Intakes of plain water, moisture in foods and beverages, and total water in the adult US population--nutritional, meal pattern, and body weight correlates: National Health and Nutrition Examination Surveys 1999-2006.

Background: There is a surprising paucity of studies that have systematically examined the correlates of water intake in the US population.

Objective: The objective was to examine the association of contributors of water intake with dietary characteristics, meal consumption, and body weight in the US population.

Design: We used 24-h dietary recall data from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 (n = 12,283) and the NHANES 2005-2006 (n = 4112) to examine the independent association of intakes of plain water, beverage moisture, food moisture, and total water with sociodemographic factors, dietary characteristics (energy, nutrients, diet quality, and energy density), and meal patterns (number of eating episodes, mention of breakfast or snack) by using multiple regression methods.

Results: In 2005-2006, American adults reported consuming 3.18 L of total water within the previous 24 h (in 1999-2004, estimated total water intake was 3.35 L), with plain water and beverages contributing 33% and 48% of the total, respectively. Plain water intake was unrelated to the intake of energy and body mass index but was positively related to dietary fiber and inversely related to beverages, sugars, and the energy density of foods; these associations were in the opposite direction for beverage moisture intake. Total water intake was inversely related to energy from fat and energy density but positively related to dietary fiber, caffeine, alcohol, and diet quality. The number of eating episodes predicted higher beverage and food moisture and total water intakes. A higher body mass index predicted higher intakes of beverage moisture and total water.

Conclusion: Various contributors of total water intake differed in their association with dietary characteristics and body weight in the adult US population.