OBJECTIVE: Prospective studies on relationships between hedonic hunger and BMI (Body Mass Index) during weight management are lacking. This study examined if hedonic hunger reduced during a behavioural weight management programme, and if hedonic hunger predicted future BMI. METHODS: Participants were 594 community-dwelling, UK-based adults(396 female; age 56.43 years, s.d. = 12.50, range 20-83 years); 490 participants (82.5%) had obesity. Participants were randomised to a 12- or 52-week behavioural weight management intervention (WW12 or WW52, respectively) or a brief self-help intervention (BI). Relationships between hedonic hunger and BMI over 24 months (baseline, 3, 12, 24 months) were analysed using an autoregressive cross-lagged model. RESULTS: Hedonic hunger scores decreased from 2.71 (s.d. = .91) at baseline to 2.41 (s.d. = .88) at 3 months (p < .001, CI .22 to .38), remained reduced to 24 months, and were not affected by intervention arm at any time point (p's>.05). Baseline hedonic hunger scores predicted 3-month scores (B = .76, SE = .03, p < .001, CI .71 to .82), 3-month scores predicted 12-month scores (B = .76, SE = .03, p < .001 CI .72 to .80), and 12-month scores predicted 24-month scores (B = .72, SE = .03, p < .001, CI .64 to .77). Higher hedonic hunger at 3 months predicted higher BMI at 12 months (B = .04, SE = .02, p = .03, CI .01 to .07) but not at 24 months (p>.05). BMI at 12 months was lower in WW52 30.87kg/m2, s.d. = 5.02) than WW12 (32.12 kg/m2, s.d. = 5.58, p = .02, CI .16 to 2.34) and BI (32.74 kg/m2, s.d. = 4.15, p = .01, CI .30 to 3.45). BMI was not affected by intervention at any other time point (p's>.05). CONCLUSION: Hedonic hunger reduced during weight management irrespective of intervention. Early reductions in hedonic hunger appear to be associated with lower BMI in the medium-term. Identifying ways to reduce hedonic hunger during weight loss could aid weight management for some people.