I have lost 1 kg per week during almost a year, with a considerable health improvement at the end and no negative effects, except obviously, the hunger.
At the time I have studied a lot the existing medical literature, and this was the recommended rate, so I have adjusted the diet so that the weight loss per day would oscillate around 140 g per day.
The weight must be measured every day in the same physiological conditions, i.e. in the same order relationship with respect to the various activities that modify the weight, like eating, drinking or eliminating their products.
A good moment would be in the morning, immediately after waking up and relieving yourself.
If one would eat in the evenings wildly varying amounts of food, then the weight in the morning could be affected by a noise due to variable amounts of food that is not completely digested yet. However that would not happen when one is eating a calorie-restricted diet for losing weight, when one would have to eat about the same minimal amount of food every day, which would be quickly digested.
While I was losing weight, I could see very well every day its evolution to the grams, and the effect of any change in the diet. Sometimes I succumbed to the temptation of eating like before starting to lose weight, and after such days I gained weight in a day almost as much as I was losing in a week, which increased the time until reaching the target weight.