Starving yourself will make you lose weight but will also cause bad health. The best diet to lose weight is to drink lots of water and eat fruit. +exercise
Well the hormone would be one thing. I'd say because it strengthens our heart muscles and trains our breathing pattern to be more effective. These would lead to more efficient transportation of blood and hence oxygen to our whole body including our brain. Our brain becomes more alert, and our body more energetic.
A. U.S. government website is most likely to contain information based upon empirical evidence.