Would you do an extreme (not to extreme) kind of diet to get...

Would you do an extreme (not to extreme) kind of diet to get the first pounds of and once the loss had kicked in, and the process started, switch to a healthy eating plan?

No, your body had lost lots of weight in a short period, it's in stress. When you loosen up your diet it may start "storing" again because of this stress. It's always better to have a moderate diet plan. If you have a lot of weight to lose it will get easily off you in the beginning anyway.