In order to lose weight while running, is it best to sprint then walk in intervals?

Intensity N duration. The more intensive the work-out/running and longer time will burn more calories. Alternating between jog/walk/sprint provide good balance of cardiovascular and wt management benefits. Start out easy and increase overtime. Chose methods that fit your lifestyle/work/family--living healthy is a life-time commitment. Eat well/sleep well and exercise regularly. See doc regularly too. Good luck.