How come God didn't include sugar and obesity in the word of wisdom?

It seem odd that our heavenly father would have commanded us not to drink tea which has now been proven to have many health benefits, while at the same time not including white flour, sugar, etc. as part of the Word of wisdom since we know today that those substances pose a huge health risk to both society and church members as relating to Diabetes, obesity, tooth decay, etc. Why does the church give a temple reccomend to a member who is grossly overweight and eats excessive starch every day while denying the temple to someone who cares for their body, exercises, but may confess to sipping green tea occasionally?