Is the link between depressed mood and heart rate variability explained by disinhibited eating and diet?

•Associations between mood and HRV have been reported previously.•To date no study has controlled for the influence of diet.•We considered whether the link between mood and HRV is explained by poor diet.•The mood − HRV association was serially mediated by disinhibited eating and diet.•Future studies connecting mood and HRV should consider dietary influences.

Consistently it has been reported that a depressed mood and low heart rate variability (HRV) are linked. However, studies have not considered that the association might be explained by dietary behaviour. The resting inter-beat interval data of 266 adults (Study 1: 156 (51 M), Study 2: 112 (38 M)) were recorded for six minutes and quantified using linear (HF power: 0.15-0.4 Hz) and nonlinear indices (Sample entropy). Participants also completed the Profile of Mood States and the Three Factor Eating questionnaires. The Alternative Healthy Eating Index was used to quantify diet quality. In study 1 mood was associated with HRV; an effect partially mediated by diet. Study 2 replicated the finding: disinhibited eating (the tendency to lose control over one's eating) and diet sequentially mediated the association between mood and HRV. Diet plays a role in the link between mood and HRV and studies should consider the influence of this factor.