The new trending diet lets you eat chocolate and red wine and has celebrity followers like Adele. But is it too good to be true?
"Sirtfood" sounds like something developed by aliens, brought to earth for human consumption in the hopes of gaining mind control and world domination. In actuality, sirtfoods are simply foods high in sirtuins. Uh, come again? Sirtuins are a type of protein that studies on fruit flies and mice have shown regulate metabolism, increase muscle mass, and burn fat.
The Sirtfood Diet book was first published in the U.K. in 2016. But the U.S. release of the book, coming this March, has sparked more curiosity about the plan. The diet began getting hype when Adele premiered her slimmer figure at the Billboard Music Awards last May. Her trainer, Pete Geracimo, is a huge fan of the diet and says the singer lost 30 pounds from following a sirtfood diet. (Here, Adele gets real about getting healthy.)
According to the book, this plan can help you burn fat and boost your energy, priming your body for long-term weight-loss success and a longer, healthier, disease-free life. All that while drinking red wine. Sounds like pretty much the perfect diet, right? Well, before you burn through your savings stocking up on sirtuins-filled ingredients, read the pros and cons.
How does it work?
At its core, the key to losing weight is pretty simple: Create a calorie deficit either by increasing your calorie burn through workouts or decreasing your caloric intake. But what if you could skip the dieting and instead activate a "skinny gene" without the need for intense calorie restriction? This is the premise of The Sirtfood Diet, written by nutrition experts Aidan Goggins and Glen Matten. The way to do it, they argue, is sirtfoods.
Sirtfoods are rich in nutrients that activate a so-called "skinny gene" called sirtuin. According to Goggins and Matten, the "skinny gene" is activated when a shortage of energy is created after you restrict calories. Sirtuins became interesting to the nutrition world in 2003 when researchers discovered that resveratrol, a compound found in red wine, had the same effect on life span as calorie restriction but it was achieved without reducing intake. (Find out the definitive truth about wine and its health benefits.)
In the 2015 pilot study (conducted by Goggins and Matten) testing the effectiveness of sirtuins, the 39 participants lost an average of seven pounds in seven days. Those results sound impressive, but it's important to realize this is a small sample size studied over a short time. Weight-loss experts also have their doubts about the lofty promises. "The claims made are very speculative and extrapolate from studies which were mostly focused on simple organisms (like yeast) at the cellular level. What happens at the cellular level does not necessarily translate to what happens in the human body at the macro level," says Adrienne Youdim, M.D., the director of the Center for Weight Loss and Nutrition in Beverly Hills, CA. (Here, check out the best and worst diets to follow this year.)
What foods are high in sirtuins?
The book contains a list of the top 20 foods that are high in sirtuins, which sounds more like a trending food list than a new, sophisticated diet. Examples include: arugula, chilies, coffee, green tea, Medjool dates, red wine, turmeric, walnuts, and the health-conscious favorite—kale. Dr. Youdim notes that while the foods being promoted are healthy, they won't necessarily promote weight loss on their own.
What does the diet entail?
The diet is executed in two phases. Phase one lasts three days and restricts calories to 1,000 per day, consisting of three green juices and one sirtfood-approved meal. Phase two lasts four days and raises the daily allotment to 1,500 calories per day with two green juices and two meals.
After these phases, there is a maintenance plan that isn't focused on calories but rather on sensible portions, well-balanced meals, and filling up on primarily sirtfoods. The 14-day maintenance plan features three meals, one green juice, and one or two sirtfood bite snacks. Followers are also encouraged to complete 30 minutes of activity five days a week—per government recommendations—but it isn't the main focus of the plan.
What are the benefits?
You will lose weight if you follow this diet closely. "Whether you're eating 1,000 calories of tacos, 1,000 calories of kale, or 1,000 calories of snickerdoodles, you will lose weight at 1,000 calories!" says Dr. Youdim. But she also points out that you can have success with a more reasonable calorie restriction. The typical daily caloric intake of someone not on a diet is 2,000 to 2,200, so reducing to 1,500 is still restricting and would be an effective weight-loss strategy for most, she says.
Are there any precautions?
This plan is strict with little wiggle room or substitutions, and weight loss can only be maintained if the low caloric intake is also maintained, making it difficult to adhere to long-term. That means any weight you lost in the first seven days is likely to be gained back after you finish, says Dr. Youdin. Her main concern? "Limiting protein intake with juices will result in a loss of muscle mass. Losing muscle is synonymous with dropping your metabolic rate or 'metabolism,' making weight maintenance more difficult," she says.
Overall, Dr. Youdim would not recommend this diet. There are other ways that you can reduce calorie intake without being so restrictive in the foods that you eat. With that being said, the diet is not necessarily "unhealthy" so she wouldn't necessarily caution against it if a patient found success.
If you do follow this plan, be sure to eat plenty of protein and vary the foods you eat to prevent vitamin deficiencies. Our take? The diet is incredibly strict and its effectiveness has not been adequately proven. You're much better off developing a lifestyle of eating a variety of whole foods in the proportions that suit your individual needs.