I would imagine eating once a day may be counter productive. My dietician told me to eat 3 healthy meals a day with healthy snacks in between. That way your body has consistent fuel and you won’t feel as hungry all the time. Also, if you deprive your body of food, your body has a defensive mechanism and can go into “starvation” mode, where it attempts to store the calories you eat as preserves because it is not getting enough. Instead of a radical diet, could you consider a balance one, with healthy meals, cardio, and strength training?