The Bolton fighter is in Las Vegas ahead of the biggest challenge of his glittering career.
Khan, 29, is stepping up two divisions to take on WBC middleweight champion Alvarez on Saturday night on the Strip?s brand new T-Mobile Arena.
The former world champion has competed as a lightweight, light-welterweight and welterweight, with the heaviest he has weighed in at being 10st 7lb.
But now he steps up to a catch-weight of 11st 1lb (155lb) to face big-punching Alvarez, who has lost just once in 47 fights.
It has led to a drastic change in diet from which he hopes will help him bulk up while also retaining his ferocious speed.
He said: ?In the past I would start cutting out the carbs a lot earlier but this time I can keep them high. Obviously that?s where the energy comes from.
?When I was making 140 and then also 147 I would still be eating but I would reduce the food massively during the week of a fight.
?I would hardly eat anything and I?d have to watch what I was drinking too. Now I can keep super hydrated all the time and eat at the right time.
?Sometimes just knowing you can eat helps your body feel good.?
Khan certainly looks a lot bulkier and feels he will not be dwarfed when he steps on the scales at Friday?s weigh-in.
