All our bodies are different. I also have horses, and since they get more parasites, it's easier to see and monitor.
parasites love sugar, so they make you crave sugar, since this food has not nutrional value, it can do nothing but make you unhealthy and in some people overwieght.
I can tell you in horses, when they are loaded with parasites, they lose muscle tone,(no hind end, bony back, no muscle tone on their shoulder), but end up with a big fat belly. This is because the parasites take all their nutrition and leave only used food for them. Besides the fact that the parasites take their energy and make them lazy.
I'm sure that it makes some people skinny, but remember that muscles burn off calories and if you lost muscle tone because of parasites, it might all go the wrong places. Just my opinion and experience.