Comparison 1. Low‐carbohydrate weight‐reducing diets versus balanced‐carbohydrate weight‐reducing diets in overweight and obese participants without T2DM (weight‐reducing phase only).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Change in body weight (kg) at 3 to < 12 months	37	3286	Mean Difference (IV, Random, 95% CI)	‐1.07 [‐1.55, ‐0.59]
1.2 Change in body weight (kg) at 3 to < 12 months: subgroup similarity of energy prescription	37	3286	Mean Difference (IV, Random, 95% CI)	‐1.07 [‐1.55, ‐0.59]
1.2.1 Similar energy prescriptions or approaches to restriction in both diets	27	2370	Mean Difference (IV, Random, 95% CI)	‐0.48 [‐0.85, ‐0.11]
1.2.2 Different, ad libitum energy in treatment diet and restricted in control diet	7	655	Mean Difference (IV, Random, 95% CI)	‐1.84 [‐3.07, ‐0.62]
1.2.3 No prescriptions reported or unrestricted for both diets	3	261	Mean Difference (IV, Random, 95% CI)	‐2.71 [‐4.20, ‐1.22]
1.3 Change in body weight (kg) at 3 to < 12 months: subgroup extent of carbohydrate restriction	37	3286	Mean Difference (IV, Random, 95% CI)	‐1.07 [‐1.55, ‐0.59]
1.3.1 Very low carbohydrate/ketogenic	9	494	Mean Difference (IV, Random, 95% CI)	‐2.29 [‐3.45, ‐1.13]
1.3.2 Low carbohydrate/non‐ketogenic	24	2256	Mean Difference (IV, Random, 95% CI)	‐0.36 [‐0.75, 0.03]
1.3.3 Incremental increase from very low to low carbohydrate	4	536	Mean Difference (IV, Random, 95% CI)	‐1.51 [‐2.89, ‐0.13]
1.4 Change in body weight (kg) at 3 to < 12 months: subgroup diagnosed cardiovascular event or disease	37	3286	Mean Difference (IV, Random, 95% CI)	‐1.07 [‐1.55, ‐0.59]
1.4.1 None	25	2799	Mean Difference (IV, Random, 95% CI)	‐0.88 [‐1.40, ‐0.37]
1.4.2 Mixed or unclear	12	487	Mean Difference (IV, Random, 95% CI)	‐2.24 [‐3.03, ‐1.45]
1.5 Change in body weight (kg) at 3 to < 12 months: subgroup gender	37	3286	Mean Difference (IV, Random, 95% CI)	‐1.07 [‐1.55, ‐0.59]
1.5.1 Mixed	22	2401	Mean Difference (IV, Random, 95% CI)	‐1.05 [‐1.64, ‐0.46]
1.5.2 Males	3	187	Mean Difference (IV, Random, 95% CI)	‐0.25 [‐1.70, 1.21]
1.5.3 Females	12	698	Mean Difference (IV, Random, 95% CI)	‐1.35 [‐2.37, ‐0.33]
1.6 Change in body weight (kg) at 3 to < 12 months: sensitivity analysis overall risk of bias	10		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.6.1 Some concerns	10	785	Mean Difference (IV, Random, 95% CI)	‐0.72 [‐1.78, 0.33]
1.7 Change in body weight (kg) at 3 to < 12 months: sensitivity analysis attrition domain	11		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.7.1 Low attrition	11	810	Mean Difference (IV, Random, 95% CI)	‐0.73 [‐1.75, 0.30]
1.8 Change in body weight (kg) at 3 to < 12 months: sensitivity analysis source of funding	20		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.8.1 Without diet/food industry funding	20	2183	Mean Difference (IV, Random, 95% CI)	‐1.20 [‐1.97, ‐0.43]
1.9 Change in body weight (kg) at ≥ 12 months	14	1805	Mean Difference (IV, Random, 95% CI)	‐0.93 [‐1.81, ‐0.04]
1.10 Change in body weight (kg) at ≥ 12 months: sensitivity analysis attrition domain	3	373	Mean Difference (IV, Random, 95% CI)	‐2.81 [‐4.50, ‐1.11]
1.11 Change in body weight (kg) at ≥ 12 months: sensitivity analysis source of funding	9		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.11.1 Without food/diet industry funding	9	1280	Mean Difference (IV, Random, 95% CI)	‐0.62 [‐1.81, 0.56]
1.12 Number of participants per group with weight loss of at least 5% at 3 to < 12 months	3	161	Risk Ratio (M‐H, Random, 95% CI)	1.30 [1.00, 1.68]
1.13 Number of participants per group with weight loss of at least 5% at ≥ 12 months	2	137	Risk Ratio (M‐H, Random, 95% CI)	1.11 [0.94, 1.31]
1.14 Change in BMI (kg/m2) at 3 to < 12 months	21		Mean Difference (IV, Random, 95% CI)	Totals not selected
1.15 Change in BMI (kg/m2) at ≥ 12 months	5	490	Mean Difference (IV, Random, 95% CI)	‐0.61 [‐0.99, ‐0.23]
1.16 Number of participants per group with reduction in BMI of at least 5% at 3 to < 12 months	1	55	Risk Ratio (M‐H, Fixed, 95% CI)	1.57 [0.79, 3.12]
1.17 Change in DBP (mmHg) at ≥ 12 months	11	1419	Mean Difference (IV, Random, 95% CI)	‐0.09 [‐1.29, 1.12]
1.18 Change in SBP (mmHg) at ≥ 12 months	11	1397	Mean Difference (IV, Random, 95% CI)	‐1.37 [‐2.99, 0.24]
1.19 Change in LDL cholesterol (mmol/L) at ≥ 12 months	13	1494	Mean Difference (IV, Random, 95% CI)	0.04 [‐0.05, 0.12]
1.20 Change in HDL cholesterol (mmol/L) at ≥ 12 months	13	1519	Mean Difference (IV, Random, 95% CI)	0.06 [0.02, 0.10]
1.21 Change in non‐HDL cholesterol (mmol/L) at ≥ 12 months	2	225	Mean Difference (IV, Random, 95% CI)	0.06 [‐0.20, 0.33]
1.22 Change in total cholesterol (mmol/L) at ≥ 12 months	11	1291	Mean Difference (IV, Random, 95% CI)	0.01 [‐0.10, 0.12]
1.23 Change in triglycerides (mmol/L) at ≥ 12 months	13	1559	Mean Difference (IV, Random, 95% CI)	‐0.11 [‐0.16, ‐0.06]
1.24 Constipation at 3 to < 12 months	4	564	Risk Ratio (M‐H, Random, 95% CI)	1.06 [0.81, 1.38]
1.25 Constipation at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.63 [0.32, 1.25]
1.26 Diarrhoea at 3 to < 12 months	2	244	Risk Ratio (M‐H, Random, 95% CI)	0.98 [0.33, 2.93]
1.27 Diarrhoea at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.32 [0.03, 3.05]
1.28 Nausea at 3 to < 12 months	2	244	Risk Ratio (M‐H, Random, 95% CI)	0.73 [0.05, 10.68]
1.29 Nausea at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.14 [0.01, 2.65]
1.30 Flatulence at 3 to < 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.75 [0.44, 1.30]
1.31 Flatulence at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.68 [0.39, 1.17]
1.32 Heartburn at 3 to < 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.53 [0.21, 1.36]
1.33 Heartburn at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.49 [0.23, 1.01]
1.34 Halitosis at 3 to < 12 months	1	263	Risk Ratio (M‐H, Fixed, 95% CI)	1.99 [1.32, 2.99]
1.35 Stomach upset at 3 to < 12 months	1	96	Risk Ratio (M‐H, Fixed, 95% CI)	1.00 [0.41, 2.45]
1.36 Appetite change at 3 to < 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.19 [0.01, 3.99]
1.37 Appetite change at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.49 [0.05, 5.25]
1.38 Fatigue at 3 to < 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.80 [0.47, 1.36]
1.39 Fatigue at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.91 [0.49, 1.71]
1.40 Headaches at 3 to < 12 months	2	244	Risk Ratio (M‐H, Random, 95% CI)	1.25 [0.26, 6.02]
1.41 Headaches at ≥ 12 months	1	148	Risk Ratio (M‐H, Fixed, 95% CI)	0.49 [0.25, 0.93]
1.42 Reported anxiety at 3 to < 12 months	1	60	Risk Ratio (M‐H, Fixed, 95% CI)	1.00 [0.07, 15.26]
1.43 Total mood disturbances (participant‐reported) at 3 to < 12 months	1	118	Mean Difference (IV, Fixed, 95% CI)	1.91 [‐8.06, 11.88]
1.44 Total mood disturbances (participant‐reported) at ≥ 12 months	1	118	Mean Difference (IV, Fixed, 95% CI)	2.87 [‐8.48, 14.22]
1.45 Depressive symptoms (participant‐reported) at 3 to <12 months	1	217	Mean Difference (IV, Fixed, 95% CI)	‐0.30 [‐1.36, 0.76]
1.46 Anxiety symptoms (participant‐reported) at 3 to < 12 months	1	217	Mean Difference (IV, Fixed, 95% CI)	‐0.20 [‐1.44, 1.04]