Touted as a fat-melting diet, it severely restricts calories.

By Claire Gillespie
January 29, 2020
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While the world has been waiting for Adele to drop new music, it’s been getting just a little bit obsessed about her weight. There’s no doubt that she looks incredible (um, hasn’t she always?) and it’s rumored to be down to the Sirtfood Diet.

Lexi Larson, a 19-year-old from Hingham, Massachusetts, told People that she met Adele on vacation in Anguilla and that the music superstar told her she had “lost something like 100 pounds,” describing it as a “crazy positive experience.”

Adele hasn’t confirmed that her weight loss is down to the Sirtfood Diet (or any other diet), but she is featured on the official Sirtfood Diet website with the words, “Adele’s top-secret fat-melting diet.”

So what’s the big deal about the Sirtfood Diet? 

The eating plan is based on polyphenols, natural compounds found in plant foods that help to protect the cells in the body from inflammation or death through illness. According to health consultants Aidan Goggins and Glen Matten, who devised the Sirtfood Diet, a small group of polyphenols can mimic the effects of fasting and exercise by activating the body’s sirtuin (aka “skinny”) genes.

“Based on consuming a certain list of healthy, polyphenol-rich foods, the Sirtfood Diet promises weight and fat reduction without muscle loss,” says New York-based dietitian-nutritionist Tanya Freirich, RD, at Sweet Nova.

What’s the plan? 

There are two phases to the Sirtfood diet; the first lasts for one week and the second for two weeks. During the first three days of the plan, you’re restricted to 1,000 calories from one meal of sirtfoods and three green juices. For the rest of the first week, you can consume two green juices and two sirtfood meals per day. During phase two, the daily meal plan consists of three sirtfood meals and one green juice.

Beyond the initial three-week “jumpstart” period, Goggins and Matten recommend continuing to include sirtfoods in your meals to continue seeing results.

What does it promise?

“If you don’t deviate from the plan, the Sirtfood Diet promises a seven-pound weight loss in the first week (without losing muscle mass),” says Freirich. “It also claims to have anti-aging effects, to help improve memory and blood sugar control and reduce the risk of chronic disease.”

But does it deliver?

The research on the role of sirtuin is pretty thin—mostly laboratory studies involving yeast, lab animals, and human stem cells. One study, published in 2013 in the journal Oxidative Medicine and Cellular Longevity, suggests polyphenol consumption has the same beneficial effect on human metabolism as calorie restriction. But until this dietary approach is actually tested in human clinical trials, it’s impossible to say with any certainty how people might fare.

What can you eat? 

While some sirtfoods are standard in any supermarket or health food store (and might already be in your kitchen), others may not be so easy to find.

“Sirtfoods include kale, dark chocolate, red wine, cocoa powder, turmeric, onions, parsley, garlic, walnuts, and strawberries,” Freirich says. “Most of the ingredients are easy to find and are well-known as healthy choices. However, additional ingredients may be harder to source, like lovage, buckwheat, and matcha green tea powder.”

What can’t you eat? 

Officially, no foods are “banned” on the Sirtfood Diet, but the calorie restriction is serious—particularly during the initial three days, when you’re limited to 1,000 calories.

To put that in perspective, 1,000 calories is the recommended intake for a sedentary 2- to 3-year-old, according to the USDA Dietary Guidelines for 2015-2020,

Are there any drawbacks? 

The toughest part of the Sirtfood Diet is calorie restriction and the reliance on green juice, and this could be unsafe for certain groups of people, Freirich says. She wouldn’t recommend this diet for people on some medications, like Coumadin, or with health conditions like diabetes. She’d also give it a miss if you’re training extensively or are pregnant or breastfeeding.

“Generally, I don’t recommend any diets that rely on overly restrictive external rules,” Freirich adds. “However, many of the recommended ‘sirtfoods’ are health-promoting, and I’d recommend people incorporate these in their meals. As always, I strongly encourage people to listen to their body's hunger and satiety cues for guidance on when and how much food to eat.”

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