Table 1. Basic characteristics and scale scores of the included articles.

First author	Year of publication	Number of cases (n)	Experimental group (n)	Control group (n)	Intervention (experimental group vs. control group)	Outcome indicators
Dock-Nascimento (19)	2012	24	12	12	Fasting for 8 hours, oral carbohydrate 200 mL 2 hours before surgery vs. fasting and drinking for 8 hours	Postoperative insulin resistance
Faria (20)	2009	21	11	10	Fasting for 8 hours, oral carbohydrate 200 mL 2 hours before surgery vs. fasting and drinking for 8 hours	Postoperative insulin resistance
Itou (21)	2012	274	135	139	Fasting for 12 hours, oral carbohydrate 500 mL 2 hours before surgery vs. fasting and drinking for 12 hours	Hunger, thirst, anxiety, nausea, vomiting, gastric fluid volume, gastric fluid pH
Järvelä (22)	2008	101	50	51	Fasting for 12 hours, oral carbohydrate 400 mL 2 hours before surgery vs. fasting and drinking for 12 hours	Nausea, vomiting
Singh (23)	2015	10	5	5	Fasting for 8 hours, oral carbohydrate 200 mL 2 hours before surgery vs. fasting and drinking for 8 hours	Postoperative insulin resistance
Yildiz (24)	2013	60	30	30	Fasting for 8 hours, oral carbohydrate 200 mL 2–3 hours before surgery vs. fasting and drinking for 8 hours	Weakness, thirst, fasting, malaise, fatigue, nausea, concentration difficulty, gastric volume, gastric fluid pH