The sirtfood diet includes chocolate, red wine, and has celebrity followers like Adele. But is it too good to be true?

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"Sirtfood" sounds like something developed by aliens, brought to earth for human consumption in the hopes of gaining mind control and world domination. In actuality, sirtfoods are simply foods high in sirtuins. Uh, come again? Sirtuins are a type of protein that studies on fruit flies and mice have shown regulate metabolism, increase muscle mass, and burn fat.

The Sirtfood Diet book (Buy It, $12, amazon.com) was first published in the U.K. in 2016, and the U.S. release of the book a year later sparked more curiosity about the plan. According to the book, this plan can help you burn fat and boost your energy, priming your body for long-term weight-loss success and a longer, healthier, disease-free life. All that while drinking red wine — score.

The diet garnered even more hype when Adele premiered her slimmer figure at the Billboard Music Awards in 2016. Her former trainer Pete Geracimo, who worked with the star from 2012 to 2016, is reportedly a huge fan of the sirtfood diet. Geracimo apparently encouraged Adele to follow the plan in 2016, Aidan Goggins, co-author of The Sirtfood Diet, recently told The New York Post. And, according to Goggins, who has been in contact with the singer's friends, Adele has reportedly continued to follow the sirtfood diet to a T over the last few years. She's since been rumored to have lost about 100 pounds, according to People. (Related: People Are Heated About the Headlines Celebrating Adele's Weight Loss)

While Adele has yet to personally confirm her diet with the public, her recent body transformation is stirring up conversations about the eating plan and inspiring people to try it themselves. But before you burn through your savings stocking up on sirtfoods, read up on what exactly it can and can't do for your health.

What is the sirtfood diet, and how does it work?

At its core, the key to losing weight is pretty simple: Create a calorie deficit either by increasing your calorie burn through workouts or decreasing your caloric intake. But, by following the plan laid out in The Sirtfood Diet, written by Goggins and fellow nutrition expert Glen Matten, you could potentially lose weight without the need for intense calorie restriction or exercise. The way to do it, the authors argue, is by adding healthy sirtfoods to your diet.

cropped shot of woman holding glass of red wine isolated on pink with kale and chocolate
Credit: Adobe Stock - Design: Alex Sandoval

Sirtfoods are rich in polyphenols, which are naturally occurring compounds found largely in fruits, vegetables, and cereals. These polyphenols cause sirtuins — a family of proteins that play a key role in regulating cell health — to activate a pathway that "switch[es] on your body's fat-burning powers," according to Goggins and Matten.

In 2015, Goggins and Matten say they conducted a study to test the effectiveness of sirtuins, according to their book. (However, the results of their study have not been published in an academic journal and appear only in The Sirtfood Diet.) The 39 participants lost an average of seven pounds in seven days, the co-authors wrote. Those results sound impressive, but it's important to realize this is a small sample size studied over a short time.

Experts also have their doubts about the sirtfood diet's lofty promises. "The claims made are very speculative and extrapolate from studies which were mostly focused on simple organisms (like yeast) at the cellular level. What happens at the cellular level does not necessarily translate to what happens in the human body at the macro level," says Adrienne Youdim, M.D., the director of the Center for Weight Loss and Nutrition in Beverly Hills, CA.

What are sirtfood diet foods?

The book contains a list of the top 20 sirtfoods, and you can find even more on the sirtfood diet website. Examples of sirtfoods include:

  • Buckwheat
  • Arugula
  • Chilies
  • Coffee
  • Green tea, particularly matcha
  • Medjool dates
  • Red wine
  • Turmeric
  • Walnuts
  • Cocoa
  • Red onions
  • Parsley
  • Extra virgin olive oil
  • Kale
  • Red chicory

Dr. Youdim notes that while sirtfood diet foods tend to be generally healthy, they won't necessarily promote weight loss on their own.

The Sirtfood Diet Book
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What does the sirtfood diet entail?

The diet is executed in two phases. Phase one lasts seven days, and during the first three days, it restricts calories to 1,000 per day, consisting of three green juices and one sirtfood-approved meal. On days four to seven, the daily allotment is raised to 1,500 calories per day with two green juices and two meals. Phase two is a 14-day maintenance plan that focuses more on sensible portions and well-balanced meals than calories. The maintenance plan features three sirtfood-rich meals and one green juice daily, according to the sirtfood diet website. Followers are also encouraged to complete 30 minutes of activity five days a week — per government recommendations — but it isn't the main focus of the plan. (Related: What You Need to Understand About Exercise and Calorie Burn)

Even though the sirtfood diet brands itself as, well, a diet, the founders encourage followers to think of it as a "way of life." After the first three weeks, they recommend continuing to eat a diet filled with sirtfoods and drinking a daily green juice. According to Goggins, that's exactly what Adele has done in the last few years. "[Her friends] described a typical day of ‘a green juice in the morning before workout’ and meals being stuff like shrimp stir-fry with buckwheat noodles, chicken with kale," Goggins told The New York Post. "Even her treats were our exact recipe for sirtfood bites [chocolate bites made with cocoa powder, dates, turmeric, and walnuts]. It was the epitome of the diet."

What are the sirtfood diet's benefits?

You will lose weight if you follow this diet closely. "Whether you're eating 1,000 calories of tacos, 1,000 calories of kale, or 1,000 calories of snickerdoodles, you will lose weight at 1,000 calories!" says Dr. Youdim. But she also points out that you can have success with a more reasonable calorie restriction. The typical daily caloric intake of someone not on a diet is 2,000 to 2,200, so reducing to 1,500 is still restricting and would be an effective weight-loss strategy for most, she says.

What are the drawbacks of the sirtfood diet?

The plan is strict with little wiggle room or substitutions, and weight loss can be maintained only if the low caloric intake is also maintained, making it difficult to adhere to long-term. That means any weight you lost in the first seven days is likely to be gained back after you finish, says Dr. Youdin. Her main concern? "Limiting protein intake with juices will result in a loss of muscle mass. Losing muscle is synonymous with dropping your metabolic rate or 'metabolism,' making weight maintenance more difficult," she says. (Related: Can a 3-Week Juice Cleanse Cause Brain Damage?)

Final Thoughts

Overall, Dr. Youdim would not recommend the sirtfood diet. There are other ways that you can reduce calorie intake without being so restrictive in the foods that you eat. With that being said, the diet is not necessarily "unhealthy," so she wouldn't necessarily caution against it if a patient found success.

If you choose to follow the sirtfood diet, be sure to eat plenty of protein and vary the foods you eat to prevent vitamin deficiencies. At the end of the day, though, it's clear that the diet is pretty strict and its effectiveness has not been adequately proven. So whether you want to lose weight or live your life just like Adele, you're best off talking it over with your doctor to make sure it's a good fit for you.