If Adam hadn't have eaten the forbidden fruit, then disease and death would not exist. Stop blaming God.
Stranger makes a good point in that this has little to do with his comment that you alluded to.
However, as you seem to have brought up the story of the 'forbidden fruit' as being in any sense believable then consider a few other utterances from your OT.
God's love entails destroying all the first born in Egypt (psalm 136). A real family man your God is!
All witches should be killed(Ex 22:18). Really shows his expansive humanity that does!
God wants to destroy all Jews because they don't believe in Him. Luckily He is talked out of His vindictive attitude by Moses.(Num 14: 1-36) Phew!
A stubborn and rebellious son should be stoned to death.(Deut 21:18) Good old family values again!
God believes that if a person is gathering sticks on the Sabbath he should be stoned to death. Pernickity, isn't He, your God?
He didn't want imperfect people to be around Him, people such as the blind, the lame, dwarves, hunchbacks, those with mutilated faces etc.(Lev 21:17). Not exactly all encompassing, is He?
When God lived in a box(The Ark of the Covenant) He could get quite stroppy and irritable at times. When some people looked in His box, He reacted by killing 50,000 of them.(1 Sam 6:19). I'd call that a little over the top, wouldn't you?
So, let me make it clear. If these stories, including the preposterous Adam and Eve story, are in any sense literally true then all we have is a monster. I don't blame your God, because I have no belief in Him, but, if He did really exist then he is ultimately responsible for all that He has created, and that includes human beings and diseases.