Why did Islam not guide us to reduce the consumption of red meat, the abundance of which causes high cholesterol, leading to heart attacks and blocked arteries, even though the Quran only forbade pork?

The Quran is a book of guidance and legislation, not a book of medicine or astronomy. The Quran mentions some prohibited foods and general rules, while the Prophet's Sunnah (definition) clarifies their details. Islam prohibits impure things (al-khaba'ith) and permits good things (at-tayyibat). The prohibition includes everything that harms a person, even if it was originally permissible, and this varies depending on individuals and countries.