Table 1.

PICOS study inclusion criteria

Preclinical studies
(P)opulation	Animal model such as as activity-based anorexia (ABA), or gnotobiotic humanized rodents transplanted with gut microbiota of AN patients (gAN)
(I)ntervention	ABA (food restriction and free access to a running wheel), or faecal microbiota transplantation (FMT) of AN patients
(C)omparison	Mice with ad libitum access to food, without free access to a running wheel as a control for ABA mice. Gnotobiotic mice transplanted with the gut microbiota of normal weight individuals (gNW) as a control for gAN
(O)utcomes	Phenotypical differences between gAN and gNW (behaviour, weight, or others). Microbiota composition in ABA model
(S)tudy design	Experimental design
Clinical studies
(P)opulation	Individuals with AN
(I)ntervention	FMT, treatment with pre-, probiotics or no specified intervention
(C)omparison	NW (normal-weight) control group or no control group
(O)utcomes	The primary outcomes collected were information regarding microbiota analysis in patients with AN (relative or absolute abundance, diversity indices), differences between AN patients and NW controls for these parameters, correlations between microbiota composition and psychopathological parameters, faecal metabolites concentrations (SCFAs, BFCAs or others), effects of FMT, or other applied interventions
(S)tudy design	Randomized or non-randomized, cross-sectional, longitudinal, case series or single-case studies