"Starvation Mode" As explained by WeightWatchers.

grinch031

They are wrong about the end part - research shows that a 150 lbs person who used to weigh 200 has a lower metabolism than a 150 lbs person who has always weight 150 lbs.

So how come when you look up BMR, the calculator doesn't ask for you peak weight and current weight? It only asked for your current weight.