Table 2.

Characteristics of data synthesis of included randomised controlled trials (n = 2).

Author, Year, Study Design, Location	Sample Size N	Population Characteristics	Participants, N, Program Name Characteristics of Digital Intervention	Type of Diets Prescribed Intervention/Control	Primary Outcomes	Intervention/Follow-Up Period	Retention, Adherence	Risk of Bias
Saslow et al. (2017) Pilot RCT a Parallel-group, USA [42]	25	Overweight adults (>18) with T2DM b, mean age 53.0 (IG c), 58.2 (CG d) years Patients receiving insulin (except for metformin) excluded	IG c—N = 12, dietary instruction provided via weekly email lessons with lifestyle recommendations and mindfulness training CG d—N = 13 dietary instructions provided via weekly emailed lessons. No lifestyle recommendations or mindfulness training included	IG c: VLCD e ad libitum. (20–50 g/carbs per day), to induce nutritional ketosis CG d: ADA f “create your plate” plan from the American Diabetic Association (low-fat diet)	HbA1c change	16-week intervention, 32-week follow-up	92% retention Drop out: IG c: 8% (1/12) CG d: 46% (6/13)	Positive No Blinding Self-report dietary intake
Chen et al. (2020) Pilot RCT a Single blinded China [17]	100	Adults (30–80 years) with prediabetes, mean age 54.9 (IG c), 51.9 (CG d) years. Patients taking medication excluded	IG c N = 57 Health management support service system. Mobile app (CAReNA). Receive LCD g dietary guidance CG d—N = 43 Received early education in diabetes diet management	IG c: LCD g (70–130 g/carbs per day). CG d: Diabetes diet education. No LCD g intervention.	HbA1c change	3 months	-	Positive

^a RCT: randomized controlled trial, ^b T2DM: type 2 diabetes mellitus, ^c IG: intervention group, ^d CG: control group, ^e VLCD: very low carbohydrate diet, ^f ADA: American Diabetes Association, ^g LCD: low carbohydrate diet.