I'm pretty sure we know this isn't true at all. Diet is the greatest contributing factor to weight gain or loss. Exercise will make you healthier. In your ex

I'm pretty sure we know this isn't true at all. Diet is the greatest contributing factor to weight gain or loss. Exercise will make you healthier. In your example, cardio (e.g. high-intensity interval training), will give you a stronger cardiovascular system, which will likely make you "feel better" (less strained, more comfortable) when moving around in the world. And strength training (e.g. resistance training) will make you stronger and more comfortable when trying to lift things or even yourself.