Your medical will almost certainly be referred to the Medical Assessors. Their job is to understand a person's state of health and to declare it acceptable or not - the INZ CO can't finalize work on the visa application till they have received clearance from the MA.
You've found the other thread. You know therefore that they are now saying the BMI should be under 30 for it to count has normal, hence the certainty of referral. The MA would probably ask (they have the right to REQUIRE whatever they want to, multiple times if need be) to see a doctor's report on your health, any treatment, any recent history of slimming, etc.. You can pre-empt this by going to your own doctor and asking for such a report, then sending it to INZ, mentioning your eMedical number and all the details. There is always a queue (6 - 8 weeks recently) for medicals to be seen by an MA, so, with luck, the report will catch up with your file while it is waiting, then when it gets to the MA, whatever s/he wants to know will be right there, ready.