I really love lemons. They just have them. I have been eating for a year now.
Have I lost weight this year?
Because I ate lemons?
No, because I went on a diet and went to the fitness room)
Once I had to perform at student competitions in kettlebell lifting and in order to lose weight and keep within the weight category, the coach advised me to eat lemon. I did so and the weight dropped. I think it's not my experience that's important here, but the fact that the coach was a person who knew a lot in his field.
It helps, but only if you follow a hypocaloric diet, because citric acid is one of the substrates of the tricarboxylic acid cycle, and the introduction of this compound in an additional amount will accelerate the course of biological oxidation processes, increase the consumption of glucose and glycogen and the catabolism of adipose tissue through the processing of fat into glucose (if to describe only the key points, in reality everything is more complicated). But the basis is still a low-calorie diet and adequate physical activity.
Calorie deficit helps to lose weight, not lemon / pineapple / grapefruit and all kinds of dietary supplements. Lemon and other citrus fruits, as well as fruits, are nothing more than an addition to the diet and do not contribute to weight loss in any way. For example, what is the use of lemon if you ate a kilo of cake before?