first off, Go4It looks fantastic - great physique, lean, high paying job, full head of hair
as for his "naturalo" claims, he's at least "clean" in most of the pictures - he doesn't have the fullness in the delts and traps that are clear signs of being "on"
maybe he used pro-hormonas back in the day like BIG Fat ACH but chooses not to mention it - that's his business either way
regarding the discussion on calories and whatnot as a natural/clean, I can offer some insight
back when I was a naturalo and even when I go "off" I still do PT twice a day most days - cardio/circuit training in the morning, weights after work - occasionally cardio twice a day
under this program I too maintain between 155-165 lbs of brutal mass, lean as a cock but certainly not galeniko shredded
I find that the only factor that forces me to cut back to PT once a day or to take a day off (other than laziness) is not eating enough - due mostly to fear of getting fat
however, when I go away on "business trips" and have access to unlimited food, I too take advantage and truly "go for it"
the key difference between my eating and his would be the carbs - I'd wager I eat less than 50g total of incidental carbs per day so 600 seems astronomical
that part I can't really explain
keep in mind though that G4I does at least an hour of FASTED cardio every morning and walks around all day - doing real cardio (fast runs, sprints, stairs - NOT power-walking like an old lady) increases your metabolism, elevates your mood, and boosts your energy
sustaining all that requires calories
most here don't go for the health look so they don't have the same experience with serious cardio
for what it's worth, from my own personal experience and working with extremely fit people, G4I's claims are not at all unbelievable