Getting to Know the Sirtfood Diet

Last year, famous British singer Adele shocked many when she revealed that she had been on a strict diet which helped her lose a large amount of weight. But the diet wasn’t well-known, and many had their reservations about its efficacy long-term and concerns about its limitations. The diet in question is called the Sirtfood Diet.

So, we spoke with Kaylee Jacks, a sports nutritionist at Texas Health Sports Medicine, to understand more about it, if it’s effective long-term, and most of all, if it’s safe.


What It Is

The Sirtfood Diet isn’t just an odd name, it refers to a group of proteins called sirtuins or SIRTs. These seven proteins have been shown to regulate a variety of functions, including metabolism inflammation and lifespan.

Certain plant compounds may be able to increase the level of these seven proteins in our body, and foods containing them have been dubbed “sirtfoods,” hence the name of the diet.

The “top 20 sirtfoods” according to the diet include:

  • kale
  • red wine
  • strawberries
  • onions
  • soy
  • parsley
  • extra virgin olive oil
  • dark chocolate (85% cocoa)
  • matcha green tea
  • buckwheat
  • turmeric
  • walnuts
  • arugula (rocket)
  • bird’s eye chili
  • lovage
  • Medjool dates
  • red chicory
  • blueberries
  • capers
  • coffee

In addition to eating these foods, calorie restriction is also integrated into the diet. Therefore, the diet is split into two phases. Phase 1, which is dubbed the “green juice” and phase 2, which is dubbed the “maintenance” phase. The green juice is comprised of kale, arugula, parsley, celery, apple, ginger, lemon and matcha powder.


How It Works

During the first three days of the diet (Phase 1), you’ll consume a maximum of 1,000 calories a day. You’ll consume three green juices a day and one meal that focuses on sirtuin-rich foods. On the fourth day, you’ll increase your calories to 1,500 and you can replace one green juice with another sirtuin-rich meal. You’ll continue this for another three days.

It’s during this phase that the creators of the diet “promise” you will lose seven pounds, or a pound a day.

After the first week, you will enter into phase two or the maintenance phase. You’ll increase your meals to three a day and decrease your juices to just one a day. You also now have the option of including two Sirtfood diet bite snacks into your day, such as dates or walnuts. There is also no calorie requirement or limit during this phase.


Is It Effective Long-Term?

The diet is famous for allowing red wine and chocolate, and who wouldn’t be a fan? But similar to Whole 30, its creators insist that it’s not a fad, but rather a lifestyle, claiming that “sirtfoods” are the secret to unlocking fat loss and preventing disease.

But its effectiveness long-term has yet to be proven. There is no concrete evidence so far that the diet has a more beneficial effect on weight loss than any other calorie-restricted diet. Moreover, there isn’t any diet or category of foods that “turn on skinny genes,” as the creators of the diet suggest the sirtfoods diet does.

Nevertheless, the Sirtfood Diet book reports the results of a pilot study conducted by the authors, involving 39 participants from their fitness center.

For one week, the participants followed the diet and exercised daily. At the end of the week, participants lost an average of 7 pounds (3.2 kg) and maintained or even gained muscle mass.

Yet, these results aren’t too surprising, says Jacks, since restricting your calorie intake to 1,000 calories and exercising at the same time will almost always cause weight loss.

“Any diet that eliminates or limits a nutrient and/or food groups put you at risk of being under fueled (not enough overall calories) and/or malnourished (not obtaining adequate nutrients),” she warns. “And a caloric intake in that range is considered too low for most adults, much less active adults.”

The study also did not follow participants after the first week to see if they gained any of the weight back.

In addition, there’s little guidance on what to do after your three weeks are up. You’re encouraged to keep eating a diet rich in sirtfoods and continue with the green juices, but you’re also open to start incorporating more foods into your diet to help make it more manageable beyond the three weeks. But even then, the foods you’re allowed to start including can still feel restrictive. For instance, the diet says you can expand your fruit intake beyond just strawberries to other berries, such as raspberries or blackberries. Additionally, instead of just consuming walnuts, you can add pistachios and peanuts into your rotation of snacks.

The Takeaway

The Sirtfood diet is, at its core, a calorie-restricted diet. Consuming fewer calories than you normally do will almost always result in weight loss, regardless of the types of foods you’re eating. But that being said, there’s little evidence that eating sirtuin-rich foods hold the key to unlocking fat-burning genes

Instead, Jacks recommends focusing on eating a healthy, balanced diet and exercising appropriately. You can still splurge on certain foods, such as coffee and wine, but in moderation.

“There is not a best ‘one size fits all’ for diets. A healthy balance or a variety of nutrients in adequate amounts that is specific to each individual is ideal,” she adds.

If you’re considering changing your diet, it’s recommended you consult with a registered dietitian or a health professional before starting. If you need help getting started, visit to learn more about nutrition counseling to set you on the right path.

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