This idea is exactly how my and Bethany Soule's pet project, kibotzer.com, started. It has worked great for a bunch of family and friends (although they often

This idea is exactly how my and Bethany Soule's pet project, kibotzer.com, started. It has worked great for a bunch of family and friends (although they often yo-yo back when they stop reporting their weight to kibotzer!). A tweak to your broccoli vs pizza day (great way to put it!): It's hard to take broccoli day seriously if it's just a random fluctuation. So we have a Yellow Brick Road that you follow to your goal. The centerline of the Road is what you call the line from C to D. And then there's a right and wrong lane of the Yellow Brick Road (lane width dynamically adjusts to account for random fluctuation) and broccoli mode starts in earnest when you're in the wrong lane and in danger of going off the Road. The biggest failure mode of kibotzer/lineardiet seems to be painting yourself into a corner by going above the line a bit planning to catch back up, and then a bit more, until it's hopeless. We have a bunch of ideas for how to address that...