The Advertising Standards Authority has banned a Huel promotional advert featuring Spencer Matthews because it irresponsibly suggested that an exclusively Huel-based diet was compatible with elite athletic performance. In the podcast-style video posted to social media in April and May, the former Made In Chelsea star recounted meeting ultramarathon runner James Izzard, who he claimed consumed only Huel and won a 260km Amazonian endurance race by a significant margin, finishing nine hours ahead of his nearest rival. The ASA ruled that the advert encouraged harmful dietary practices by presenting this Huel-only diet as an acceptable way to fuel exceptional sporting achievement, particularly given that founder Julian Hearn did not adequately challenge Matthews's claims during the conversation.

Huel had argued that the video was intended to dispel misconceptions about its product being a total meal replacement, with the founder noting that ideally people should consume nutritionally complete whole food. However, the ASA found that despite these caveats, the final message of the advert contradicted its initial tone of scepticism by directly attributing the runner's exceptional performance to consuming no conventional food whatsoever. James Izzard, the actual race winner, is an experienced endurance athlete who has completed gruelling events including the Marathon des Sables and raised thousands for charity; Matthews himself finished third in the same race.