Table 1 Population characteristics across quintiles of low carbohydrate diet scores in KNHANES 2016–2022 (N = 33,960)

Socio-demographic factors

Age, years

59.9 ± 0.28

51.2 ± 0.27

47.0 ± 0.25

44.1 ± 0.23

41.1 ± 0.25

Sex

   Men

2,472 (40.1)

3,327 (50.9)

3,352 (53.6)

3,123 (52.3)

2,282 (50.2)

   Women

4,416 (59.3)

4,117 (49.1)

3,895 (46.4)

3,805 (47.7)

3,171 (49.8)

Education

   Elementary school

2,542 (29.3)

1,410 (12.9)

788 (7.0)

515 (4.7)

293 (3.2)

   Middle school

1,022 (13.5)

899 (9.7)

703 (7.1)

459 (4.8)

294 (3.7)

   High school

1,543 (25.6)

2,085 (29.1)

2000 (27.6)

1,779 (24.2)

1,295 (22.2)

   College or higher

1,276 (24.5)

2,656 (43.5)

3,441 (54.2)

3,898 (62.2)

3,404 (67.7)

Household income

   Low

2,567 (30.9)

1,684 (17.9)

1,104 (12.0)

828 (9.9)

570 (8.7)

   Middle-low

1,791 (25.8)

1,956 (24.9)

1,802 (23.5)

1,584 (21.1)

1,163 (20.1)

   Middle-high

1,357 (22.7)

1,933 (28.1)

2,099 (30.9)

2,043 (30.8)

1,638 (30.6)

   High

1,141 (19.9)

1,843 (28.8)

2,227 (33.3)

2,453 (37.9)

2,077 (40.5)

Health-related behaviors

Body mass index, kg/m²

   <18.5

242 (3.8)

272 (4.2)

291 (4.2)

281 (4.3)

245 (4.7)

   18.5-<23.0

2,431 (36.0)

2,707 (36.5)

2,760 (37.1)

2,713 (38.7)

2,118 (37.6)

   23.0-<25.0

1,637 (23.4)

1,764 (23.5)

1,632 (22.5)

1,533 (21.3)

1,172 (21.5)

   ≥25.0

2,483 (35.6)

2,632 (35.1)

2,514 (35.7)

2,356 (35.1)

1,891 (35.7)

Smoking status

   Never

4,598 (64.2)

4,500 (56.7)

4,387 (57.0)

4,266 (58.6)

3,617 (62.4)

   Past

1,364 (20.0)

1,575 (21.9)

1,557 (21.8)

1,371 (19.9)

1,056 (20.8)

   Current

815 (14.1)

1,301 (20.5)

1,256 (20.5)

1,243 (20.9)

761 (16.5)

Alcohol consumption

   Never

1,479 (18.0)

961 (9.9)

652 (6.6)

517 (6.0)

329 (4.5)

   Past

1,606 (22.3)

1,397 (16.7)

1,175 (14.1)

1,049 (13.8)

779 (12.4)

   Current, < 2 times/wk

2,780 (43.4)

3,413 (49.3)

3,704 (53.9)

3,750 (56.1)

3,212 (61.0)

   Current, ≥ 2 times/wk

923 (14.7)

1,607 (23.2)

1,670 (24.7)

1,568 (23.5)

1,115 (21.7)

Physical activity, METs-min/wk

728.5 ± 21.8

922.8 ± 25.5

921.6 ± 21.5

1004.7 ± 24.6

1158.5 ± 28.8

Dietary intake

   Energy intake

1,588.6 ± 10.7

1,836.8 ± 10.7

1,957.5 ± 11.2

2,054.8 ± 11.8

2,106.2 ± 14.9

   Carbohydrate, %E

78.0 ± 0.07

66.8 ± 0.15

60.2 ± 0.13

54.0 ± 0.12

44.7 ± 0.14

   Protein, %E

10.8 ± 0.03

12.8 ± 0.04

14.4 ± 0.05

16.2 ± 0.06

19.4 ± 0.07

   Animal protein, %E

2.6 ± 0.03

5.0 ± 0.04

7.0 ± 0.05

9.3 ± 0.06

13.3 ± 0.08

   Plant protein, %E

8.2 ± 0.03

7.8 ± 0.03

7.4 ± 0.03

6.9 ± 0.03

6.0 ± 0.04

   Fat, % E

10.3 ± 0.06

15.6 ± 0.07

20.5 ± 0.08

25.6 ± 0.10

33.9 ± 0.12

   Plant fat, %E

3.0 ± 0.04

5.9 ± 0.05

8.7 ± 0.07

12.6 ± 0.10

19.6 ± 0.17

   Animal fat, %E

7.3 ± 0.06

9.8 ± 0.07

11.8 ± 0.09

13.0 ± 0.11

13.3 ± 0.01

   Fruit and vegetable, g/d

489.0 ± 6.2

470.2 ± 5.1

447.8 ± 4.7

429.4 ± 4.3

393.3 ± 4.8

   Fiber, g/d

26.1 ± 0.27

26.0 ± 0.20

25.7 ± 0.18

25.0 ± 0.18

22.9 ± 0.21

Medical condition

   eGFR, ml/min/1.73 m²

93.3 ± 0.28

98.8 ± 0.26

102.0 ± 0.24

103.8 ± 0.23

105.9 ± 0.26

   Uric acid, mg/dL

5.0 ± 0.02

5.2 ± 0.02

5.3 ± 0.02

5.3 ± 0.02

5.4 ± 0.02

   Diabetes, %

1,358 (17.4)

1,156 (13.0)

861 (10.1)

673 (8.2)

457 (7.1)

   Hypertension, %

3,333 (43.0)

2,845 (32.7)

2,255 (27.4)

1,744 (21.6)

1,140 (18.3)

   Hypercholesterolemia, %

2,052 (28.1)

2,000 (23.7)

1,721 (21.4)

1,555 (19.7)

1,142 (18.4)