Objectives  This study classified food consumed by patients during hemodialysis using K-means clustering analysis, observed the effect of different food type on blood glucose fluctuations during dialysis, and identified the food type beneficial to stabilize blood glucose.  Methods  The unit energy density index of every food was calculated based on its weight (in grams) and nutritional components (calories, carbohydrates, protein, and fat). K-means clustering was applied to categorize different food types.  Results  A total of 34 patients were enrolled in this study, with each type of food consumed by the patients regarded as one sample, yielding 144 samples in total. Four food groups were identified via clustering analysis: group 1 (high-sugar and high-fat), group 2 (high-carbohydrate), group 3 (low-density), and group 4 (high-protein). Different food group exerted significant effect on intradialytic blood glucose fluctuation: overall comparison showed H=61.593 and P=0.001; pairwise comparisons revealed significant differences in blood glucose change after food intake for one hour between the high-protein group and the high-sugar high-fat group (H=0.000, P＜0.01) as well as between the high-sugar high-fat group and the high-carbohydrate group (H=0.000, P＜0.01). The high-sugar high-fat group exhibited the most prominent glucose-raising effect [1.20 (0.70, 1.52) mmol/L]; blood glucose level generally decreased in the high-carbohydrate group [-1.20 (-2.08, -0.40) mmol/L] and the high-protein group [-1.31 (-2.08, 0.35) mmol/L]; the low-density group was associated with a slightly upward trend of blood glucose [0.30 (-1.50, 0.95) mmol/L].  Conclusions  High-protein food is recommended to the patients in the first hour of hemodialysis, followed by high-carbohydrate food. A small amount of high-sugar and high-fat food may be consumed in the final hour of dialysis. Large portions of low-energy-density food are not recommended on hemodialysis.