How to lower my bad cholesterol levels most quickly?

No meat: Go on a vegetarian diet. Achieve and maintain optimal weight. Don't smoke. Exercise 1 hour daily. Beyond that, only statins are really effective.

Follow the following: Exercise most days of the week (aerobic work), eat fruits and vegetables liberally, limit saturated fats, increase fish and fish oil intake, have fiber with each meal, keep your weight in check, don't smoke at all or drink excessively (one or two drinks weekly). The lower the better on LDL and the higher the better on HDL. You have to eat, just keep it healthy and you'll be fine.