Strategies To Lose Weight Fast

A friend of mine just had a baby and needs to lose 70 pounds…she asked me for advice since I once lost 30 pounds. However, I did this over a long period of time. She wants to lose the weight fast, and so far, she has been losing 4 pounds a week. Is this okay for her? If not, what are some tips I could give her on losing weight properly?

I’d like to lose 100 pounds before January 1, but I’ve heard that if you lose more than 2 pounds a week you can lose muscle mass. If I exercise at the same time, will I still have ill effects from losing 3 pounds a week?