Oh, I see... you have the same experience on losing weight as a guy who has been on 40 different diet plans over 20 years and needs his stomach stapled.
The guy you describe does not know the first thing about nutrition. So in answer to your Q - No, GG does not share this pitiful experience (thankfully).
Losing weight particularly when obese is not rocket science. The equation is quite simple -- Don't eat too many calories. It is that simple. Really. The weight will come off. Granted, over longer term one needs to be concerned with getting proper nutrients but this isn't so difficult. Less calories is the key. Now getting to 5% or less bodyfat is not that easy to achieve. That takes real discipline and know how and determination. GG results are quite remarkable. You should be treating him with a little more respect for this.
Are you talking from experience? Getting from lean to very lean is not all that easy as it may seem. Body is doing all it can to conserve calories and add fat stores at those levels. It gets pretty damn efficient at finding every spare unburned calorie for fat. Your food intake is so low for so long can be difficult to get proper nutrients. Takes time, effort and know-how to do it safely. Where are you going with this?