Background: Longitudinal studies have shown significant dose-response associations between dietary share of ultraprocessed foods and the incidence of several noncommunicable diseases and all-cause mortality. Several attributes of ultraprocessed foods are potential mechanisms for their link with health outcomes, including their typically unbalanced nutrient profile, high glycemic loads, high energy intake rate, and the presence of food additives, neoformed substances, and substances released by synthetic packaging materials. However, no studies have assessed the plausibility of reduced water intake as an additional association of diets rich in ultraprocessed foods.

Objective: To assess the association between ultraprocessed food consumption and total water intake.

Design: This cross-sectional secondary analysis used data from the National Health and Nutrition Examination Survey, cycles 2011 to 2016, in the United States.

Participants/settings: This study included 24,505 participants aged ≥1 year who completed the first 24-hour dietary recall interview.

Main outcomes measures: The main outcome evaluated was the mean of total water intake.

Statistical analysis: Crude and adjusted linear regressions were applied to investigate the association between quintiles of the dietary share of ultraprocessed foods and the total water intake.

Results: A significant linear reduction in the daily mean total water intake was observed across ultraprocessed food quintiles, amounting to 706 mL between the lower and the upper quintiles. Important increases across quintiles were observed for the intake of sugar-sweetened and artificially sweetened drinks, whereas important reductions occurred for unsweetened drinks, plain water, and water present in solid foods and dishes.

Conclusions: Reduced total water intake and an imbalance between sources of water that favors energy-dense and nutrient-poor sources were associated with increased consumption of ultraprocessed food, suggesting that decreased total water consumption might be a negative outcome of diets rich in ultraprocessed foods. This relationship should be further investigated in longitudinal or clinical trials.