Low-grade inflammation in obesity causes low-effort food choice

Inflammation relates to decreased effortful behaviour and altered effort-related responses in brain regions, such as the dorsomedial prefrontal cortex (dmPFC). Inflammation is prevalent in obesity, but its effects on effortful versus more convenient food choices are unknown. We investigated the role of low-grade inflammation in effortful food choice using functional MRI in a cross-sectional study (n=150 women, BMI>27 kg/m{superscript 2}) and a 12-week randomized controlled trial (n=59 women, BMI>30 kg/m{superscript 2}, CRP>3 mg/L; colchicine 0.5 mg/d vs. placebo). Inflammation was related to less high-effort choices (OR=0.27, p=0.004) and higher effort-related dmPFC signal ({beta}=0.23, p=0.025, Rpartial{superscript 2}=0.039), and mediated the association between BMI and dmPFC signal. Colchicine decreased systemic inflammation (i.e. INFLA-score) as expected ({beta}=-0.10 SD, p<0.001, Rpartial{superscript 2}=0.030), increased high-effort choices (OR=1.32, p=0.044), and marginally decreased effort-related dmPFC signal ({beta}=-0.13, p=0.053, Rpartial{superscript 2}=0.037). These findings show a causal role for inflammation in choosing convenience foods in obesity via increased effort aversion and associated dmPFC processing.