Weight of Horses Post-Derby

[Merlinsky]

Nafzger talked about how little weight Street Sense lost post-Derby, something like 20 lbs. I assume this is good and considering how much horses weigh it sure seems low to me. Anyway can anybody talk about weight loss following major efforts and in particular what this amount of weight loss says about Street Sense? Do you expect a realist Preakness contender to gain weight over their Derby run or can they take a little hit, go in lighter, and still do it with their previous effort's flare?