Seventy-eight percent of adults enrolled in whole-day intermittent-fasting trials are no longer adhering at twelve months, per a 2025 BMJ review pooling adherence data across protocols and follow-up windows. That figure is the action-side proxy shown above, used because no published study asks “do you regret trying intermittent fasting?” head-on. Lapse rate is not regret rate. Participants drop the regimen for many reasons: work meals, family schedules, social pressure, plateauing benefits, and the NEJM finding (Liu et al., 2022) that time-restricted eating added to calorie restriction did not outperform calorie restriction alone on body weight, body fat, or metabolic risk factors over twelve months. Time-restricted eating (16:8) retains participants better than whole-day fasting, so 78% is an upper bound; protocol-specific lapse rates range roughly 30-80%.
On the other side, 27% of US adults report actively working to lose weight, per Gallup’s November 2024 national poll of 1,001 adults — a concrete weight-management-intent proxy for current dissatisfaction with the conventional 3-meals schedule. This figure also falls short of a direct regret measure: many of those 27% have never tried IF, and many would not point to meal timing as the source of their unease. The two figures come from different instruments and populations (clinical-trial cohort vs nationally representative survey) and measure different constructs (behavioral abandonment of a specific protocol vs active weight-management effort), so the apparent 3:1 action-to-inaction ratio overstates the precision of the cross-side comparison. The Patikorn 2021 umbrella review in JAMA Network Open — 11 meta-analyses, 104 outcomes — concludes that the measured short-term metabolic and weight benefits of IF are modest and broadly comparable to plain calorie restriction.
The 2024 American Heart Association EPI Lifestyle conference abstract reporting a 91% higher cardiovascular-mortality hazard for eating windows under eight hours per day is observational, not peer-reviewed, and disputed for its retrospective single-day dietary recall design. We mention it for context but do not lean on it. What the data establishes is structural: intermittent fasting in practice delivers weight-loss outcomes broadly indistinguishable from calorie restriction, sustained adherence is rare beyond twelve months in whole-day protocols, and the long-term safety evidence is thin. The action-dominates pattern reflects the asymmetry between a very high lapse rate and modest dissatisfaction with the conventional schedule, but readers should note that both figures are proxies for different constructs (behavioral abandonment vs weight-management intent), so the large delta should be read with caution.