Comparison 3. Subgroup analysis – calorie content.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
3.1 Weight gain (g/kg/day) – high vs moderate	6	606	Mean Difference (IV, Fixed, 95% CI)	0.66 [0.51, 0.82]
3.1.1 Isocaloric	5	477	Mean Difference (IV, Fixed, 95% CI)	0.32 [‐0.19, 0.83]
3.1.2 Non‐isocaloric	1	129	Mean Difference (IV, Fixed, 95% CI)	0.70 [0.54, 0.86]
3.2 Length gain (cm/week) – high vs moderate	5	547	Mean Difference (IV, Fixed, 95% CI)	0.01 [‐0.01, 0.03]
3.2.1 Isocaloric	4	418	Mean Difference (IV, Fixed, 95% CI)	0.05 [0.01, 0.09]
3.2.2 Non‐isocaloric	1	129	Mean Difference (IV, Fixed, 95% CI)	0.00 [‐0.02, 0.02]
3.3 Head circumference gain (cm/week) – high vs moderate	5	549	Mean Difference (IV, Fixed, 95% CI)	0.00 [‐0.01, 0.02]
3.3.1 Isocaloric	4	420	Mean Difference (IV, Fixed, 95% CI)	0.00 [‐0.03, 0.04]
3.3.2 Non‐isocaloric	1	129	Mean Difference (IV, Fixed, 95% CI)	0.00 [‐0.02, 0.02]
3.4 Weight gain (g/kg/day) – moderate vs low	2	176	Mean Difference (IV, Fixed, 95% CI)	2.52 [2.10, 2.94]
3.4.1 Isocaloric	2	176	Mean Difference (IV, Fixed, 95% CI)	2.52 [2.10, 2.94]
3.4.2 Non‐isocaloric	0	0	Mean Difference (IV, Fixed, 95% CI)	Not estimable
3.5 Length gain (cm/week) – moderate vs low	3	217	Mean Difference (IV, Fixed, 95% CI)	0.09 [0.05, 0.14]
3.5.1 Isocaloric	2	176	Mean Difference (IV, Fixed, 95% CI)	0.09 [0.05, 0.14]
3.5.2 Non‐isocaloric	1	41	Mean Difference (IV, Fixed, 95% CI)	0.30 [‐1.89, 2.49]
3.6 Head circumference gain (cm/week) – moderate vs low	3	217	Mean Difference (IV, Fixed, 95% CI)	0.14 [0.10, 0.18]
3.6.1 Isocaloric	2	176	Mean Difference (IV, Fixed, 95% CI)	0.14 [0.10, 0.18]
3.6.2 Non‐isocaloric	1	41	Mean Difference (IV, Fixed, 95% CI)	0.30 [‐1.86, 2.46]