Exercise is important, but the befits taper off rapidly. A little exercise goes a long way, but more isn't incrementally better.

People need to stop referring to such a goal as weight loss, as what they are really talking about is fat loss.

Pro tip; if you want to lose weight most rapidly then don't eat! That works for 100% of people, as we are highly adapted to survive short periods of famine. What we are not adapted for is to have a limitless supply of calorie rich food which requires no effort to obtain; hence the obesity crisis!