Purpose: Findings from few studies that investigated the relation between dietary behaviors and obesity are inconsistent. We aimed to assess the relation between patterns of dietary habits, identified by latent class analysis (LCA), and obesity in a large sample of Iranian adults.
Methods: In a cross-sectional study on 7958 adults, dietary behaviors were assessed in five domains (meal patterns, eating rate, intra-meal fluid intake, meal-to-sleep interval, and fatty foods intake) using a pretested questionnaire. LCA was applied to identify classes of diet-related practices. Anthropometric measures were assessed through the use of a validated self-reported questionnaire. General and abdominal obesity were defined as a body mass index ≥ 30 kg/m(2), and a waist circumference ≥ 88 cm for women and ≥ 102 cm for men.
Results: General and abdominal obesity were prevalent in 9.7 and 27.7 % of the study population, respectively. We identified three distinct classes of eating rates (moderate, moderate to slow, and moderate to fast), two classes of meal patterns (regular and irregular), two classes of intra-meal fluid intake (moderate and more intra-meal drinking), three classes of meal-to-sleep interval (short, moderate, and long meal-to-sleep interval), and three classes of fatty food intake (low to moderate, moderate to high, and low intake of fatty foods). After adjustment for potential confounders, individuals with 'irregular meal pattern' were 21, 24, and 22 % more likely to be overweight/obese, abdominally overweight/obese, and abdominally obese, compared with those who had a 'regular meal pattern.' Individuals with 'more intra-meal drinking' had greater odds of overweight (OR 1.37; 1.19-1.458) and obesity (OR 1.51; 1.16-1.97) than those with 'moderate intra-meal drinking.' Moderate-to-high intake of fatty foods was inversely associated with abdominally overweight/obese (OR 0.85; 0.73-1.00) and abdominally obesity (OR 0.80; 0.68-0.96) compared with 'low-to-moderate intake of fatty foods.' No significant association was observed between eating rate, meal-to-sleep interval, and general or abdominal obesity, after controlling for confounders.
Conclusion: Irregular meal pattern and more intra-meal drinking were associated with increased odds of general and abdominal obesity, whereas moderate-to-high intake of fatty foods was related to the decreased odds of central obesity among Iranian adults.
Keywords: Abdominal obesity; Dietary habits; Eating rate; Fatty food intake; Fluid intake; Latent class analysis; Meal regularity; Meal-to-sleep interval; Obesity.