Dark shadow. You are a very speciall case. Maybe you can't eat fat. But still, fat is a good thing to eat. There are two kinds of fat wich I don't know the english for. We call it "mättat fett" and "omättat fett". Just a clue if someone happens to know

Fat is what gives us energy. So if you avoid fat you will get tired quick.
Back in time, before the refrigirators time, We had very fat meat, And we salted it with much salt so it wouldn't get bad. That was our priory one food. Meat or fish. Was there so bad for uss to eat it then? no! Is it today? no! What has changed? The carb has changed. We eat much more carb today. What more? All the chemicals, aroms and so on...
We have some different ways to se balanced and healthy food here. But we have one thing in common. No processed food!
So I beleive that the best tip for a balanced food is just that. Avoid processed food. That should save years of your lives just that
Then if you want to actually follow a diet then go ahead and pick one you are comfortible with. for me, it will be LCHF.
BTW: Fruit are bad!!! It contains acids that is not good for your body. And it contains much Carb for the the ones who dont eat that. Green vegitables is very good!