Does changing product feed in Google Merchant centre affect google shopping campaigns performance?
Hi guys! I’ve been running Google Shopping Ads for my clients for quite some time. Recently, i was having issues with the feed and I uploaded another primary feed and deleted the existing one.
Will it affect my shopping campaigns? Plus will the campaign start fresh with fresh data with the new product feed?
I’m kind of confused.
The short answer is:
Yes, changing your primary product feed, especially by deleting the existing one and uploading a new one, will significantly affect your Google Shopping campaigns and performance data.
The core issue lies in the possibility of changing the unique item_id attribute for your products.
If the new feed uses different item_id values for the same products, all historical performance data (clicks, conversions, impressions) linked to the old IDs in Google Ads will be lost for the new product entries.
Your campaigns, particularly those using Smart Bidding or Performance Max, will enter a re-learning phase because Google’s machine learning models rely heavily on this historical data tied to the item_id.
The campaign will not start “fresh” with zero data, as it still retains account-level history, but the product-specific performance data and bidding signals will be reset for all products with changed IDs, causing a likely temporary dip in performance as the system relearns.
To manage this at scale and avoid campaign disruption, you should automate product updates using the Merchant API (formerly Content API for Shopping) or the new Google Merchant API, focusing on partial updates to avoid full feed replacement.
The long answer is:
The confusion is entirely understandable, as the linkage between Google Merchant Center (GMC) product data and Google Ads campaign performance is complex and hinges on a single critical data point: the item_id attribute.
Your action of deleting the old feed and uploading an entirely new one creates a high-risk scenario for performance stability.
If the product identifiers – the item_id values – in your new primary feed are different from those in your old feed, Google Ads treats these as entirely new products, even if the titles and images are the same.
This severs the link to the invaluable historical performance data that Google’s automated bidding strategies, like Target ROAS or Maximise Conversion Value, use for their optimisation decisions.
Consequently, the bidding algorithms must enter a re-learning phase, which typically results in significant performance fluctuations for several days or even a couple of weeks, depending on the volume of data.
The campaign will not start entirely fresh in the Google Ads sense, as campaign-level data and other assets remain, but the core product-level signals that drive bidding and ad serving are essentially reset for every product whose item_id has changed.
A robust and cost-effective solution for managing product data and preventing this disruption is to implement a direct, programmatic synchronization using the Google Merchant API.
This API, which is replacing the older Content API for Shopping, allows you to execute small, targeted, incremental updates rather than requiring the complete replacement of the primary feed file.
Instead of deleting and re-uploading an entire primary feed, a well-implemented integration would use the API to only insert or update the specific product fields – like price, availability, or title – that have actually changed in your CRM or eCommerce system.
This ensures that the product’s stable identifier, the item_id, remains constant in GMC, preserving its historical performance data in Google Ads and thus preventing the campaign from going into a disruptive re-learning period.
This method is cost-effective because it reduces manual feed management time, minimises ad spend wastage during performance dips, and keeps your campaign’s high-value historical data intact for optimal Smart Bidding and Performance Max campaign efficiency.
Furthermore, for advanced data analysis and segmentation of this performance, an integration using the Google Ads API can pull product-level metrics directly into an internal data warehouse like BigQuery or a reporting tool like Looker Studio, allowing you to quickly spot and address any performance anomalies post-feed change.
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