Well I gained about 20 kg on chemo so lucky you with only 8 kg to go.
I went on optifast to get all that weight off prior having my boob recon surgery changeover. But started to regain weight once back working full time, being exhausted and not prepping enough healthy meals during day.
I've returned to weight watchers. I just do online. They recently overhalled their program and it is really quite simple to follow. And my belief is it helps you make the lifestyle changes long term.
I believe in some areas weight watchers do fresh boxes...hich include all ingredients and recipes for meals. I've never used them as not available in my area but others I know really liked them.
I do know of people who have had great succes with light and easy.
Then there is always My fitness pal which has a calorie count app which is good but totally biring to track everything. ..but it is a great tool. I continue to gain weight on chemo though even doing this ...friggin steroids.
I do have to be stricter to lose weight than pre letrozole. But...also I'm not yet doing as much exercise as I used to so I don't need as much food.
What I have found...since overhauling my diet, getting better sleep and moving more I have more energy and the weight is steadily coming off.
And yes...aramatose inhibitors such as letrozole are for post menopause women. We apparently make estrogen in our subcutaneous fat so the letrozole blocks our bodies ability to use it.
Studies have shown women who stay within healthy body weight and have regular exercise seem to have less issues after breast cancer. (But no guarantees by any means)
https://breast-cancer.canceraustralia.gov.au/treatment/hormonal-therapies/types-hormonal-therapy