As it turns out, life is more complicated!
Come and listen to a story and think this through again...
https://www.iflscience.com/health-and-medicine/woman-becomes-obese-after-fecal-transplant-overweight-donor/
"While they may sound totally disgusting, fecal transplants are emerging as a promising treatment for a variety of gastrointestinal diseases, in particular infection with the bacteria Clostridium difficile.They don’t quite involve directly inserting the feces of one person into another, but rather the donor stool is rinsed and strained and then introduced into the recipient, either through an enema or endoscopy, or orally in pill form. The idea is to replace healthy bacteria in the gut after the normal balance is disturbed, for example by antibiotics.
One woman suffering recurrent C. difficile infection was recently successfully treated with this procedure, but interestingly, she also rapidly went from normal weight to becoming obese after receiving the transplant. While the weight gain could be due to a variety of factors, the donor was also overweight, and the recipient had never struggled with her weight before. Researchers are therefore speculating whether something in the transplant could have played a role in her weight gain, and have described the intriguing case in Open Forum Infectious Diseases.
At the time, the woman was a healthy 136 pounds with a normal BMI of 26. Her daughter weighed 140 pounds at the time, with a BMI of 26.6, but became overweight shortly afterward. Following the therapy, the woman’s symptoms vanished and she no longer experienced recurrent infections.
Sixteen months later, however, the woman reported unintentional weight gain of 34 pounds and met the criteria for obesity. Two and a half years after the transplant, the woman weighed 177 pounds with a BMI of 34.5, despite a medically supervised liquid protein diet and exercise program.
So to simplify that story, a woman had a C diff infection.
Her (overweight) daughter volunteered to share gut bacteria to replace hers.
Mom's weight exploded.
Hmmmmmmmmm!!
I read the entire article. Nowhere did it indicate she gained weight while consuming less calories than she burned. No matter what (kooky) medical procedure one goes through, it is impossible for someone to gain weight while burning more calories than they consume.