Obesity, orbitofrontal structure and function are associated with food choice: a cross-sectional study

Abstract

Objectives Obesity is on the rise in the US and is linked to the development of type 2 diabetes and cardiovascular disease. Emerging evidence over the last decade suggests that obesity may also adversely affect executive function and brain structure. Although a great deal of research focuses on how diet affects the brain and cognitive performance, no study focuses on how food choice may be associated with brain integrity. Here we investigated how lean and overweight/obese (o/o) adults differed in their food choices and how brain structure and cognition may be associated with those choices. Design As part of an ongoing study on diabetes and the brain, participants had routine blood work and a research MRI, received a battery of neurocognitive tests, and were instructed to keep a 3-day food diary. Results and conclusions The lean group ate more high quality foods and less low quality foods compared to the o/o group. In the o/o group, high quality food choices were associated with orbitofrontal cortex volume. The lean group performed better than the o/o group on neurocognitive measures of executive function, such as the Stroop Interference Test, the Wisconsin Card Sort Test and the Trail Making Test B-A, and on attention and concentration tasks such as the Digit Symbol Substitution Test. Taken together, these preliminary data suggest that in obesity poor food choices may be associated with frontal cognitive impairments that may be the result of, or contribute to, decreases in orbitofrontal cortex volume. Therefore, longitudinal studies are warranted to investigate a causal link between food choice and executive functioning.

Figure 1

Inter-rater reliability for 3-day food diaries. High and low quality food choices were assessed by two independent raters. The inter-class correlation coefficients for the high and low quality food choices were 0.97 and 0.86, respectively.

Figure 2

High and low quality food consumption in lean and overweight/obese (o/o) adults. (A) The total number of high (farm produce, fish, whole grains and nuts) and low (meat, refined carbohydrates, fried food, fast food, junk food and alcohol) quality foods consumed per day was counted. Values represent means±SEM. Values with (*) are significantly different from other groups with the same bar colour, p<0.05. (B) Associations between orbitofrontal cortex (OFC) volumes and high and low quality food consumption for the lean and o/o groups. *p<0.05; **p≤0.01.