Anyone one with enough will-power and motivation can lose a lot of 'weight' in a few weeks
IF they completely change their diet, spend most of their days exercising, and consume ONLY nutrition, rather than 'food.'
I did it myself – as you can read in YOUR SHAPE BACK. I completely stopped eating ALL my favourite 'foods' literally overnight. My motivation to do so was immense. I was no longer going to be deliberately poisoned (by manufactured food) for someone's PROFITS. Not for a single day longer.
Yes, I was sick, from all the symptoms of my body going through a severe detox. And it was hell to do. However, I stuck with it, and within two weeks I was almost skeletal. Alas, I did not take before and after photos, if I had the difference between the two would have sold any 'weight-loss' product on Earth!
Of course there, was no way though that I could sustain such 'weight' loss and a few weeks later (eating only a raw food diet) I attained my natural body shape.
The point I'm making here is – it IS possible to lose body fat very quickly. However, the quicker you lose it, the harder it is to sustain the loss for the long-term.
If you lose 'weight' - body fat - more slowly – one step at a time, you are also changing your lifestyle, attitude, habits, diet, and mindset permanently as you go along. And you will lose your 'weight' permanently by doing it this way, rather than it being just a temporary fix.