CHQ: Post chemo for breast ca.( methotrexate and cytoxin) I gained weight. I had always been a string bean until then. After reading about christensenella I began to wonder what might kill our little friendly gut bacteria. Antibiotics and chemo are so common in our culture. I wondered could this be  causative in the obesity that exists in the USA ?
Summary: Does antibiotic use and chemotherapy cause weight gain?