The Sirtfood Diet: What You Need To Know & Is It Science-Backed?

Contributing Health & Nutrition Editor By Stephanie Eckelkamp
Contributing Health & Nutrition Editor
Stephanie Eckelkamp is a writer and editor who has been working for leading health publications for the past 10 years. She received her B.S. in journalism from Syracuse University with a minor in nutrition.
A bottle of green juice and broccoli florets
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Any diet that claims to turn on your "skinny genes" is sure to turn a few heads—and most likely set off your B.S. detector. But that's exactly what the Sirtfood Diet claims to do.

This diet, which first hit the scene in 2016, experienced a surge in popularity when news broke that Adele, Pippa Middleton, and other celebrities purportedly follow the plan to lose weight and boost energy with foods like kale, red wine, dark chocolate, and matcha—and it's only been gaining steam. In fact, Google just announced that the Sirtfood Diet was the seventh-most searched for diet in 2019

But how exactly is this diet formatted, and what's a "sirtfood," anyway? Spoiler: This plan may be loaded with nutrients, but some experts say it's not entirely based on solid science. Here's what you need to know. 

What is the Sirtfood Diet?

The Sirtfood Diet was developed by U.K.-based nutritionists Aidan Goggins and Glen Matten, both of whom hold master's degrees in nutritional medicine. Their book, The Sirtfood Diet, was published in the U.S. in 2017 and features a plan to help you "lose seven pounds in seven days while experiencing lasting energy and enjoying the foods you love including chocolate, red wine, strawberries, and more."

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The premise of the Sirtfood Diet.

The basic premise of the Sirtfood Diet is that certain foods, dubbed "sirtfoods," can essentially mimic the proven benefits of caloric restriction and fasting by way of activating sirtuins—proteins in the body (ranging from SIRT1 to SIRT7) that regulate biological pathways, turn certain genes on and off, and help protect cells from age-related decline. Activation of SIRT1, for example, has been shown in some lab and animal studies to induce the formation of new mitochondria, extend life span, and improve oxidative metabolism, which may support weight loss and maintenance.  

Because fasting and intense caloric restriction is really hard (and often, not advisable), Goggins and Matten developed their dietary plan—focused on eating loads of "sirtfoods"—as an easier way to stimulate the body's sirtuin genes (sometimes referred to as "skinny genes") and thus ramp up weight loss and promote overall health.

What makes something a "sirtfood"?

Some "sirtfoods" that Goggins and Matten mention in their book include green tea, berries, cocoa powder, turmeric, kale, onions, parsley, arugula, chilies, coffee, red wine, walnuts, capers, buckwheat, and olive oil. All of these foods contain specific polyphenol compounds (quercetin, resveratrol, kaempferol, etc.) that have, in fact, been found in scientific studies to increase sirtuin activity. So, in this regard, the diet is at least somewhat based on science.

The problem, however, is that these foods may not contain sufficient levels of these polyphenols to actually activate sirtuins in any meaningful way. Many of the studies linking polyphenol compounds to increased sirtuin activity have only been done on highly concentrated forms of these compounds.

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How the Sirtfood Diet is structured.

The Sirtfood Diet is broken down into two basic phases (which are outlined in greater detail in the book):

Phase One lasts for seven days. For the first three days, the diet calls for consuming three sirtfood green juices and one meal rich in sirtfoods—for a total of 1,000 calories per day. Days four through seven each consist of two green juices and two meals—for a total of 1,500 calories per day. This is the part of the plan in which Goggins and Matten claim you can "lose seven pounds in seven days."

Phase Two is a 14-day maintenance phase meant to "help you lose weight steadily." You can have three sirtfood-rich meals plus one green juice per day.

According to Goggins and Matten, these two phases can be repeated as often as you'd like for a weight loss boost. Following these initial three weeks, you're encouraged to continue "sirtifying" your meals by eating a diet rich in sirtfoods keeping up with your daily green juice.

What do functional nutrition experts have to say about it?

Overall, expert feedback on the Sirtfood Diet is mixed. The good news: The diet does seem to be loaded with foods that are healthy. "There is extensive research that highlights the many benefits of some of the foods called out on this diet, like coffee, green tea, dark chocolate, and dark leafy greens," says Jessica Cording, R.D., registered dietitian and health coach.

Many of these foods may also support healthy weight loss, says Frances Largeman-Roth, R.D., but whether or not they promote weight loss by activating sirtuins remains to be proved. According to Largeman-Roth, while studies have shown the importance of sirtuins and sirtuin-boosting compounds on metabolic pathways, there is no science behind the ability of specific foods to boost sirtuin levels. 

"The foods promoted on the diet are ones that fight inflammation and would be beneficial for anyone to add to their diet but not because they boost sirtuins," she says. "Just because a food contains a certain nutrient linked to metabolism doesn't mean that food causes automatic weight loss—there is no way to turn on a 'skinny gene' with food."

Additionally, while these "sirtfoods" are indeed healthy, Largeman-Roth says someone would want to make sure they're also rounding out their meals with healthy fats and proteins. 

As for the structure of the diet, it may not be perfect, but Cording thinks it could be an approachable option for people who are interested in a weight loss plan that has some structure and offers room for flexibility and customization. "I appreciate that it's a 'diet of inclusion' versus one focused primarily on restricting foods," she says. 

That said, Cording admits that the juice-heavy initial part of Phase One is a bit lower in calories than what she'd typically recommend, but the later phases, which include a higher calorie goal and solid food, are somewhat more sustainable. 

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The bottom line.

Go ahead, eat more "sirtfoods," but maybe think twice before actually committing to the Sirtfood Diet. Both Cording and Largeman-Roth agree that plant-based, antioxidant-packed "sirtfoods" can make a powerfully healthy addition to your diet and help support weight loss or healthy weight maintenance. But as for the diet itself, there's no good science to suggest it will activate your "skinny genes" or have a meaningful impact on sirtuins.

Any weight loss from following a Sirtfood Diet could likely be chalked up to eating fewer calories, more fiber, and consuming more nutrients in general—which you could experience with any number of dietary approaches. If you do want to try it, make sure you don't forget to include plenty of healthy fats and protein (a Mediterranean-style diet bolstered with additional "sirtfoods" would be a good place to start), and consider consulting with a registered dietitian for help customizing a plan that's tailored for your specific needs and goals.

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