I must be missing something, because I don't see how this can work. There are so many things that can cause weight to fluctuate during the day, including fluids consumed, sodium causing water retention, time of the month (for women), how much fiber you've had (and bathroom habits)...a myriad of things. It is not the amount of food you eat in and of itself that causes weight gain, it is the calories and what is in the food.
This is purely hypothetical, but suppose I take a day and every time I'm hungry (and weighing less on the scale, in your model), I eat a handful of calorically dense food like raisins, nuts, chocolate chips. Those calories, day after day, are going to add up and I will gain weight. However, it won't happen fast enough that it would show up on the scale by the time of my next weighing (I don't know for sure, but I sincerely doubt calorie overage to weigh gain is instantaneous). Contrast that to a day in which I feel hungry and eat something like watermelon, much less calorically dense but much heavier due to its water content. I bet by the next time I'm on the scale that day, the weight of the watermelon I ate, added to my previous weight, puts me higher than the handful of nuts did.o
I can see where it sounds like a good idea in theory, but it doesn't make sense to me in practice. We have had a number of people on these boards who have commented about their weight loss overall who have weighed more than once a day and always come out heavier at night. Many people here weigh themselves first thing, naked, after using the bathroom, and to me that seems to be the lowest you will get for the day. I think the only way this would make sense is if you ate no sodium and if your bathroom habits were such that you urinated/defecated exactly the weight of whatever you ate before you weighed again, and who does that? And even so, it doesn't take the calories into account.
I also feel that it sets up a dangerous precedent for skipping meals and going too long without eating, which can wreck your metabolism and blood sugar and lead to bingeing. "Oh, I'd really like to have dinner, but I'm not under what I was when I weighed before lunch, so no food for me." And I probably wouldn't be able to eat at all the days I'm on my period!
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days