The sirtfood diet is a new creation of a group of celebrity nutritionists in the UK. Its main premise is that a carefully designed ratio involving calorie restrictions and several healthy products produces miraculous weight loss. However, the evidence-based foundation and sustainability of the diet are questionable, meaning it is likely a fad rather than a responsible dietary choice.
There is little evidence to confirm the efficiency of the sirtfood diet. The only study its creators refer to was not published anywhere except for their own diet book. Even then, it does not offer any revolutionary insights, as it merely demonstrates that limiting the calorie intake and combining it with exercise leads to weight loss in the first weeks. Still, this is mostly water weight lost with the glycogen reserves – an effect known long before the sirtfood diet. If a person continues restricting calorie intake afterward, their organism will eventually break down the muscles, and if the calorie intake increases, people are likely to gain the weight back just as easily.
Another downside to the sirtfood diet is the lack of sustainability. The products its creators promote are undoubtedly healthy, but insufficient to cover all needs of the organism. In particular, the restriction of 1,000 calories per day is excessively harsh. Additionally, the diet likely lacks in proteins, minerals, and vitamins.
To summarize, the sirtfood diet is based on healthy products but assigns nonexistent qualities to them. The weight loss from the diet is mostly water weight likely to be gained again. The limited scope of healthy foods promoted by the creators of the diet is not sufficient to satisfy the organism over prolonged periods. Hence, the emergence of sirtfood diet looks more like a marketing move rather than a scientifically supported and sustainable nutritional choice.