This is no problem. The 13-day course of treatment will not be ineffective if you fail to persist at one day. Provided you don’t eat a lot of snacks every day. I didn't strictly follow the recipe every day, and I substituted some ingredients that I couldn't buy with others. The final effect was very obvious, and I lost about eight pounds. But I remind you that it is easy to rebound once you return to normal eating, so the process of returning to eating should be slower.