What do individuals with morbid obesity report as a usual dietary intake? A narrative review of available evidence

Background: In several developed countries, as obesity prevalence doubles it has quadrupled for morbid obesity (BMI ≥ 40 kgm⁻²). As more individuals with morbid obesity present for weight loss treatment there is a greater need to understand their dietary habits. No reviews were found in the literature, therefore this systematic review aims to identify and describe the existing evidence on the usual dietary intake of individuals with morbid obesity including those from a general population and those seeking treatment such as weight loss surgery. Methods: A literature search of ten databases from 1980 to June 2014 was conducted to identify original research of adults with morbid obesity (aged 18–60 years) that reported a usual dietary intake. Results: Ten studies met all inclusion criteria and reported energy intake, most reported macronutrient composition, two assessed micronutrient intake, and one reported food-based outcomes. Other dietary outcomes were related to surgical intervention. The most plausible energy intake data suggest high intakes, >4000 Kcal/day for those weight stable at the highest levels of morbid obesity (up to BMI 97 kgm⁻²). Fat intakes are also high, around 40% of energy intake and up to 57% for some individuals. Suboptimal intakes of iron and calcium are reported. Conclusion: This review draws attention to a limited evidence base, offers preliminary insight suggesting individuals with morbid obesity are prone to consuming poor quality diets similar to those reported for obese populations, and highlights challenges for future research.