It's no surprise that the "sirtfoods" diet trend — featuring dark chocolate and red wine — is rumored to be a hit with celebs like Adele and Pippa Middleton, but nutrition experts aren't as enthusiastic.
"Sirtfoods" like green tea, kale and blueberries purportedly activate sirtuins, proteins that some research has linked to regulating inflammation and burning fat. But the diet also calls for only eating 1,000 calories a day for the first week. If you're curious if the diet delivers on its promises, keep reading as the experts weigh in.
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So, What Is the Sirtfood Diet?
The sirtfood diet gets its name by combining "sirtuins" and "food." It's based on the idea that certain foods can activate proteins called sirtuins, and that this process triggers a bevy of health benefits, including weight loss. The diet includes foods and beverages such as green tea, dark chocolate, apples, citrus fruits, parsley, turmeric, kale, blueberries, capers and red wine, according to its official website.
There are two phases to the sirtfood diet. During phase one, which lasts a week, followers are restricted to 1,000 daily calories for the first three days, then 1,500 daily calories for the next four days. The first three days consist of three sirtfood green juices along with one sirtfood-filled meal. In the four days following, dieters shift to two green juices and two meals.
Read more: How to Find the Best Weight-Loss Diet for You
During phase two of the diet, which spans 14 days, you're encouraged to eat three balanced meals full of sirtfoods each day along with one green juice.
According to the diet's site, this two-phase process can be repeated "whenever you like for a fat-loss boost."
Does Sirtuin Activate a "Skinny Gene?"
You may be wondering, though: Can the sirtfood diet actually help you lose weight and keep it off?
"The diet claims eating sirtuin-boosting foods, such as those high in polyphenols, will activate a 'skinny gene' pathway usually induced by exercise and fasting," Kristen Smith, RD, LD, dietitian and spokesperson for the Academy of Nutrition and Dietetics, tells LIVESTRONG.com. "One of the claims is you will lose 7 pounds in seven days — rapid weight loss is always appealing."
Sounds great, but does the sirtfood diet have a solid scientific basis? "Short answer: No," says Ginger Hultin, RDN, another dietitian and spokesperson for the Academy of Nutrition and Dietetics. Despite some preliminary research, Hultin notes: "A sirtuin-activating diet for weight loss is not yet scientifically proven."
Toby Amidor, RD, CDN, dietitian and author of The Healthy Meal Prep Cookbook, agrees. "The idea sounds enticing, but in reality there's little research to back up these claims." The quick weight loss at the start of the diet plan may have more to do with calorie restriction than sirtuins, she adds.
"A sirtuin-activating diet for weight loss is not yet scientifically proven."
But that kind of rapid weight loss is neither healthy nor sustainable, according to the Mayo Clinic, which recommends aiming to shave off a more moderate 1 to 2 pounds per week. That way, you're more likely to be losing fat rather than water weight and lean muscle, and less likely to leave yourself open to nutritional deficiencies.
What's more, restricting your calories so low can backfire, causing you to overeat and possibly end up gaining weight, according to the International Food Information Council Foundation.
Are Sirtfoods Really Healthy?
While it may not be a diet that's healthy to follow to the letter, there are plenty of good reasons to include many of the core sirtfoods in a weight-loss plan, including kale, berries, ginger, turmeric, green tea and olive oil.
Here's a primer on some of the top sirtfoods — just be sure to enjoy them in the context of a balanced diet with a variety of other healthy foods.
1. Chia Seeds
In the world of sirtfoods, chia seeds are noted to be a moderate sirtuin-activating food that the authors of The Sirtfood Diet describe in their book as the equivalent of taking a walk versus getting in an intense sweat session at the gym.
There's no reliable evidence to support this claim, but there's no debate that chia seeds pack a ton of nutrition into a small package, making them an efficient way to load up on key nutrients like fiber (about 10 grams per ounce) and folate (about 14 micrograms), per the USDA. Chia is also a good source of plant protein. Just sprinkle the seeds over a smoothie bowl, add to smoothies or mix into oatmeal.
In a study published April 2017 in Biochemistry and Molecular Biology, researchers used a computer model to see if cinnamon activated sirtuins and found promising connections. This doesn't prove anything yet, but it's an interesting building block for future research.
But cinnamon still makes the sirtfoods list because it offers powerful polyphenols, which are plant compounds with antioxidant and anti-inflammatory properties. And there's some research that appears to suggest that cinnamon can help control blood sugar by slowing carb digestion and improving how the body responds to insulin, according to the Mayo Clinic.
Cinnamon goes great in coffee, hot chocolate, collard greens, roasted squash, soups, smoothies and spice rubs for lean pork.
Read more: 10 Herbs and Spices to Help You Lose Weight
The proposed sirtuin-activating nutrient in cocoa is epicatechin, a powerful kind of antioxidant also found in tea and grapes.
As a polyphenol-rich food, cocoa may help promote healthy blood flow, per an April 2017 Cochrane review — not that you needed another reason to enjoy chocolate. Just remember that the benefits are from the cocoa plant, not all the added sugar, salt and fat in processed candy bars. Look for the highest percentage dark chocolate you can find to reap the most benefits.
4. Olive Oil
The supposed sirtuin-activating polyphenols in extra virgin olive oil are oleuropein and hydroxytyrosol. What we do know is that olive oil is a key component of the heart-healthy Mediterranean diet, which can also support a weight-management plan.
It's also rich in monounsaturated fats, which can help improve cholesterol levels, especially when they replace saturated fat or refined carbs, per the American Heart Association.
Read more: Is Extra-Virgin Olive Oil Better Than Olive Oil?
Berries such as raspberries, strawberries and blackberries are rich in polyphenols, so it comes as no surprise that berries are antioxidant superstars, per the Mayo Clinic. They're also rich in fiber and vitamin C.
Fresh berries are excellent on their own, and frozen berries can be conveniently enjoyed year-round in a crowd-pleasing smoothie or an unexpectedly fresh salsa.
A cup of kale has double the day's vitamin A and more vitamin C than an orange, per the USDA.
To prepare kale, remove stems, roll and slice crosswise into ribbons (chiffonade) before massaging for a few minutes with your favorite dressing. Add these marinated kale ribbons and whatever fruit you have around with your favorite grain, such as farro, wheat berry, sorghum or freekeh, for a quick and healthy whole-grain salad.
7. Red Wine
Red wine made its name in health circles for containing the polyphenol resveratrol. Observational research in humans suggests that moderate intake could have health benefits for heart health and potentially for longevity and brain health, too, according to Harvard Health Publishing.
As a traditional part of the Mediterranean diet, it's meant to be enjoyed with food in appropriate amounts (e.g., one 5-ounce glass for women per day). Of course, it's not right for everyone, and there are many other ways to eat and drink for good health for anyone who prefers to abstain from wine for any reason.
Read more: 7 Surprising Health Benefits of Red Wine
- Sirtfood Diet: "About Us"
- Mayo Clinic: "Why do doctors recommend a slow rate of weight loss? What's wrong with fast weight loss?"
- International Food Information Council Foundation: "3 Reasons to Swipe Left on the Sirtfood Diet"
- USDA FoodData Central: "Seeds, chia seeds, dried"
- Biochemistry and Molecular Biology: "Cooperative binding of cinnamon polyphenols as activators of Sirtuin-1 protein in the insulin signaling pathway"
- Mayo Clinic: "Is it true that cinnamon can lower blood sugar in people who have diabetes?"
- American Heart Association: "Monounsaturated Fat"
- Mayo Clinic: "Slide show: Add antioxidants to your diet"
- USDA FoodData Central: "Kale, raw"
- Harvard Health Publishing: "Resveratrol—the hype continues"
- Cochrane: "Effect of cocoa on blood pressure"