When British superstar Adele was photographed looking considerably lighter, the internet was desperate to know her secret. Rumour has it that she followed the Sirtfood diet.
Stemming from a recipe book of the same name, it is a diet based on calorie restriction and a diet high in sirtuins. The website dedicated to sirtfoods states that these are a group of proteins found in plant foods such as strawberries, kale, tumeric and even red wine. These sirtuins are said to switch on your “skinny gene” to boost weight loss and protect against disease. But there is a catch. In the first week, you have to drink green juice three times a day and really cut back on your calories – 1,000 calories for 3 consecutive days in the first week and 1,500 calories in the second. After completing these phases you eat a healthy diet, regularly incorporating sirtfoods.
Sirtfoods themselves are healthy as most of them are fruit, vegetables, herbs, and spices. But there is no evidence to just focus on sirtfoods, rather, focus on incorporating a variety of healthy foods in your diet as this will provide you with a variety of vitamins, minerals and antioxidants. Another reason not to focus just on sirtfoods is that some e.g. lovage, matcha green tea not only have interesting names but come with a hefty price tag. Not to mention that you’ll have to buy an expensive juicer to make all that green juice as a blender won’t do.
But what tells us it’s not a sustainable diet is the drastic calorie restriction in the initial phases of the diet. The weight loss observed on this diet is unlikely due to the magical properties of sirtfoods, rather it is due to eating much less than you are supposed to. You are bound to lose weight in this phase of the diet, due to the heavy calorie restriction. But fat loss takes time, so most of the weight loss in the initial phases is water weight, and once that phase is over the weight is likely to come back on. The website states that this diet helps you “quickly shift weight” which is a definite red flag especially with advice to repeat this calorie restriction if you feel like you are getting off track – this is not recommended. It promotes yo-yo dieting and this can be harmful in the long run.
So incorporating sirtfoods in your diet is not going to hurt, but the evidence that they are any more special than other fruit and vegetables is not proven. What we do not recommend is going on diets that promote rapid weight loss through drastic calorie restriction as they are not sustainable long term.
Last modified: January 19, 2022