Table 3 Relationship between different types of dietary habits and self-reported students’ average grades using Spearman’s rank correlation (n = 608)

Traditional coffee

Number of times items consumed per day (categorical data)

r_s = -0.122

0.003*

Tea

Number of times items consumed per day (categorical data)

r_s = -0.115

0.005*

Instant coffee

Number of times items consumed per day (categorical data)

r_s = -0.168

 < 0.001*

Mate

Number of times items consumed per day (categorical data)

r_s = 0.019

0.64

Energy drinks

Number of times items consumed per week (categorical data)

r_s = -0.019

0.64

Natural fruit juice

Number of times items consumed per week (categorical data)

r_s = -0.014

0.74

Fruit

Number of times items consumed per week (categorical data)

r_s = -0.026

0.52

Vitamin C

Number of times items consumed per week (categorical data)

r_s = -0.007

0.87

Alcohol

Number of times items consumed per week (categorical data)

r_s = 0.077

0.06

Breakfast

Number of times items consumed per week (categorical data)

r_s = 0.033

0.41

Fast food

Number of times items consumed per week (categorical data)

r_s = -0.117

0.004*

Snacks

Number of times items consumed per week (categorical data)

r_s = -0.031

0.45

Scheduled eating (breakfast, lunch, dinner)

Categorical data (Yes; No)

t = -0.356

0.72

Cigarettes

Number of times items consumed per day (categorical data)

r_s = -0.026

0.53

Water pipe

Number of times items consumed per week (categorical data)

r_s = -0.067

0.10