"Just cycling will not make you lose weight.
Just running will not make you lose weight."
I would argue with you on this issue. Loosing weight is about creating a deficit. If you eat the same and burn off 700 a day cycling or running then you have created a deficit but maybe not enough to loose weight. If you were eating a 700 calorie surplus then you are at even.
Bottom line - Create a health negative deficit, preferably through a combination of exercise and diet but not manditory to have both.
Anyway good post.