Hi @MezDiaz - sorry to see you here - it is a road we've all travelled. If you have any questions that may help you navigate the minefield - don't hesitate to ask here & someone will give honest answers.
How much do you weigh? Are you trying to lose weight or just eat healthily?
When I was diagnosed in Jan this year, well meaning friends said I should eat this, not eat that, don't drink this - drink THIS ...... and I figured that changing my diet at that point in time was not going to change my situation at ALL ...... so said thanks & ignored it all!! LOL
If you eat healthily - you should be OK. If you want to lose a bit of weight - just cut down on the carbs - 1/2 a potato instead of 1 or 2, don't have too many sweet drinks, have protein with every meal (it is more 'satisfying' and you feel less hungry.) Regular small meals are better than 3 whopper meals.
The 'high fat' I believe relates to grass fed meat fat .... it is more 'natural' than grain fed meat fat. It also relates to nuts as well - like pistachio & cashews .....
If you are about to have surgery and treatment - you need to be well ..... so maybe don't do too many drastic changes just now
All the best for your treatment - we'll be thinking of you xx