[misterspaceman]

Agreed! And to your point, I tried to include a couple of activities with a low barrier of entry in my above post. You could argue that bodyweight-only YouTube workouts have an even lower barrier of entry than running (you don't even need shoes!).

Also, a small nitpick: if someone is starting from zero, I'd argue "effectiveness" probably shouldn't be the goal...it should be finding an activity the person loves and wants to keep doing. From my own experience: For years I hated fitness and avoided it at all costs...until I found a gym with group fitness classes that I fell in love with. From there, losing weight was easy because I was just doing something I loved.