{"title":"Early Engagement and Recorded Weight Change with an AI Accountability Coach","subtitle":"A retrospective observational analysis","publisher":"BodyBuddy","author":"Francis John","reportNumber":1,"version":"1.0","publishedAt":"2026-08-22","studyType":"retrospective observational analysis","engagement":{"measure":"relative likelihood of being active (at least one message) in a later week, by days messaged in week 1, indexed to the 0-to-2-day group","groups":[{"label":"All 7 days","daysMessagedInWeekOne":"7","relativeLikelihood":{"week4":10.5,"week8":6.4,"week12":3.8}},{"label":"5 to 7 days","daysMessagedInWeekOne":"5 to 7","relativeLikelihood":{"week4":8.9,"week8":5,"week12":2.8}},{"label":"3 to 4 days","daysMessagedInWeekOne":"3 to 4","relativeLikelihood":{"week4":0.8,"week8":1.2,"week12":0.3}},{"label":"0 to 2 days","daysMessagedInWeekOne":"0 to 2","relativeLikelihood":{"week4":1,"week8":1,"week12":1}}],"headlineComparison":{"fiveOrMoreDays":106,"twoOrFewerDays":85,"relativeLikelihood":5}},"weight":{"measure":"median percentage change from first recorded weight to the median of recorded weights in a window from 14 days before to 3 days after each milestone","population":"members with a stated target weight at least 1 kg below baseline and a recorded weight in the milestone window","milestones":[{"weeks":4,"members":25,"medianChangePercent":-1.3,"meanChangePercent":-1.3,"lostAnyWeight":18,"lostThreePercentOrMore":4,"lostFivePercentOrMore":1,"changesPercent":[-5.77,-4.97,-3.96,-3.76,-2.85,-2.64,-1.88,-1.87,-1.82,-1.82,-1.71,-1.35,-1.31,-1.25,-0.73,-0.64,-0.1,-0.03,0,0.01,0.23,0.38,0.54,1.29,2.72]},{"weeks":8,"members":13,"medianChangePercent":-2.9,"meanChangePercent":-2.8,"lostAnyWeight":9,"lostThreePercentOrMore":6,"lostFivePercentOrMore":3,"changesPercent":[-6.68,-6.42,-6.16,-4.52,-4.39,-3.41,-2.92,-2.02,-1.81,0.07,0.16,0.76,1.09]},{"weeks":12,"members":6,"medianChangePercent":-3.9,"meanChangePercent":-4.4,"lostAnyWeight":5,"lostThreePercentOrMore":4,"lostFivePercentOrMore":2,"changesPercent":[-9.89,-7.33,-4.31,-3.52,-2.44,0.96]}],"scaleSyncedWeekFourMembers":5,"noLossGoalWeekFour":{"members":11,"medianChangePercent":-0.6},"pairedEightWeek":{"members":11,"medianAtFourWeeksPercent":-1.9,"medianAtEightWeeksPercent":-2.9,"lowerAtEightThanFour":9},"loggingSplitWeekFour":{"everyDay":{"members":11,"medianChangePercent":-1.8,"lostAnyWeight":11},"mostDays":{"members":14,"medianChangePercent":-0.1,"lostAnyWeight":7}}},"followUp":{"plannedFor":"November 2026","commitment":"Research Note 2 will re-run these definitions and be published whatever the numbers show."},"exclusions":["Internal and demonstration accounts.","Weights imported from another service.","Weights recorded before the member's account existed."],"limitations":["Observational design with no control group or random assignment; the analysis cannot establish causation.","Weight is observed only for members who continued to weigh in.","Most weights were entered by members rather than measured under a standardized protocol.","Weight samples are small, especially the six-member 12-week group.","Single program over a five-month window in 2026."],"citation":"John F. Early Engagement and Recorded Weight Change with an AI Accountability Coach: A Retrospective Observational Analysis. BodyBuddy Research Note 1. Version 1.0. Published August 22, 2026.","reportUrl":"https://bodybuddy.app/research/early-weight-trends"}