I couldn’t find any reliable public information (interviews, social media posts, news, or transcripts) from David Sacks, Jason Calacanis, or third-party sources that report or compare their body weights around late summer 2021.

Because their exact weights at that time are private and apparently never disclosed in a verifiable way, there is no factual basis to determine whether David Sacks actually weighed less than Jason Calacanis by the end of summer 2021. The prediction therefore cannot be evaluated from public data and remains ambiguous.