Lately, Adele has been making headlines beyond her stunning voice: After stepping out looking slimmer than usual, a frenzy of reports claim that the 31-year-old “Someone Like You” singer lost weight by following the Sirtfood Diet, a calorie-restricting eating plan, after her breakup with her husband Simon Konecki.
This isn’t the first time Adele’s name has been associated with the Sirtfood Diet. Back in 2016, the New York Post claimed the singer lost 30 pounds by eating foods rich in sirtuins, a.k.a. proteins that can be found in certain foods (they also occur naturally in the body). Her former Pilates instructor Camila Goodis also told The Sun that she believed the star’s weight loss was “90%” diet.
Adele hasn’t publicly commented on the rumors swirling around her figure (why should she?!), but her trainer Pete Geracimo (who also works with Pippa Middleton) supposedly likes to put his clients on the Sirtfood Diet.
And as the seventh most Googled diet in 2019, people clearly want to know what it’s all about. Here, dietitians and a doctor explain what the Sirtfood Diet entails, the foods it encourages, and whether or not it’s a legit way to lose weight long-term.
What is the Sirtfood Diet?
The Sirtfood Diet is based on the book by the same name that was written by Aidan Goggins and Glen Matten. The diet focuses on eating so-called sirtfoods, a group of “wonderfoods” that include nutrient-rich options like kale, cocoa, strawberries, and coffee.
The idea is that certain foods activate sirtuins in your body (a type of protein found in plants) that allegedly boast a slew of benefits, like protecting cells from inflammation, kick-starting your metabolism, reversing aging, and activating your “skinny gene pathways,” according to the diet’s website.
Some research, like one 2018 review published in the journal Circulation Research, suggests that sirtuins may help prevent age-related decline (in mice, at least). Another review published in Frontiers in Endocrinology concludes that sirtuins may help prevent insulin resistance and chronic inflammation. But again, this was based on animal studies.
While sirtuins are considered healthy, there’s still a lot people don’t know about them. “The research on sirtuins is promising but more is definitely needed, especially on humans, to determine if any of the claims can be conclusively substantiated,” says Keri Gans, M.S., R.D.N., C.D.N., a nutrition consultant based in New York City.
What are “Sirtfoods”?
The Sirtfood Diet only mentions a few sirtfoods on its website and blog, but these options make the cut, all of which are nutrient-dense and healthy to eat regularly:
oily fish, like salmon, trout, and mackerel
What does the Sirtfood Diet meal plan look like?
The diet is divided into two phases, and followers are encouraged to do them whenever they feel like they need a weight loss boost.
This lasts for seven days and it’s also split up. During the first three days, you’ll have three sirtfood green juices and one regular meal that’s rich in sirtfoods—for a total of 1,000 calories a day. On days four through seven, you’ll have two green juices and two daily meals for a total of 1,500 calories a day.
This is a 14-day “maintenance phase” that’s designed to help you lose weight at a steady pace. During this phase, you’ll eat three balanced meals that are rich in sirtfoods, along with one green juice. It’s unclear whether this phase has a set calorie intake.
The juices usually consist of matcha, the herb lovage, and buckwheat. As for the meals, recipes include soy yogurt with berries, walnuts, and dark chocolate, an omelette with bacon, red chicory, and parsley, a pita with turkey, cheese, and hummus, and stir-fried prawns with kale and buckwheat noodles.
Once you’re done with the phases, you’re supposed to look at the Sirtfood Diet as a way of life. “You are encouraged, once you’ve completed the first three weeks, to continue eating a diet rich in sirtfoods and to continue drinking your daily green juice,” the diet’s website says.
The official site also recommends that you stop working out or cutting back on your usual routine during the first phase, since you’re not taking in many calories. But, once the diet becomes a way of life for you, it encourages exercising (and eating protein an hour after you work out to repair muscles and reduce soreness).
Can the Sirtfood Diet help you lose weight?
Yes, you’ll probably lose weight on the diet. “Most people definitely will lose weight during phase one, since they are probably consuming way fewer calories than they usually do,” says Gans. While a lot of this may be water weight, it’s possible to lose actual body fat too.
But that doesn’t mean it’s healthy. “It seems gimmicky,” says Jessica Cording, M.S., R.D., author of The Little Book of Game-Changers. “Any diet where there’s a cycle of super restrictive eating and maintenance isn’t really sustainable.”
What are the downsides of the Sirtfood Diet?
First, phase one of the diet is “a bit extreme,” says Scott Keatley, R.D., of Keatley Medical Nutrition Therapy. “A 1,000 calorie-diet is below what is used in almost all human research studies because it is deemed unsafe.” People can lose fluid and lean muscle mass while having a caloric intake this low, and it can mess with your metabolism, he says.
Restricting your caloric intake this heavily can only be “OK” for a few days, but it’s really not ideal, says weight loss expert Michael Russo, M.D., a bariatric surgeon at MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA. “It’s really important to pay attention to what types of calories you’re getting in,” he says. “Getting adequate protein is crucial, because they’re the building blocks of the body.”
The juicing part isn’t exactly a hit with experts, either. “I’m not a huge fan of making juice out of foods, especially when we’re talking weight loss, as the blender is doing a lot of the work your body should be doing,” Keatley says. Green juice is often much lower in gut-filling fiber than you’d get if you just ate the ingredients themselves, Cording says, which is bound to leave you hungry.
The diet is also lacking an educational component of helping people better understand what foods are good for their health, and how to develop healthy eating patterns due to how restrictive it is, Cording adds. Finally, there are really no guidelines beyond the two phases—unless you buy the Sirtfood Diet books.
Bottom line: If you do want to try the Sirtfood Diet, be realistic about your expectations.
You should also speak with a dietitian or doctor before your dramatically reduce your calorie intake and glug a ton of juice in the name of weight loss.
Ultimately, the Sirtfood Diet isn’t backed by significant research, so you’re likely better off following a healthy diet you know you can stick to consistently (or a more scientifically-proven option, like the Mediterranean diet), exercising regularly, and getting plenty of sleep.
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