@schratze I think if a qualified doctor advises anyone to lose weight that is advice based on medical science, so unless that person is qualified to assess then their opinion can be questioned.

IIRC Body mass index, a ratio of weight to height thing, was problematic for the Royal Marines in the UK, it didn't take in to account Muscle also weighs something so what they lacked in body fat, then had in Muscles, so their actual BMI said they were obese despite actually being very healthy.

As people have said before on here, follow the science. Your GP / doctor also knows you so can allow for existing medical conditions.