Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet.

BACKGROUND: Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates. METHODS: In this 2-year trial, we randomly assigned 322 moderately obese subjects (mean age, 52 years; mean body-mass index [the weight in kilograms divided by the square of the height in meters], 31; male sex, 86%) to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie. RESULTS: The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively. The relative reduction in the ratio of total cholesterol to high-density lipoprotein cholesterol was 20% in the low-carbohydrate group and 12% in the low-fat group (P=0.01). Among the 36 subjects with diabetes, changes in fasting plasma glucose and insulin levels were more favorable among those assigned to the Mediterranean diet than among those assigned to the low-fat diet (P<0.001 for the interaction among diabetes and Mediterranean diet and time with respect to fasting glucose levels). CONCLUSIONS: Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions. (ClinicalTrials.gov number, NCT00160108.)

Effect of changes in the intake of weight of specific food groups on successful body weight loss during a multi-dietary strategy intervention trial.

BACKGROUND: Distinct weight loss dietary strategies are associated with changes in specific food groups. OBJECTIVE: To address the effect of changes in specific weight of food groups on weight loss in a 2-year low-fat, Mediterranean, low-carbohydrate intervention trial (DIRECT). METHODS: We assessed changes in the intake of 12 food groups among 322 participants (body mass index [BMI] = 31 kg/m(2); age = 52 years; 86% men), using a validated electronic food frequency questionnaire. RESULTS: The weight of the 3592.9 ± 1558 (g/d ± SD) of baseline food consumed consisted mainly of liquids, excluding water (32.6% of total weight of food); vegetables (18.8%), fruits (17.7%), dairy (9.0%), meat (7.7%), and bread/cereal/pasta/potatoes (7.1%). Participants significantly reduced food intake by 283.73 ± 1342 (g/d ± SD) at 6 months and by 963.36 ± 1869 (g/d ± SD) at 24 months (p < 0.05 as compared with baseline). Food weight changes were similar across diet groups (p = 0.366), whereas 6-month body weight loss was -4.6 ± 4.4 kg, -4.7 ± 4.9 kg, and -6.4 ± 6.6 kg for low-fat, Mediterranean, and low-carbohydrate groups, respectively; p < 0.026). In multivariate regression models, adjusted for age, sex, baseline body weight, and changes in weight intake of 12 food groups (g/d), independent dietary predictors (standardized-ß) at 6 months (rapid weight loss phase) were as follows: decreased consumption of sweets and cakes (ß = 0.493; p = 0.008) in the low-fat group, tendency toward increased crude legumes (ß = -0.196; p = 0.061) in the Mediterranean group, and increased vegetable intake (ß = -0.249; p = 0.018) in the low-carbohydrate diet group. In the entire group, in models further adjusted for diet type, leading predictors for rapid weight loss phase were as follows: increased vegetables by ~140 g/d (ß = -0.116; p = 0.045) and decreased intake of sweets and cakes by ~30 g/d (ß = 0.162; p = 0.010). Universal predictors for 2-year successful weight loss in the entire group were as follows: increased intake of vegetables (ß = -0.192; p = 0.007) and meat (ß = -0.146; p = 0.026) and decreased intake of eggs (ß = 0.187; p = 0.003), processed legumes (ß = 0.195; p = 0.002), and beverages (ß = 0.135; p = 0.032). CONCLUSIONS: Two-year weight loss is associated with a decrease of ~1 kg of total food consumed and may be achieved by a variety of changes in specific food groups within different diet strategies. Universal predictors of successful weight loss in the rapid weight loss phase across all diet strategies are increasing the weight of intake of vegetables and decreasing the weight of intake of sweets and cakes.

Life prevalence of upper respiratory tract diseases and asthma among children residing in rural area near a regional industrial park: cross-sectional study.

INTRODUCTION: The study described was initiated by the Israel Ministry of Health as an effort to respond to and deal with public concern about possible health disorders related to odorous emissions (composed of a great many of organic and inorganic chemicals) from the regional industrial park (IP) in the Negev, southern Israel. Previous ecological studies found that adverse health effects in the Negev Bedouin population were associated with residential proximity to the IP. The objective of the current study was to investigate a hypothesis concerning the link between the IP proximity and life prevalence (LP) of upper respiratory tract chronic diseases (URTCD) and asthma in children aged 0-14 years living in rural Negev, Israel, in small agricultural communities. METHODS: The cross-sectional study was conducted in 7 localities simultaneously during 2002. The following indirect exposure indicators were used: (1) distance (less than 20 km/ more than 20 km) from the IP ('distance'); (2) presence (yes/no) of the dominant wind direction being from the IP toward a child's locality ('wind direction'); and (3) the child's mother having made odour complaints (yes/no) related to the IP ('odour complaints'). A 20 km cut-off point was used for 'distance' dichotomization as derived from the maximum range of 'odour complaints'. This gave 3 proximal and 4 distant localities, and division of these by the 'wind direction' gave one versus two localities. The study population consisted of 550 children born in the localities. Medical diagnoses were collected from local clinic records. The following were included in the interviewer-administered questionnaire for a child's parents: (1) demography (the child's birth date, gender, mother being married or not, parental origin and education, number of siblings); (2) the child's birth history (pregnancy and delivery) and breast-feeding duration; (3) the child's parental respiratory health; and (4) environmental factors (parental smoking and occupational hazardous exposure, domestic use of pesticides, domestic animals, outdoor odour related to the IP emissions). For statistical analysis, Pearson's chi(2), t-tests and multivariate logistic regressions were used, as well as adjusted odds ratios (OR) within a 95% confidence interval. RESULTS: The multivariate analysis showed that increased LP of URTCD in children of proximal localities was statistically significant when associated with odour complaints (OR = 3.76 [1.16, 12.23]). In proximal localities, LP of URTCD was higher (at borderline level statistical insignificance p = 0.06) than in distant localities (OR = 2.31 [0.96, 5.55]). The following factors were found to be related to the excess of the LP of URTCD: (1) father's lower education (by distance: OR = 2.62 [1.23, 5.57]; by wind direction: OR = 4.07 [1.65, 10.03]); (2) in-vitro fertilization (by distance: OR = 3.03 [1.17, 7.87]; by wind direction: OR = 4.34 [1.48, 12.72]). In proximal localities, the increase in asthma LP was associated with: (1) wind direction (OR = 1.95 [1.01, 3.76]); (2) a child's male gender (OR = 2.95 [1.48, 5.87]); and (3) a child's mother's having had an acute infectious disease during pregnancy (OR = 4.84 [1.33, 17.63]). CONCLUSIONS: An increased LP of chronic respiratory morbidity among children living in small agricultural localities in the Negev was found to be associated with indirect measurements of exposure (distance, wind direction and odour complaints) to IP emissions. These results, in conjunction with previously reported findings in the Negev Bedouin population, indicate a need for environmental protection measures, and monitoring of air pollution and the health of the rural population.

Respiratory morbidity in hospitalized Bedouins residing near an industrial park.

The residents' concern about exposure to a chemical industrial park (IP), which includes the national toxic industrial waste site, prompted the authors to initiate this ecological study on the association between residing near the IP and being hospitalized for respiratory ailments in the local Bedouin population. The population was stratified by sex, age, and locality type (permanent settlements and traditional tribal settlements). The distance and wind direction from the IP were used as exposure indicators. Hospitalization data were obtained from the regional medical center. Increased hospitalization rates for chronic obstructive pulmonary disease and all respiratory diseases were found to be associated with residential proximity to the IP. Attributable risk for chronic obstructive pulmonary disease was 34.2% in male members of the traditional tribal settlements and 49.3% in female members of the permanent settlements.

Dietary evaluation and attenuation of relative risk: multiple comparisons between blood and urinary biomarkers, food frequency, and 24-hour recall questionnaires: the DEARR study.

Estimates of diet-disease relative risks (RRs) suffer from inaccuracies introduced by dietary measurement errors. Using the "method of triads," by which the validity coefficient (VC) of the dietary assessment method and "true" long-term intake could be estimated from 3 pairwise correlations between the FFQ, the reference method, and the biomarker, the authors evaluated the performance of a newly developed FFQ. Over a period of 13 mo (September 2000 to September 2001), 161 participants completed 3 FFQs and six 24-h recalls (24HRs), and supplied 2 blood samples and three 24-h urine collections. For protein, beta-carotene, and folic acid, the VCs of the FFQ with the "true intake" (0.77, 0.65, and 0.72, respectively) were relatively higher than the VCs of 24HRs (0.68, 0.60 and 0.39, respectively). Among the biomarkers, the VCs of serum beta-carotene and folic acid with the "true intake" (0.65 and 0.65) were higher than the VCs of urinary nitrogen and alpha-tocopherol (0.44 and 0.34, respectively). The DEARR study showed that the newly developed FFQ is a valid and reproducible instrument for assessing dietary intake. The VCs obtained can be used for future adjustment of diet-disease RR estimates in this population.