Table 1.
Baseline Characteristics of the Study Participants.*
| Characteristic | Low-Fat, Average- Protein Group (N = 204) | Low-Fat, High-Protein Group (N = 202) | High-Fat, Average- Protein Group (N = 204) | High-Fat, High-Protein Group (N = 201) | All Participants (N = 811) | Participants Who Completed the Study (N = 645) |
|---|---|---|---|---|---|---|
| Age — yr | 51±9 | 50±10 | 52±9 | 51±9 | 51±9 | 52±9 |
| Sex — no. (%) | ||||||
| Female | 126 (62) | 135 (67) | 125 (61) | 129 (64) | 515 (64) | 397 (62) |
| Male | 78 (38) | 67 (33) | 79 (39) | 72 (36) | 296 (36) | 248 (38) |
| Race or ethnic group — no. (%)† | ||||||
| White | 159 (78) | 158 (78) | 165 (81) | 161 (80) | 643 (79) | 525 (81) |
| Black | 33 (16) | 33 (16) | 28 (14) | 33 (16) | 127 (16) | 88 (14) |
| Asian | 1 (<1) | 1 (<1) | 1 (<1) | 2 (1) | 5 (1) | 3 (<1) |
| Hispanic | 8 (4) | 7 (3) | 9 (4) | 5 (2) | 29 (4) | 23 (4) |
| Other | 3 (1) | 3 (1) | 1 (<1) | 0 | 7 (1) | 6 (1) |
| Height — m | 1.69±0.09 | 1.67±0.08 | 1.68±0.09 | 1.68±0.09 | 1.68±0.09 | 1.68±0.09 |
| Weight — kg | 94±16 | 92±13 | 92±17 | 94±16 | 93±16 | 93±16 |
| Body-mass index‡ | ||||||
| Mean | 33±4 | 33±4 | 32±4 | 33±4 | 33±4 | 33±4 |
| 25.0–29.9 — no. (%) | 51 (25) | 54 (27) | 60 (29) | 58 (29) | 223 (27) | 183 (28) |
| ≥30.0 — no. (%) | 153 (75) | 148 (73) | 144 (71) | 143 (71) | 588 (73) | 462 (72) |
| Waist circumference — cm | 104±13 | 102±12 | 103±14 | 104±13 | 103±13 | 104±13 |
| Hypertension — no. (%) | 70 (34) | 70 (35) | 67 (33) | 80 (40) | 287 (35) | 233 (36) |
| Use of medication — no. (%) | ||||||
| Antihypertensive agents | 54 (26) | 58 (29) | 55 (27) | 61 (30) | 228 (28) | 192 (30) |
| Lipid-lowering agents | 32 (16) | 48 (24) | 40 (20) | 31 (15) | 151 (19) | 128 (20) |
| Smoking status — no. (%) | ||||||
| Current smoker | 8 (4) | 5 (2) | 8 (4) | 10 (5) | 31 (4) | 24 (4) |
| Former smoker | 84 (41) | 59 (29) | 80 (39) | 75 (37) | 298 (37) | 241 (37) |
| Never smoked | 112 (55) | 138 (68) | 116 (57) | 116 (58) | 482 (59) | 380 (59) |
| Educational level — no. (%) | ||||||
| High school or less | 23 (11) | 15 (7) | 19 (9) | 19 (9) | 76 (9) | 65 (10) |
| Some college | 47 (23) | 47 (23) | 45 (22) | 41 (20) | 180 (22) | 132 (20) |
| College graduate or beyond | 134 (66) | 140 (69) | 140 (69) | 141 (70) | 555 (68) | 448 (69) |
| Marital status — no. (%) | ||||||
| Married | 132 (65) | 146 (72) | 144 (71) | 143 (71) | 565 (70) | 448 (69) |
| Divorced or separated | 36 (18) | 24 (12) | 33 (16) | 29 (14) | 122 (15) | 94 (15) |
| Widowed | 8 (4) | 4 (2) | 4 (2) | 2 (1) | 18 (2) | 16 (2) |
| Never married | 28 (14) | 28 (14) | 23 (11) | 27 (13) | 106 (13) | 87 (13) |
| Household income — no. (%) | ||||||
| <$50,000 | 56 (27) | 45 (22) | 48 (24) | 46 (23) | 195 (24) | 153 (24) |
| $50,000 to <$100,000 | 79 (39) | 82 (41) | 78 (38) | 84 (42) | 323 (40) | 260 (40) |
| $100,000 to $150,000 | 46 (23) | 43 (21) | 43 (21) | 32 (16) | 164 (20) | 123 (19) |
| >$150,000 | 21 (10) | 30 (15) | 33 (16) | 36 (18) | 120 (15) | 100 (16) |
| Information not provided | 2 (1) | 2 (1) | 2 (1) | 3 (1) | 9 (1) | 9 (1) |
| Risk factors | ||||||
| Blood pressure — mm Hg | ||||||
| Systolic | 118±13 | 120±13 | 120±13 | 120±15 | 119±13 | 119±14 |
| Diastolic | 75±9 | 75±9 | 76±9 | 76±10 | 75±9 | 75±9 |
| Glucose — mg/dl | 93±12 | 92±17 | 92±12 | 92±13 | 92±14 | 92±12 |
| Insulin — μU/ml | 12±7 | 12±8 | 12±7.5 | 12±8 | 12±8 | 12±7 |
| HOMA | 2.8±1.9 | 2.8±2.2 | 2.9±1.9 | 2.8±1.9 | 2.8±2 | 2.8±1.9 |
| Cholesterol — mg/dl | ||||||
| Total | 199±38 | 203±36 | 203±37 | 204±35 | 202±37 | 202±37 |
| LDL | 124±33 | 126±32 | 128±32 | 126±31 | 126±32 | 125±32 |
| HDL | 49±15 | 49±13 | 48±12 | 51±16 | 49±14 | 49±15 |
| Triglycerides — mg/dl | 135±82 | 144±79 | 147±93 | 141±85 | 142±85 | 144±87 |
| Dietary intake per day§ | ||||||
| No. of participants who provided information | 103 | 106 | 105 | 102 | 416 | 330 |
| Energy — kcal | 2015±505 | 1862±566 | 2012±597 | 1979±599 | 1966±570 | 1978±563 |
| Carbohydrate — % | 44±8 | 46±8 | 45±8 | 44±7 | 45±8 | 45±8 |
| Fat — % | 38±6 | 36±6 | 37±5 | 38±6 | 37±6 | 37±6 |
| Saturated fat — % | 12±3 | 12±3 | 12±3 | 12±2 | 12±3 | 12±3 |
| Protein — % | 18±4 | 18±4 | 18±3 | 18±3 | 18±3 | 18±3 |
| Dietary fiber — g | 18±7 | 17±7 | 18±6 | 17±6 | 17±7 | 18±7 |
| Cholesterol — mg | 303±121 | 278±120 | 306±135 | 305±134 | 298±128 | 298±128 |
| Alcohol — g | 6±8 | 4±7 | 6±9 | 6±9 | 5±8 | 5±8 |
| Respiratory quotient | 0.84±0.04 | 0.84±0.04 | 0.85±0.05 | 0.84±0.04 | 0.84±0.04 | 0.84±0.04 |
*
Plus–minus values are means ±SD. To convert the values for glucose to millimoles per liter, multiply by 0.05551. To convert the values for cholesterol to millimoles per liter, multiply by 0.02586. To convert the values for triglycerides to millimoles per liter, multiply by 0.01129. HDL denotes high-density lipoprotein, HOMA homeostasis model assessment of insulin sensitivity, and LDL low-density lipoprotein.
†
Race or ethnic group was reported by the participants.
‡
The body-mass index is the weight in kilograms divided by the square of the height in meters.
§
Data are from a 50% random sample.