Lose It! is a little more complex(?) in the sense we do full food and exercise tracking. But I do still have some insights into the observations they have written about.
We offer reminders to log your food if you have done so far today. Users can pick the time and then we use iOS notifications to remind them, similar to the way they remind users to log their weight. Tis feature is iOS only, no Android or web only version of it. If you compare users with reminders enabled to users without reminders enabled we see users with reminders enabled lose 1.8 more pounds. (8.4 vs 6.6lbs)
However there are two other observations that we see from the Lose it! base. First, weighing yourself daily is stressful. People get down on themselves all the time because they gained weight from one day to the next when they thought they were doing good. This is because people fluctuate weight so much day to day based on so many factors. Most users on the forums always recommend only weighing yourself once a week. We also had to build in a buffer range for users once they hit their goal weight because so many users complained that their weight moves around so much once they hit their goal weight they kept getting bumped back into a weight loss plan.
Another pattern we see is that users that have a Withings scale that automatically records their weight receive a lot of value (expressed in emails to us, posts on the forums, or written on their wall) from the device. We haven't had time to run stats (on how it effects weight) on this yet but we are starting to talk about the 'passive tracking' for users that have a Fitbit and a Withings connected to their Lose It!. Users cannot get over how much a better picture of their health they get after the values come in on their own. The Withings scale takes the textWeight idea to a new level. Sadly, both of these devices are pretty costly and out of the range of a lot of people. So textWeight might be a good way for people to track weight that are on a low cost budget.
All in all though, the most important feature that will improve your weight loss is accountability via social / friends both online or in real life. Studies have shown this in the past so we are not the first to notice or the first to say. In fact, this is the first thing out of the mouth of most health startup CEOs.