It's not a true forecast; I run a mean average between the linear trend and the 7-day moving average to get the approximation for the next week. Then it's interesting to see how closely the actual graph follows it.

Yep, I'm a data-geek. Having the numbers and seeing the different correlations I can plot makes it almost a game. I just made a chart for Caitlin that plots her calorie breakdown (fat/carb/protein) against her daily fluctuation; we're trying to see if tweaking her foods can make a difference.