Joker's right. Everyone has a tendency to expand as we take in food and drink throughout the day. And yes, you will expand when you stand up vs laying down.
Ok thanks but today I took measurements and I grew a whole 5 inches!!!
Oh that is called bloating. Pretty much in most people it is your intestines filling up with whatever your taking in.
Keep in mind the gut you have as you lie down will expend when you stand up.
I dont know but I KNOW for a fact I get bigger because in the morning when I flex my ab muscles there is no change but as the day goes on and I eat and drink I get wayy bigger because when I flex my abs there is a huge change.