Parasites can have an impact on our weight by causing an imbalance in our system. They steal nutrients and want us to eat their preferred foods. For some, a loss of appetite will occur – and for others, an increase in appetite will occur. With regards to increase in appetite, if the parasites take important nutrients or make it hard for your body to digest these nutrients into your system, you will be lacking them – and the brain can send additional hunger feelings in order to get more of the missing nutrients. Nausea caused by parasites can decrease appetite as well as other gut issues caused by them – ie making it less enticing to eat.