Alessandra. Welcome to Medifast red, the best answer to the average weight loss is, it varies. Guys seem to lose more per week and faster than women. Great for us guys, not so great for the gals. Most guys will lose 5-10 pounds per week in the first two or three weeks.lessandra. Welcome to Medifast red, the best answer to the average weight loss is, it varies. Guys seem to lose more per week and faster than women. Great for us guys, not so great for the gals. Most guys will lose 5-10 pounds per week in the first two or three weeks.