Based on, with small fixes:

• https://github.com/zewelor/ha_custom_components/tree/master/google_fit
• https://github.com/hemantkamalakar/haconfigs/tree/master/custom_components/google_fit
• https://github.com/vmanuel/hacs-google-fit

Creates Google Fit sensors. At the moment, the component provides following measurements:

• steps
• distance
• time
• calories
• weight
• height
• sleep
• heartrate

The sensors are designed to be flexible and allow customization to add new Google Fit dimensions with minimal effort with relative knowledge of Python and the Fitness Rest API.

• Have HACS installed, this will allow you to easily update.
• Add https://github.com/cyberjunky/home-assistant-google_fit as a custom repository with Type: Integration
• Click Install under "Google Fit" integration.
• Restart Home-Assistant.

• Copy directory custom_components/google_fit to your <config dir>/custom_components directory.
• Configure.
• Restart Home-Assistant.

In order to add this component as is, add a new sensor:

sensor:
  - platform: google_fit
    name: Google Fit
    client_id: your_client_id
    client_secret: your_client_secret

In order to generate your client_id and client_secret, see the prerequisites for the Google Calendar component: https://www.home-assistant.io/components/calendar.google/#prerequisites To make sensor work you have to enable the Fitness API in your project. In oder to enable Fitness API open Google Cloud console: https://console.cloud.google.com/apis/library/fitness.googleapis.com and enable API.

It is recommendable to store the client_id and client_secret as securely as possible. You can read about it on: https://www.home-assistant.io/docs/configuration/secrets/

Example:

  - platform: google_fit
    name: Bob
    client_id: !secret google_fit_client_id
    client_secret: !secret google_fit_client_secret

Add the relevant lines below to the configuration.yaml:

logger:
  default: info
  logs:
    custom_components.google_fit: debug