A review of the scientific literature on Parkinson’s disease shows that even the non-motor symptoms associated with the disease can contribute to the changes in body weight seen in patients (including those subjected to deep brain stimulation). Among the factors affecting eating habits and body weight there could be, for example, an impaired ability to derive pleasure from food and changes in motivation. These are important findings which can help to understand how to reduce these effects of Parkinson’s that exacerbate an already negative clinical situation.