is likely to result in short-term weight loss, but it’s unclear what long-term benefits, if any, the diet offers. If patients ask you about this diet, tell them that foods considered ‘sirtfoods’ are certainly healthy and safe options. But there isn’t any clinical evidence supporting the Sirtfood Diet plan. Until more research is available, advise patients to focus on healthy lifestyle choices, and point them towards dietary modifications with more supportive clinical evidence, such as the. Mediterranean or ketogenic diets.”  

Having never heard of the Sirtfood Diet and having barely heard of Adele, I wanted to look into it. I thought it would be a good opportunity to rant about celebrities who give advice about health and diet. I will never understand why people trust celebrities over doctors on these matters, but in this case the question was moot. Adele is not advising people to try the diet, and it’s not clear that she follows the diet herself. She’s not talking.

Many people have noticed Adele’s recent dramatic weight loss. An article in Marie Claire says Adele “apparently” achieved it by following the Sirtfood Diet, which was also adopted by celebrities such as Lorraine Pascale and Jodie Kidd. How much did she lose? Accounts differ. The Marie Claire article first says she was “reportedly” seven stones lighter at the Oscars afterparty, after photos of her on holiday on a beach in Anguilla after Christmas allegedly showed she had lost three stones (a stone is a British unit of weight equivalent to fourteen pounds). Other sites credit her with losing different amounts, ranging from “nearly 40 pounds” to 100 pounds. People reported a fan’s account of a conversation she had with Adele where the singer allegedly told her she had lost “something like 100 pounds.” It admitted that Adele “hasn’t revealed how exactly she’s lost the weight.” It reports that “many outlets” have claimed she is following the Sirtfood Diet but that she has never confirmed it. She has said that she has upped her exercise regimen, and her personal trainer Pete Geracimo is known to be a fan of the Sirtfood diet. The Daily Mail reported that she used green juices and a calorie limit of 1000 calories a day. Insider speaks of the Sirtfood diet as her “rumored weight-loss plan.” Prevention promised to reveal “everything we know about Adele’s weight loss transformation,” but it doesn’t reveal much.

This strikes me as just a lot of gossip, rumors, and tabloid fodder; there’s no credible evidence that Adele followed the diet or has given it her celebrity endorsement. Whatever the truth behind the rumors, she is to be congratulated for achieving her goal and losing weight. But what exactly is the Sirtfood Diet?

The diet was created by two health consultants whose focus has been on healthy eating rather than on weight loss. Their plan is supposed to turn on your “skinny gene” and regulate metabolism, inflammation, and life span. It supposedly maintains muscle mass and protects you from chronic disease. Its popularity is partly due to the fact that it allows chocolate and wine.

The Diet Plan

Week one starts with 1000 calories, three sirtfood green juices a day, and one sirtfood-rich meal.

Week two increases the calorie limit to 1500, with two sirtfood green juices and two sirtfood meals a day.

Once you have achieved the desired weight loss, you should continue to eat sirtfoods and drink green juices, but the amounts are no longer specified.

The Top Twenty Sirtfoods Are:

  • Apples
  • Citrus fruits
  • Red wine
  • Buckwheat
  • Walnuts
  • Dark chocolate
  • Medjool dates
  • Parsley
  • Capers
  • Blueberries
  • Green tea
  • Soy
  • Strawberries
  • Turmeric
  • Olive oil
  • Red onion
  • Rocket (arugula)
  • Kale
  • Coffee

 Sirtfood Green Juice

Preparing the green juice requires a juicer, not a blender, and the ingredients must be weighed on a kitchen scale.

  • 75 grams (2.5 ounces) kale
  • 30 grams (1 ounce) arugula (rocket)
  • 5 grams parsley
  • 2 celery sticks
  • 1 cm (0.5 inches) ginger
  • half a green apple
  • half a lemon
  • half a teaspoon matcha green tea

Juice all ingredients—except for the green tea powder and lemon—together and pour them into a glass. Juice the lemon by hand, then stir both the lemon juice and green tea powder into your juice.

The Evidence

There isn’t any. 

Caveats

Anything that reduces your calorie intake that much will probably produce similar weight loss, but there are plenty of other ways to do that. There are other calorie-restricted diets that are supported by evidence from clinical studies. I don’t know about you, but the green juice doesn’t sound very appetizing to me. There is concern that the diet may reduce intake of other important nutrients. 

The Bottom Line

The idea that sirtfoods have health advantages is an untested hypothesis. I don’t plan to test it, and I’m not convinced that Adele did either.

This article was originally published as a SkepDoc’s Corner column on the  CSI website

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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