Generally to lose 1 to 2 pounds a week, you need to burn 500 to 1,000 calories more than you consume each day.
(Hopefully that answered your question…)
The fat didn't leave his body. Your friend less consumption of fat forced your body to use the energy from the already consumed fat in your body, which in turns lowers the amount of fat visible to the eye. There's still fat in your friends body just not as much. A little fat is healthy for your body. <span />
