I lost 60 lbs starving on 1100-1200 cals/day with only 10% fat (~70% carbs & ~20% protein) and 10 hrs of frantic Powteresque exercise a week. I gained it all back of course because living like that FOREVER was impossible.

But 10 years later I was able to lose the same 60 lbs at the same rate while luxuriating on 1750-2000 cals/day of mostly fat (70% fat, ~5% carbs, ~25% protein) and only an hour of exercise per week. I have maintained the loss for 19 months - a first for me in 38 years of dieting. Living like this forever is easy.