The cerebral activity associated with attentional processes may differ between individuals with different weight statuses in the presence of food stimuli (e.g. odours, pictures). The objective of the present study was to test the influence of non-attentively perceived food odours on the cerebral activity underlying the processing of food pictures, in normal-weight, overweight, and obese adults. To do so, we used an implicit olfactory priming paradigm with a pear odour and a pound cake odour as primes, respectively priming sweet low-energy-density foods and sweet high-energy-density foods. Event-related potentials were recorded while the participants passively watched pictures of sweet low- and high-energy-density foods, under the two priming conditions plus an odourless control condition. The amplitude of the P100 and the P200 peaks were measured. The results suggest that the cerebral activity underlying the processing of food cues differs depending on weight status, from early and non-conscious stages of attentional processing.