Why should we use "estar" over "ser" for being old or fat?

Question

I can understand why we would use estar for temporary states. But there are conditions that people have that are not temporary, such as being old (or for some people, being fat).> ¡qué gordo está! ¡pobre abuelo! está viejo. ¡todo está tan caro!These subjects aren't going to change: people won't get younger or thinner, and things aren't going to get cheaper.Why do we use "estar" for these and not "ser"?

Answer 1

The verb "estar" has a temporary connotation and "ser" has more permanent connotation or nuance.

So when you say "Maria es gorda" you are meaning she is always fat. It is a characteristic you consider permanent (even though it is changeable)

But when you say "Maria esta gorda" it refers to a temporary condition. You mean she is not usually fat, but she looks fat now.