This comes up on Doctor XM radio from time to time. I found it interesting that doing a stool transplant from an obese person to a thin person will cause the thin person to become obese and never regain their thin body type despite dieting.
Fecal transplants are also used to combat C.Diff in cases where the normal treatment is ineffective.
“Stool transplants” are a real and effective treatment for people who are having certain types of intestinal problems. They are one technique used to help restore a healthy balance of good bacteria in the intestines. But you must realize that what you seem to believe is in the realm of urban legend and not supported by facts.
All food cravings come from the gut bugs too. Changing your diet by force for a while can remove your sugar cravings and have you craving healthy food that helps your gut bugs and then they in turn help your health including moods and clarity of mind etc. By changing your gut population you make a healthy diet easy to stick to. The good gut bacteria love resistant starches found in root vegetables and starchy tubers.
This experiment was done on mice.