Summary of findings for the main comparison. Summary of Findings ‐ Ketogenic diets compared to control for people with epilepsy.

Ketogenic diets compared to control for people with epilepsy
Patient or population: people with epilepsy Settings: outpatients Intervention: ketogenic diets Control: control intervention (care as usual)
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No. of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Ketogenic diets
Seizure freedom (100% reduction in seizure frequency) Follow‐up: 2 months to 12 months	Proportion of individuals achieving seizure freedom ranged from 0% to 9% in the control groups	Proportion of individuals achieving seizure freedom ranged from 0% to 15% in the KD groups	Not estimable	350 (4 studies)	⊕⊕⊝⊝ Low1,2	No studies reported a statistically significant difference between KD and control.
Seizure reduction (50% or greater reduction in seizure frequency) Follow‐up: 2 months to 16 months	Proportion of individuals achieving 50% or greater reduction in seizure frequency ranged from 0% to 18% in the control groups	Proportion of individuals achieving 50% or greater reduction in seizure frequency ranged from 35% to 56% in the KD groups	Not estimable	452 (5 studies)	⊕⊕⊝⊝ Low1,2	All five studies reported a statistically significant advantage to the KD group over the control group.
Adverse effects Follow‐up: 2 months to 16 months	The most frequent adverse effects reported by participants in dietary intervention groups were: vomiting and constipation. Other adverse effects reported included diarrhoea, dysphagia, lethargy, lower respiratory tract infection, hyperammonaemic encephalopathy, weight loss, nausea, infections (pneumonia, sepsis), acute pancreatitis, decrease in bone matrix density, gallstones, fatty liver, nephrocalcinosis, hypercholesterolaemia, status epilepticus, acidosis, dehydration, tachycardia, hypoglycaemia, hunger,abdominal pain, clinically relevant reduction in height, hypercalcinaemia and renal stones.		Not estimable	452 (5 studies)	⊕⊕⊝⊝ Low1,2	Few statistically significant differences were found between the KD groups and control groups.
Cognition and behaviour Follow‐up: 16 months	One study reported significant increases in activity, productivity and less anxiousness in the KD group compared to control.		Not estimable	58 (1 study)	⊕⊕⊝⊝ Very low1,2,3
Quality of life Follow‐up:16 months	One study reported no significant difference in QUALYs between the KD group and control.		Not estimable	58 (1 study)	⊕⊕⊝⊝ Very low1,2,3
Attrition rate Follow‐up: 2 months to 16 months	Proportion of individuals withdrawing from the control group ranged from 0% to 40%	Proportion of individuals withdrawing from the KD group ranged from 8% to 35%	Not estimable	452 (5 studies)	⊕⊕⊝⊝ Low1,2	No studies reported a statistically significant difference between KD and control.
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; KD: ketogenic diet;QUALYs: quality‐adjusted life years.
GRADE Working Group grades of evidence High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate.

¹Downgraded once due to inconsistency: studies are heterogeneous with regards to interventions examined and comparisons made.
 ²Downgraded once due to risk of bias: some included studies were not blinded, had missing data or unclear methodological details reported.
 ³Downgraded once due to imprecision: low overall sample size. Confidence in results from small number of participants is low.