From skwigg's journal:
A single scale reading has no impact on what or how much I eat that day. That's part of not celebrating low numbers or cracking down on high ones. Fluctuations are normal and mildly entertaining at best, not a reflection of success or failure. So, every day I eat satisfying meals, I'm physically hungry before them, I rarely snack, I eat exactly what I want, I stop when I'm pleasantly full but not stuffed, and I eat plenty of nutritious whole foods. Those are my habits whether my weight is up, down, or sideways.
If the trend (not that morning's weight but weeks of readings) is headed up, it usually means I've gotten loose with some of my habits. Maybe snacks are creeping in more often, or hunger is not quite happening, or food quality has been hilarious. Carrot cake is a vegetable right? :-D In that case, all I ever need to do is return to my habits.
I actually have the opposite issue too. I don't need to lose weight, so if my readings are trending down and bumping the bottom of my range, again I look at the habits. Maybe I'm ignoring hunger too often, eating not quite enough instead of just enough, or getting carried away with the salads. I return to my habits and my weight returns to its happy place. This is over a period of weeks. It's gentle and subtle adjustments. It's not rewarding or depriving myself today based on this morning's number. That kind of reactive drama is what causes people to do an extra hour of cardio if their weight is up, or to binge because it's down, or to binge because it's up! Rather than helping the situation, that fuels more instability and emotional distress. Instead, I focus on my habits, the big picture, trends over time, consistency, curiosity, kindness, and humor. That's less stressful and dramatically more effective.
The whole purpose is to feel great! Punishing yourself for gaining or sabotaging yourself for losing is never going to feel great.