Lifestyle has a lot to do with it also. Their diet works great when you actually work for a living, I can’t imagine it being as healthy for this generation of twenty-somethings that haven’t worked up a sweat in years, if ever.
So true. About 4 years ago I weighed 215 with a 36 inch waist. I'm 6'2 so I didn't look too fat, but I didn't want to start buying new clothes. I cut out sugar and flour, and started playing racquetball every day. I'm down to 175 with a 32 inch waist. It was actually very easy.