Generally, people are heavier in the morning when they first wake up. They urinate. Then, they take a water pill in the morning. Two hours later, they weigh themselves, and discover they weigh less.
When you should weigh yourself
It doesn’t matter when you weigh yourself, as long as you consistently follow the same routine. This means, do it the same time, using the same scale, wearing similar clothing, and after you have used the bath room. You should be looking at the change in your weight, instead of the actual number of pounds.
I don’t recommend weighing yourself daily. Instead, step on the scales once a week or even less frequently. Your weight fluctuates from day-to-day. Weighing yourself every day will lead to disappointment and a possible disruption in your diet if the number on the scale is higher than the previous day.
Weigh yourself in the morning after you first use the bathroom, and before you eat or drink. Always follow this routine, whether or not you decide to take a water pill.