I feel like 28 days fasting is too extreme for me but what I do is something called "intermittent fasting" and it has amazing health benefits as well as ability to drop weight fast.

I pretty much eat my daily 2500 calories is a span of 4 hours and the rest of the day im fasting, example(Eat from 1pm-5pm the amount of calories you need, then fast for 20 hours and start eating 1pm the next day).