Emerging preclinical data suggests dietary interventions, including intermittent fasting, may play a key role in altering cancer progression. In a feasibility trial monitoring cellular, clinical, and qualitative changes, ten patients with chronic lymphocytic leukemia followed time-restricted eating for three months, and five patients for six months. Seven of fifteen participants (47%) experienced a decrease or stabilization in malignant lymphocyte counts on time-restricted eating, while malignant lymphocyte accumulation slowed in five participants (33%) or had no effect in three participants (20%). A reduction in malignant lymphocyte counts were accompanied by an unexpected decline in cellular autophagy in malignant lymphocytes. Metabolite profiling identified microbial-derived bile acid metabolites, glycoursodeoxycholic, taurochenodeoxycholic, glycolithocholic and ursodeoxycholic acid, and short-chain fatty acids, dehydrolithocholic and apocholic acid, that changed with time-restricted eating. Participant quality of life improved during time-restricted eating. These results connect time-restricted eating with shifts in autophagy, microbial-derived metabolites, tumor progression, and quality of life.

The authors have declared no competing interest.

clinicaltrials.gov, ID Number NCT04626843

Thank you to the BC Cancer Foundation (F2005888 to E.S. and N.M.) and to the Canadian Institutes of Health Research (PJT192015 to J.J.L.) for funding this study.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Harmonized research ethics board approval was granted on May 26, 2020, with the University of British Columbia- BC Cancer Research Ethics Board as the harmonized board of record and the University of Victoria as the harmonized partner board (REB Number H19-03072).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

The data used in the analyses are available via the Open Science Framework at https://osf.io/yv62c/. All R code is available via the Open Science Framework at https://osf.io/yv62c/. Complete plots can be viewed on the Open Science Framework website at https://osf.io/yv62c/. Any additional data will be made available from the lead contact upon request.

https://osf.io/yv62c/