What Is the Sirtfood Diet? Here’s a Dietitian’s Review

Carrie Gabriel, MS, RDN, looks at the trending sirtfood diet for weight loss and reviews it from a nutritional standpoint. When English pop singer/songwriter Adele premiered a shockingly slimmer figure in spring 2020, a diet many of us had never heard of before started to gain hype. Enter: the sirtfood diet. Here’s what you need to know about diet behind Adele’s weight loss.

What is the Sirtfood diet?

First, let’s take a look at sirtfoods. Sirtfoods are high in sirtuins, a group of proteins that regulates several functions in the body. This type of protein has been shown to regulate metabolism, increase muscle mass, and help burn fat in a variety of studies done on fruit flies and mice. Supposedly, these sirtuins shift weight quickly without radical dieting by inducing pathways typical of other weight loss methods. Certain foods contain chemicals called polyphenols that put mild stress on our cells, activating supposed “skinny genes” that mimic the effects of fasting and exercise. Foods rich in polyphenols trigger these sirtuin pathways. The sirtfood diet purportedly promotes weight loss without sacrificing muscle, all the while maintaining optimal health. Finally, while the diet plan encourages exercise, it’s not a primary focus.

Sirtfood Diet Foods

The standout ingredients in the sirtfood diet green juice are matcha, buckwheat, and lovage. Lovage is a celery-flavored sea parsley that may be difficult to find. However, you can find seeds and grow it in a pot on your windowsill. (From a dietary perspective, it sounds like a random trio of ingredients.) Undoubtedly, one of the major appeals is that the best sirtfood diet foods supposedly include red wine and chocolate. Other staples include citrus fruits, blueberries, and kale. Additionally, sirtfood snacks include walnuts and celery with hummus. As for sirtfood diet meals, sample dishes include the likes of shrimp stir-fry with buckwheat noodles, chicken curry with brown rice, and a kale omelet.

How to Follow It

Phase One

The first phase lasts three days and restricts calories to 1,000 per day from three green juices and one sirtfood diet meal.

Phase two

The second phase lasts four days and raises the daily allotment to 1,500 calories per day with two green juices and two sirtfood diet meals.

Maintenance

Following the two phases, you should follow a two-week maintenance plan. It doesn’t focus on calories, but rather on sensible portions, well-balanced meals, and filling up primarily on sirtfoods. The 14-day maintenance plan features three meals, one green juice, and one or two sirtfood snacks. For greater weight loss results, you can also repeat the full process as desired.

Does the Sirtfood Diet Work?

First, it should be pointed out that most of the diet is based on caloric restriction. As for what we really know about this diet? Scientifically speaking, very little. Sirtuins are indeed involved in a wide range of cellular processes including metabolism, and circadian rhythm. Sirtuins contribute to the regulation of fat and glucose metabolism in response to changes in energy levels. They might also play a part in the impact of calorie restriction to improve signs of aging. The sirtfood diet will appear to work for some people—but scientific proof of any diet’s success is a different matter. Complicating things further is that most of the current research tested sirtfood diet results on mice, flies, or in small sample groups. (While the authors of The Sirtfood Diet book reported an average of seven pounds of weight loss in seven days across 39 participants, these results were self-reported and not published elsewhere.) Of course, an ideal study investigating the effectiveness of a diet on weight loss (or any other outcome) would require a larger sample size of people who represent the population of interest. Then, researchers would monitor the outcomes over an adequate period of time with strict control over the variables. These variables include behaviors that may affect the outcomes of interest, such as smoking or exercise.

A Dietitian’s Review of the Sirtfood Diet

Simply put, the sirtfood diet is incredibly strict and its effectiveness hasn’t been adequately proven through existing research. A mere 1,000 calories a day is too restrictive. Even 1,500 calories a day is pretty insufficient for an active person. This level of caloric restriction makes the sirtfood diet harder to stick to, and can backfire into bingeing. Furthermore, drinking three green juices a day in phase one doesn’t seem sustainable. While fresh juices can contain vitamins and minerals, they’re stripped of fiber, so they aren’t very filling. Also, the ingredients specific to the sirtfood diet juices don’t include healthy fats. As a registered dietitian, I wouldn’t recommend this diet for weight loss or health benefits. A person is much better off developing a lifestyle of eating a variety of whole foods in the portions that suit their individual needs.