Impact of Simulated Caloric Reduction on Nutrient Adequacy Among U.S. Adults with Overweight or Obesity (National Health and Nutrition Examination Survey [NHANES] 2015-2018).

BACKGROUND

Current guidelines for the treatment of obesity recommend dietary restriction to create a caloric deficit, and caloric reductions of 16% to 68% have been achieved in adults with overweight or obesity engaging in intentional weight loss programs.

OBJECTIVES

This study models the impact of simulated caloric reduction on nutrient adequacy among U.S. adults ≥19 y with overweight or obesity using National Health and Nutrition Examination Survey data (2015-2018).

METHODS

Four levels of caloric reduction (20%, 30%, 40%, and 50%) were modeled by prorating daily calorie intake such that usual intakes of 14 nutrients were reduced proportional to caloric reduction. The percentages below the estimated average requirement (EAR) or above the adequate intake (AI) were estimated at each level of caloric reduction, with and without dietary supplement use. Differences across percentages of simulated caloric reductions were determined using nonoverlapping confidence intervals of the means (97.5 percentile confidence intervals were used to approximate P < 0.05).

RESULTS

There were significant differences (P < 0.05) in percentages below the EAR (above the AI) between sequential levels of simulated caloric reduction for most of the nutrients analyzed (protein, vitamins A, B-6, folate, and C, calcium, iron, magnesium, potassium, and zinc). For example, after a simulated 30% caloric reduction, 25%-40% of the population had intakes below the EAR for protein, vitamin B-6, and zinc, and 75%-91% of the population had intakes below the EAR for vitamin A, calcium, and magnesium (vs. 4%-18% and 45%-56%, respectively, without caloric reduction). With the inclusion of dietary supplements, percentages below the EAR for all nutrients (except protein) were lower than those for food alone.

CONCLUSIONS

Caloric reduction may exacerbate nutrient inadequacies among adults with overweight or obesity. Inclusion of nutrient-dense foods, fortified foods, specially formulated products, and/or dietary supplements should be considered for those on calorie-restricted diets for long-term weight loss.