You are probably right here...but I have noticed I stick to a diet more when I go in the opposite direction - and weigh myself 2-3 times a day. I feel the reason people say weigh yourself once per week is they dont' want to become obsessed with the diet, or depressed that they gained weight. But for me, weighing 3 times a day REALLY shows how much your weight fluctuates just drinking water and really teaches you what causes those changes - and makes the changes less meaningful. If i were to weigh myself on wednesday and be dehydrated and then come back a week later and be bloated and see that I did everything right and I was up 2 pounds without being able to realize I was comparing my old lowest weight to my new highest weight...I'd give up. I also think it's easier to let yourself get away with cheating if you don't step on a scale. If you slide a little and then the next day see that you gained weight, you KNOW what happened and take steps to turn the ship around. But if you slide a little, and the next day don't step on the scale...you don't know how bad the damage was and may keep going...until 5 days later you realize you wasted an entire week and weren't really dieting at all.Just watching the show! HGP, you should try just weighing yourself once a week on a Wednesday, that is far enough away from the weekend that any cheats should have fallen off, and Wednesday is considered the best day to get a true reading according to a few articles I read recently. Something to do with the adjustment between the weekend off and working during the week makes Wednesday the ideal time for a true weigh in. Trying to measure by the day is just going to make you nuts due to hormonal swings and what not causing changes in your hydration and or inflammation levels.
Just a workout that causes some inflammation can raise your weight by increasing the interstitial fluid levels due to inflammation.