This study examines student workload after a change in teaching style from lecture to Problem Based Learning and Cooperative Learning, and its relationship with student outcomes. Results show that the change clearly overloads students if it is not adequately planned and monitored. Marks, drop-outs and attendance were markedly better with the new instruction method, but also with a higher workload. The main conclusion is that calculating student workload in terms of hours is very important, but especially when implementing a change in teaching style. (Contains 2 figures.)