INTERMITTENT fasting decreased symptoms of long COVID-19 in a randomised crossover trial that compared the efficacy and safety of 4 weeks of 1–2-day fasting plus a restricted diet versus 4 weeks of mild time-restricted eating (TRE) and a restricted diet. Long COVID-19 is a common, often-debilitating condition that can impair social connections and daily functioning, and there are currently no clinically proven treatments.
A total of 60 participants were randomised to treatment A or treatment B for 4 weeks, then swapped to the other treatment for 4 weeks. Treatment A (TRE) consisted of a no-sugar and optionally no wheat diet, with a 10–12-hour daily eating window followed by 12–14 hours of water-only fasting. Treatment B (fasting) was a no-sugar diet with an 8-hour daily eating window and 16 consecutive hours of daily fasting, as well as a once weekly 23–60-hour water-only fast (length selected by the participant). Symptoms were assessed using weekly online surveys. Primary outcomes included changes in long COVID-19 symptom severity scores (LC-Scores) and the number of long COVID-19 symptoms (numLCsym) between treatments, and secondary outcomes were changes in these scores over the 10-week trial.
Results showed that fasting was superior to TRE alone in reducing LC-Scores. In the fasting group, numLCsym decreased by −5.0 in 4 weeks, compared to −1.4 in the TRE group. Furthermore, numLCsym decreased by 40.6%, and mean LC-Score decreased by 51.8% during the 10-week regimen of a no-sugar diet, TRE, and fasting. There were no major adverse safety events recorded.
In conclusion, both fasting interventions led to decreased long COVID-19 symptoms, with the more intense fasting regimen being significantly more effective. Further research is needed to validate this potential treatment.
Reference
Bunker T et al. Intermittent fasting and a no-sugar diet for long COVID symptoms: a randomized crossover trial. Sci Rep. 2025;15(1):27563.