Deep Dive: Why You Should be Paying Closer Attention to your Sizing Approach (Hint: it's Not GLP-1s)

Sizing may not get the same attention as assortment planning, allocation or inventory optimization, but getting it wrong can have a significant impact on retail margins. When core sizes sell out while others linger on clearance racks, retailers face lost sales, excess inventory and frustrated customers. In this special Retail Remix Deep Dive, host Kate Robertson sits down with James Theuerkauf, VP of Product at Anaplan and Co-founder of Syrup Tech, which Anaplan acquired in 2025. They explore whether sizing has become more challenging — and not because of the high uptake of GLP-1 weight loss drugs — as well as how advances in data and AI are helping retailers make more granular decisions and why better sizing can improve everything from full-price sell-through and customer loyalty to sustainability.Key TakeawaysWhy apparel sizing remains an overlooked source of margin erosion despite its impact on stockouts, overstocks and customer loyaltyHow rapidly changing trends, increasingly complex assortments and shifting consumer preferences are making historical size curves less reliableWhy retailers should be cautious about blaming GLP-1 adoption for broad shifts in sizing demand and instead focus on their own customer and product dataHow advances in AI and granular data are helping planners build smarter size curves while keeping human expertise at the center of decision makingWhy more accurate size planning can reduce overproduction, markdowns and excess inventory while creating a more sustainable apparel supply chainRelated Links⁠Learn more about AnaplanGet more retail industry insights from Retail TouchPointsSubscribe and catch up on all episodes of Retail RemixRead: Torrid, Circana and PwC Executives Discuss How GLP-1s Are Impacting Retail