Table 1. Baseline Demographics and Anthropometric and Metabolic Variables.
| Healthy Low-Fat Diet (n = 305) | Healthy Low-Carbohydrate Diet (n = 304) | |
|---|---|---|
| Sex, No. (%) | ||
| Women | 167 (54.8) | 179 (58.9) |
| Men | 138 (45.2) | 125 (41.1) |
| Age, mean (SD), y | 39.3 (6.8) | 40.2 (6.7) |
| Highest level of education achieved, No. (%)a | ||
| <High school degree | 2 (0.6) | 2 (0.6) |
| High school degree | 5 (1.6) | 11 (3.6) |
| Some college | 63 (20.7) | 67 (22.0) |
| College degree | 102 (33.4) | 106 (34.9) |
| Some postgraduate school | 25 (8.2) | 12 (3.9) |
| Postgraduate degree | 107 (35.1) | 103 (33.9) |
| Race/ethnicity, No. (%)b | ||
| White | 176 (57.7) | 182 (59.9) |
| Hispanic | 67 (22.0) | 61 (20.1) |
| Asian | 30 (9.8) | 30 (9.9) |
| African American | 10 (3.3) | 13 (4.3) |
| American Indian, Alaskan Native, or Pacific Islander | 3 (1.0) | 0 |
| Other | 19 (6.2) | 18 (5.9) |
| Weight, mean (SD), kg | ||
| Women | 90.7 (11.5) | 88.9 (12.5) |
| Men | 105.7 (13.9) | 106.8 (13.7) |
| Both sexes | 97.5 (14.7) | 96.3 (15.7) |
| Body mass index, mean (SD)c | ||
| Women | 33.3 (3.4) | 32.9 (3.4) |
| Men | 33.5 (3.4) | 33.8 (3.4) |
| Both sexes | 33.4 (3.4) | 33.3 (3.4) |
| Body fat %, mean (SD)d | ||
| Women | 41.0 (3.9) | 40.4 (4.0) |
| Men | 29.9 (4.5) | 30.3 (4.7) |
| Both sexes | 36.3 (6.9) | 36.5 (6.6) |
| Waist circumference, mean (SD), cme | ||
| Women | 103.5 (10.4) | 102.6 (10.5) |
| Men | 111.8 (9.7) | 112.7 (9.9) |
| Both sexes | 107.2 (10.9) | 106.7 (11.4) |
| Blood lipid level, mean (SD), mmol/L | ||
| High-density lipoprotein cholesterol | 1.28 (0.23) | 1.29 (0.24) |
| Low-density lipoprotein cholesterolf | 2.89 (0.79) | 2.94 (0.68) |
| Triglycerides | 1.45 (0.80) | 1.45 (1.03) |
| Blood pressure, mean (SD), mm Hgg | ||
| Systolic | 122.9 (12.5) | 122.9 (12.4) |
| Diastolic | 81.0 (7.3) | 81.2 (7.8) |
| Fasting glucose, mean (SD), mg/dL | 98.6 (8.6) | 98.5 (9.7) |
| Fasting insulin, mean (SD), μIU/mL | 15.9 (13.5) | 15.5 (8.0) |
| Insulin-30, mean (SD), μIU/mLh | 95.1 (67.5) | 91.8 (61.7) |
| Metabolic syndrome, No. (%)i | 106 (34.8) | 100 (32.9) |
| Respiratory exchange ratio, mean (SD)j,k | 0.861 (0.065) | 0.862 (0.058) |
| Resting energy expenditure, mean (SD), kcalj,k | 1651 (283) | 1629 (293) |
| Energy expenditure, mean (SD), kcal/kg/dj,l | 32.6 (1.7) | 32.5 (2.2) |
| Genotype, No. (%)m | ||
| Low fat | 130 (42.6) | 114 (37.5) |
| Low carbohydrate | 83 (27.2) | 97 (31.9) |
| Neither | 70 (23.0) | 76 (25.0) |
SI conversion factors: To convert glucose to mmol/L, multiply by 0.0555; high-density and low-density lipoprotein cholesterol to mg/dL, divide by 0.0259; insulin to pmol/L, multiply by 6.945; triglycerides to mg/dL, divide by 0.0113.
There were missing data for 1 participant in the low-fat group and 3 participants in the low-carbohydrate group.
Determined by self-report using fixed categories.
Calculated as weight in kilograms divided by height in meters squared.
Available only for cohorts 2 through 5 because additional funding became available for use of dual-energy x-ray absorptiometry and technician time. There were missing data for 77 participants in the low-fat group and 66 participants in the low-carbohydrate group. In addition, 37 participants in the low-fat group and 28 participants in the low-carbohydrate group declined being measured.
There were missing data for 3 participants in the low-fat group and 2 participants in the low-carbohydrate group.
There were missing data for 1 participant in the low-carbohydrate group.
There were missing data for 2 participants in the low-fat group and 1 participant in the low-carbohydrate group.
Indicates the blood concentration of insulin at the 30-minute time point of an oral glucose tolerance test. There were missing data for 3 participants in the low-fat group.
Defined by Adult Treatment Panel III guidelines from the National Cholesterol Education Program.26
Available only for cohorts 2 through 5 because additional funding became available for metabolic cart and technician time.
There were missing data for 41 participants in the low-fat group and 40 participants in the low-carbohydrate group.
There were missing data for 23 participants in the low-fat group and 33 participants in the low-carbohydrate group.
There were missing data for 22 participants in the low-fat group and 17 participants in the low-carbohydrate group.