If that character had been a diabetic very long, he should have known better than to try that "juicing" fad diet. If the juices lacked sugars, he should have crashed in insulin shock, possibly fatal. If the juices did have sugars, they would have had him on a blood sugar roller coaster, as the sugars would be mostly quickly assimilated and quickly dissipated simple sugars. Weight loss is a complicated thing for diabetics, and he should have gotten his doctor to pre-approve whatever he attempted, and maybe monitor his progress. Given his inclination to try this fad diet, I suspect he's pretty suspicious and negative about "Western Medicine".
Similarly, the "realization" he posted in Post #12 is something he should have known beforehand, and been another reason not to attempt this fad diet. During the period of weight loss the person doing it should also develop and practice the kind of diet and physical routines that (s)he will live for the rest of their lives. IOW, precisely what this fad diet was not.
The thread was begun nearly 3 years ago. I wonder whether he's still alive and how well he might be. Not that any diet/exercise combo would have been effective against the ideological fat in his head.