Yes, that works. You can keep your food diary in parallel with the Fddb apps for iOS devices, Android devices and on the computer via the Fddb website. All your entries are synchronized with each other in real time between the devices. In order for all of this to work, you have to be logged in with the same Fddb account on all devices.
The Fddb app is not only available for smartphones, but also for Android tablets and the iPad.
If you are a premium user, Fddb Premium is automatically available on all your devices.
Please note that the same functions and data may not be available on all systems.