Google Demand Gen campaigns — the successor to Discovery campaigns — use your Merchant Center product feed to power dynamic product ads across YouTube Shorts, Gmail, Google Discover, and Display Network placements. Unlike Performance Max which combines multiple signals, Demand Gen is specifically designed for upper-to-mid funnel activity: reaching people who are in market for your product category but haven't yet visited your website.
The feed requirements for Demand Gen overlap significantly with Google Shopping, but there are specific optimisations that matter more in Demand Gen's visual-first placement environments than they do in standard text-accompanied Shopping results.
What Demand Gen actually uses from your feed
Demand Gen's creative layer draws from several feed fields that Shopping campaigns de-emphasise:
Images: Demand Gen displays products in visual formats — YouTube Shorts overlays, Gmail promotional panels, Discover cards. Image quality matters significantly more here than in standard Shopping. The recommended minimum for Demand Gen placements is 1200×1200px square or 1200×628px landscape. If your primary Shopping images are 500×500px thumbnails, Demand Gen creative quality will suffer.
Lifestyle images (lifestyle_image_link): Demand Gen specifically supports lifestyle images — products shown in context rather than on white backgrounds. While Google Shopping often requires white-background hero images, Demand Gen performs better with lifestyle imagery that shows the product being used or worn. This is the primary reason to populate the lifestyle_image_link field in your feed.
Descriptions: Demand Gen uses product descriptions more heavily than Shopping in its AI-generated creative. Factual, evocative descriptions that convey the product's appeal (not just its specifications) work better for Demand Gen's awareness-stage audience than specification-heavy descriptions optimised for Shopping's purchase-intent audience.
Feed fields that unlock Demand Gen creative
In Trajekt, you can configure separate image rules for Demand Gen-targeted feeds versus standard Shopping feeds — using your lifestyle or contextual images as the primary image for a Demand Gen supplemental feed while keeping white-background images as the primary for Shopping. This lets you optimise images for each placement type without compromising your standard Shopping compliance.
Audience signals and product feed interaction
Demand Gen campaigns accept audience signals — customer lists, similar audiences, in-market segments — to guide who sees your product ads. Your product feed's google_product_category values interact with these audience signals: Google cross-references your product categories with its audience intent data to identify people who are in market for products in your categories.
Correct google_product_category assignment is therefore more valuable in Demand Gen than it might appear. A product miscategorised as "Apparel & Accessories" (top level) rather than "Apparel & Accessories > Clothing > Outerwear > Coats & Jackets" (specific) misses the audience signal matching that puts your jacket ads in front of people who have been researching jackets across Google's properties.
Performance Max vs Demand Gen: which uses your feed better
Performance Max and Demand Gen both use your product feed, but for different purposes. PMax uses your feed primarily for Shopping placements (where purchase intent is high) and secondarily for creative assets in upper-funnel placements. Demand Gen uses your feed primarily for upper-funnel placements with a product-first creative format.
The practical difference: PMax optimises toward direct conversion; Demand Gen optimises toward engagement and awareness that eventually converts. The two campaigns can run simultaneously and should be evaluated on different metrics — PMax on ROAS, Demand Gen on incrementality (are people who saw Demand Gen ads converting at higher rates than people who didn't?).
Feed quality improvements benefit both: better images improve creative quality across all formats; accurate categories improve audience matching in Demand Gen and query matching in PMax; complete GTINs improve product matching in both. A single feed investment in quality serves your entire Google Ads estate.
Trajekt is a UK-built product feed management platform. Our editorial team covers feed optimisation, Google Shopping strategy, ChatGPT commerce, and ecommerce channel management for UK merchants and agencies.