Well, there are lots of Miss Universe sites out there, and they all look exactly the same...lots of gorgeous and skinny women. Further reading of interviews with former winners concerning their weights show that a great many of them have a difficult time keeping the pounds off after they are crowned. Apparently, ramping-up to participate in the contest is the same as an Olympic athlete preparing for the games. Every bite is watched and workouts are religiously attended. After victory and the crown atop the head, the Miss Universe's schedule becomes intense, with lots of travel to other countries and lots of events and lots of time sitting on planes. None of these things lends itself to a regular gym schedule or diet.
I could not find any stats on weight at the time of the crowning, (the stats are for height) but there have been critical comments made about some winners after a few months into their one year reign. Miss Universe 2006 Zuleyka Rivera (Puerto Rico) was heavily criticized for weight gain. As a side note, the night of her crowning she fainted during a press conference, apparently due to the weight of her dress!!!!
1996 winner Alicia Machado from Venezuela was almost stripped of her title for weight gain and replaced by the first runner-up, but she was placed on a strict diet and fitness regime and allowed to stay on. Donald Trump, the head of the pageant, called Miss Machado "an eating machine" and stated that the winners were obligated to stay in perfect physical shape. I guess it's a good thing that the reigns are only for a year....for both the winner and the first runner-up, who I imagine keeps a close watch on any weight gains of Miss Universe!
http://www.foxnews.com/entertainment/2009/08/21/achieving-maintaining-physical-perfection-easy-task-pageant-contestants/
http://mentalfloss.com/article/22635/quick-10-10-miss-universe-controversies
https://www.google.ca/webhp?hl=en&tab=ww#hl=en&q=miss+universe+wiki