You don't need a smart band, an ankle bracelet, internet-connected scale or anything. Everything you need is provided from the phone - from sleep tracking to steps taken each day.
As you enter your weight every day, Argus Health will plot the data on a graph so you can easily see how you're doing. It also graphs a line which shows your average weight over time to make the correlation even clearer.
To track your calories, the app suggests you take a picture of your food. However, this must be done as you log it (you can't log a saved picture - you need to take a picture from within the app for it to work).
Many users have mentioned that while the screen is off the app missed recording most of the steps (50-70% of the steps were missed). Obviously this isn't great, as it provides an inaccurate step or drains your battery by keeping the screen on continuously.