The bigger question is, what does it matter? If your weight over time is staying the same or decreasing, whatever it is you're trying to do, variations in one day don't matter. There are so many factors that go into short-term variations in nutrient levels, weight, etc. that focusing on such short-term variations sounds more like an eating disorder or an obsession than a focus on healthier living. Which is also raised by the fact you're going through your day without eating or drinking. So I guess I'd ask, what are you trying to accomplish, how are you trying to accomplish it, is it working for what you want, and is it healthy for you long-term?