Silverbirch - if you just once weigh yourself both naked and again in the bathrobe of your choice (or pajamas, or whatever), you will from then on know what the weight of the attire is, and can subtract it from your total. If I've just solved a perennial problem for you, you're welcome :>)
Dagmar - your comment reminds me of the "gratefuls" exercise one of DS's middle school teachers taught us a few years back. At the end of the day, each member of the family has to publicly share at least one thing that happened that day for which they are grateful. We did it for a few weeks and indeed had higher levels of "life satisfaction" for awhile, though it eventually became somewhat stale and forced, and we stopped.
I enjoyed the wedding, I enjoyed the dancing and the food and seeing family members (of DH's) that I haven't seen in years. Yes I ate more than I have in several weeks, but I don't feel at all guilty- it was a planned indulgence - and today I'm back on plan.
Happy Mother's Day to all of you for whom it's relevant.