Learn which running form cues research supports, why heel striking is fine, how to film a quick self-check and how to change one habit at a time without overdoing it.
Where your knee hurts points to the likely cause. Learn the warning signs, a pain-guided way to keep running, and the training and strength changes that help.
Running can help reduce body fat, but a special heart-rate zone or an empty stomach isn't the deciding factor. Start with training you can repeat and fuel well.