TL;DR
Your top three margin×volume dishes should almost never sit under a deep platform promo. Discount the long tail to drive discovery — then upsell into the core.
Why your best-sellers are the "never-discount" tier. Run deals on the tail instead — and protect the dishes that pay the rent.
Protect the core
Your top three dishes by margin × volume are the engine of your delivery profit. When you blanket-discount them, you train customers to wait for promos and you shrink the margin on the items you sell most.
Where discounts belong
Use discounts on slow movers, new items, and bundles that pull people toward high-margin sides. A 10% off on a low-volume curry is cheap discovery. The same 10% on your #1 seller is expensive habit-forming.
The simple rule
Rank your menu by real earnings. Lock the top three from deep discounts. Promote the middle and tail. Your ROAS looks better when the items converting are the ones that actually pay.
Summary
Never discount your profit engine. Let promos do discovery work on the long tail while your best dishes stay priced to earn.
