WeightAide

WeightAide for Apple Watch allows you to view your weight as stored in Apple Health directly from your watch.
New weight entries can be added directly from your watch which are added to Apple Health.
A graph view showing all weight data from Apple Health is available from your watch.
Identical functionally is provided by the iPhone version of the app.
Please note, when used in standalone mode the Watch version of the WeightAide app will one show a graph of the most recent weeks worth of weight data. Also install the iPhone version of the app to allow the full set of weight data held in Apple Health to be requested by the Watch version of the app.
The iPhone and Watch graph screens can show views of 1 day, 1 week, 1 month, 3 month, 1 year, 3 year and 10 year timeframes.
Tap the iPone or Watch graph to step through the available zoom levels, from x1, x5, x10 to x20.
Swipe the iPhone or Watch graph right or left to scroll along the timeline.
Swipe the iPhone or Watch graph up or down to scroll up or down the weight scale.
A number of complications are available on the Watch to display your current weight on the different types of watch faces.