In the past 100 years, there have been myriad medical discoveries—giant steps—from Louis Pasteur’s germ theory, to the understanding of gut physiology and metabolic processes—that are the essential underpinnings of modern day medicine. The beginnings of surgery to promote weight loss, now known as bariatric surgery, date back to the 1880s when it was noted that gut resections resulted in weight loss. It was not long afterward that articles started to appear documenting nutritional “disturbances” and the patient’s likelihood of survival based upon the location and the length of bowel removed. Numerous articles have been penned citing the first bariatric surgeries, but to date, there has not been a comprehensive look back at the origins of the science as well as the severe metabolic complications that furthered understanding, prompted innovative medical and surgical approaches, and ultimately led to modern day practice. This article endeavors to do exactly that. Intestinal bypass surgeries to treat obesity are here to stay. Some of the most profound complications of intestinal bypass manifest in the skeleton and include skeletal demineralization, hyperoxaluria, nephrolithiasis, and fractures. Much has been done to further elucidate the underlying mechanisms, identify preventive strategies, and implement practice guidelines, but this patient population remains at increased risk for metabolic bone disease. © 2014, Springer Science+Business Media New York.