Make the trendline on the weight chart LINEAR
A moving average is not very useful here, but a linear trendline allows you to gauge where you'll be in the next month or year if the trend continues. Having said that, it would also be nice to be able to extend the chart into the future to see where the trend line hits.
By the way, I'm loving this app. I didn't want to use an app at first, but now I'm very happy. Thank you!