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Popularized this January through The Sirtfood Diet book and with fans such as Adele and Pippa Middleton, you might be wondering: What on earth is Sirtfood?

The Sirtfood Diet is based on the idea of eating foods rich in sirtuins, proteins in your body that regulate your metabolism and supposedly imitate the effects of exercise and fasting. The Sirtfood Diet is a three-week plan that prescribes green juices and sirtfoods such as kale, strawberries, celery, green tea, onions, and walnuts. Sticking to a strict sirtfoods diet supposedly activates our “skinny genes” to help us lose weight fast. And big bonus: You can have chocolate and wine on the Sirtfood Diet.

But you know what they say: If it sounds too good to be true, it probably is. Before your body goals tempt you to try this diet trend, here are five truths you need to know about the Sirtfood Diet from medical experts. 

01. It Lacks Conclusive (Human) Research

The regimen sure sounds intriguing, but the only evidence connecting weight loss and sirtfoods comes from studies involving animals—not humans. Dr. Caroline Apovian, Director of the Nutrition and Weight Management Center at the Boston Medical Center, tells Verily, “The research on sirtuins is promising, but incomplete. More studies need to be conducted on the properties of these foods for weight loss.”

02. It Dangerously Restricts Your Calorie Intake

The extreme calorie restriction in the first week of the program is basically akin to starvation. The daily caloric intake for the first three days of the diet is limited to 1,000 calories coming from green juices and one meal of sirtfoods. It then increases to 1,500 calories for the rest of the week. The remaining two weeks of the diet focus on keeping off the lost weight through three sirtfood meals per day and a steady intake of green juices.

Eating this amount of any type of food for a week will make you lose weight—that’s no secret. Founder of FoodTherapyMD Dr. Stacy Mitchell Doyle, M.D., explained to Verily, “A restriction like this will obviously result in weight loss but may be too low [in calories or variety] for many to maintain, especially if you are physically active and want to avoid binging or food cravings.”

03. It Promises Unsafe Weight Loss

During the first week, most people who follow the Sirtfood Diet lose an average of seven pounds. This rapid weight loss is way too fast. Toby Amidor, M.S., R.D. and author of The Healthy Meal Prep Cookbook tells Verily, “The promised rate of weight loss in the first week is rather quick and not in line with the National Institute of Health safe weight loss guidelines of one to two pounds per week.”

04. It Cuts Out Necessary Nutrients

While sirtfoods are nutritious and should supplement a balanced diet, they don’t have all the important nutrients you need from banned foods like dairy, healthy fats, whole grains, and most proteins. Dr. Apovian adds, “Following any diet that does not include a healthy amount of protein will result in muscle loss and a slower metabolism. By sticking only to the approved foods, dieters are at risk of missing out on key nutrients.”

05. The Results Won’t Last Forever

The true test of any diet is its lasting power. Experts argue that sirtfoods aren’t actually responsible for the weight you lose during this diet; the extreme calorie restriction causes it. Dr. Apovian notes that after the first week, “You'll feel slimmer, but it's probably water weight. You can't lose fat in that short an amount of time."

The Sirtfood Diet has little supporting research to date and relies on unhealthy levels of calorie and nutrient restriction. While celebs tend to tempt us into extreme lifestyle experiments, it's important to remember that they often follow diets with the support of trainers, nutritionists, chefs, personal trainers, and more. The best way to achieve a healthy weight is through sustainable lifestyle-based eating and exercise—not speedy fasts.

Photo Credit: Wikimedia Commons