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What is the Sirtfood Diet?

Sally Kuzemchak, MS, RD - Blogs
By Sally Kuzemchak, MS, RDRegistered dietitianJune 19, 2020

It’s an all-too-familiar cycle: Celebrity loses weight. Tabloid press freaks out. Diet used by that celeb starts showing up in hashtags and headlines everywhere. Regular people try diet and hate it. Repeat.

It happened with Kelly Clarkson (remember the lectin-free diet that demonized beans, tomatoes, and oats?). Now it’s happening with Adele. When new photos of the Grammy-award-winning singer recently emerged, revealing what appeared to be a significant weight loss, everyone clamored to find out how she did it.

Though it hasn’t been confirmed, rumor has it that Adele followed something called the Sirtfood Diet, which seems to have originated in a UK gym.

The premise of the diet is the claim that beneficial plant compounds called polyphenols switch on certain proteins called sirtuins that mimic the effects of fasting and exercise (the diet’s creators refer to this as turning on the “skinny gene pathway”). Many plant foods contain polyphenols, but their top 20 “sirtfoods” include things like kale, strawberries, red onion, and walnuts but also dark chocolate, red wine, and coffee.

The first week of the diet, which they refer to as the “hyper-success phase”, involves drinking 2-3 green juices (yes, you’ll need a juicer) and eating up to two meals a day for a suggested total of 1,000-1,500 calories a day (1,000 for the first three days; 1,500 for the last four). During the next two weeks of the “maintenance phase”, it’s suggested you consume three meals per day, one green juice, and 1-2 “Sirtfood Bites” (a snack bite recipe they provide), for about 1,500-1,800 calories a day. You're supposed to follow the recipes in the book, which are rich in sirtfoods. But while they sound tasty enough--a stir-fry made with whole grains, veggies, turmeric, and tofu or a kale salad made with chicken and vegetables and a dressing of olive oil and herbs--the bottom line is that if you’re following the suggested low-calorie plan, you're simply not eating much food. My guess is that many people will likely feel unsatisfied and hungry.

Besides the fact that there is no research to support the theory of a magical gene pathway causing weight loss, I can’t help but wonder: If these foods are so special, why does the diet still require such a low-calorie plan to work? The authors claim you can lose seven pounds in the first seven days, but eating just 1,000-1,500 calories a day for a week will lead to weight loss for a lot of folks (likely a lot of water weight), no matter what they’re eating.

What comes next? In my opinion, the authors are pretty vague on that. You’re supposed to keep eating a sirtfood-rich diet, and they offer an extended list to choose from. But my hunch is that many people will also experience intense cravings and overeating--common after prolonged calorie deprivation, which is why fad diets like this one are typically more hurt than help.

Yes, eating a diet rich in polyphenols is a good thing. Foods like kale, apples, citrus, extra virgin olive oil, and dark chocolate all contain natural plant compounds that may protect health in various ways. So go ahead and put those--and lots of plant foods in general--in your meals and snacks. Just don’t count on them switching on a “skinny gene pathway” that magically melts off pounds.

Correction: The post has been corrected to clarify the suggested calorie intake for weeks 1-3 of the diet, and to properly reflect the duration of the diet.

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About the Author
Sally Kuzemchak, MS, RD

Sally Kuzemchak is a registered dietitian in Columbus, Ohio. An award-winning reporter and writer, Sally has been published in magazines such as Health, Family Circle, and Eating Well and is a Contributing Editor to Parents magazine. She is the author of the book The 101 Healthiest Foods For Kids. She blogs at Real Mom Nutrition, a "no-judgments" zone all about feeding families.

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