It's tricky but this may do what you want. It'll work using flic connected to your iPhone but will have issues if the phone is locked. This is an apple issue.
- Create a Shortcut to add data to your health app (e.g. Nutrition data add 100ml on today's date) and give it a name e.g. Water100
- On the flic app for iphone set the action to be Safari (open a website in Safari) and give it the URL of:
The shortcut will run every time the flic is pressed.
Hope that helps,