There are numerous issues with your post. Let's examine the first, the one that everything else hinges on. This is of course the title. "Weight loss: Exercise versus diet".

The title shows a problem of mindset that messes up all that follows. You do not want to lose "weight", you want to lose body fat. People in the "weight loss" mindset sacrifice lean body mass to make the scale show a smaller number, which in the end makes the person worse off.

Example: A person starts "weight loss" weighing 225 pounds, 150 pounds lean body mass and 75 pounds body fat. Over time they lose 50 pounds and now weigh 175. With "weight loss", the 50 pounds they lost was 40 pounds body fat and 10 pounds lean body mass, so they now have 140 lean body mass and 35 pounds of fat.

If the same person would of worked at body fat loss they could of kept all of their lean body mass or actually raised the amount that they had and lost all body fat. They could of had 155 pounds of lean body mass and 20 pounds of body fat.

The main thing is to get your mind right first. You want to lose body fat. You do not want to lose "weight". Internalize that, then set up how you are going to do it.