n8n Workflow: Track Meal Nutrition from Photos with LINE, Google Gemini, and Google Sheets

This n8n workflow automates the process of extracting nutritional information from meal photos, analyzing it with Google Gemini, and logging the data into a Google Sheet. It's designed for users who want to easily track their dietary intake by simply sending a photo of their meal.

What it does

This workflow streamlines nutrition tracking through the following steps:

1. Receives a Meal Photo: It listens for incoming webhook requests, typically triggered by a user sending a meal photo via a messaging app like LINE (though the specific LINE trigger isn't in the provided JSON, it's implied by the directory name).
2. Downloads the Image: It extracts the image URL from the incoming data and downloads the meal photo from Google Drive.
3. Analyzes with Google Gemini: The downloaded image is sent to the Google Gemini Chat Model along with a prompt to describe the meal and provide nutritional information (e.g., calories, protein, carbs, fat).
4. Extracts Nutritional Data: The response from Google Gemini is processed to extract the relevant nutritional details.
5. Formats Data: The extracted nutritional data is then formatted into a structured format suitable for storage.
6. Logs to Google Sheets: Finally, the formatted nutritional information (meal description, calories, protein, carbs, fat) is appended as a new row to a specified Google Sheet.

Prerequisites/Requirements

To use this workflow, you will need:

• n8n Instance: A running instance of n8n.
• Google Account: For Google Drive and Google Sheets.
  • Google Drive Credential: Configured in n8n to allow downloading images.
  • Google Sheets Credential: Configured in n8n to allow writing to a spreadsheet.
• Google Gemini API Key/Access: Configured as a credential in n8n for the Google Gemini Chat Model.
• Webhook Trigger: An external service (e.g., LINE, Telegram, etc.) configured to send image URLs to the n8n webhook URL.

Setup/Usage

1. Import the Workflow: Import the provided JSON into your n8n instance.
2. Configure Credentials:
   • Set up your Google Drive credential.
   • Set up your Google Sheets credential.
   • Set up your Google Gemini Chat Model credential.
3. Configure Google Drive Node (Node 58):
   • Ensure the "Resource" is set to "File" and the "Operation" is "Download".
   • The "File ID" should dynamically pull the file ID from the incoming webhook data. This likely comes from a previous node that parses the webhook payload.
4. Configure Google Gemini Chat Model Node (Node 1262):
   • Provide a clear prompt for Gemini to analyze the meal photo and extract nutritional data.
   • Ensure the image data from the Google Drive download is passed correctly to this node.
5. Configure Edit Fields (Set) Node (Node 38):
   • Adjust the expressions to parse the output from the Google Gemini Chat Model and extract specific nutritional values (e.g., calories, protein, carbs, fat) and the meal description.
6. Configure Google Sheets Node (Node 18):
   • Specify the "Spreadsheet ID" and "Sheet Name" where you want to log the nutritional data.
   • Ensure the "Operation" is set to "Append Row".
   • Map the fields from the "Edit Fields (Set)" node (e.g., Meal Description, Calories, Protein, Carbs, Fat) to the corresponding columns in your Google Sheet.
7. Activate the Workflow: Once configured, activate the workflow.
8. Trigger the Webhook: Configure your external application (e.g., LINE bot) to send an image URL to the "Webhook" node's URL when a user sends a meal photo. The webhook payload should contain the image URL or file ID that Google Drive can access.