Posted: 15/06/2015 at 14:00
How long ago was the race? A lot of the apparent weight gain after an ultra can be down to water retention as during and after prolonged activity the kindneys go into partial shut down to allow the body to cling on to as much moisture as possible. That is why taking things like ibrufen during such events is now strongly advised against as it can lead to kidney damage.
I have found that it can take several weeks for things to return to normal. After that you might have to start blaming the food!