My mother eats very small meals but has become very "puffy" lately, her stomach is very swollen, her ankles are puffy, her thighs, top of her arms, even her feet look swollen, not tightly stretched swollen but puffy swollen. She is of the generation before the NHS so is reluctant to visit the doctor over such a vague thing but thinks she has read somewhere that this sort of puffiness is connected with the kidneys.
She may well be correct.
There are other alternatives, but she does not to see her GP as this state of affairs that you mention does need investigation.
That is all one can say at the moment.