You can switch between metric and imperial units at any time from your profile.
Steps
Go to your Profile and tap App Preferences.
Under Units, tap Measurement system to switch between metric and imperial.
You can also set individual overrides for Height units (centimeters or feet/inches) and Weight units (kilograms, pounds, or stones) if you prefer a mix.
Good to know
Switching units doesn't change your actual data — it just changes how it's displayed.
App Preferences is also where you choose which Carbs to track — Net Carbs or Total Carbs.
You can also switch units during onboarding when entering your height or weight — you don't have to wait until after setup.