Bariatric surgery is a surgical intervention that treats severe cases of obesity. The two kinds of bariatric surgery discussed in the book are the sleeve gastrectomy, which reduces stomach size to a banana, and the gastric bypass, which reduces it to the size of a walnut. Dr. Jastreboff acknowledges that these surgeries are “highly effective” at prompting weight loss and explains that they can now be used in conjunction with obesity medications.

The body and brain’s body fat set point, or the “Enough Point,” as Jastreboff calls it, is the weight that one’s body and brain are accustomed to. While this weight may actually be unhealthy, if a person has been overweight for a long time, their body will have acclimatized to maintaining a certain level of fat storage. When they lose weight, their body and brain will fight to regain it by changing their cues as well as how they maintain one’s energy and fat storage (metabolic adaptation).

These acronyms refer to glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Synthetic versions of these NuSH hormones are the active ingredients in the obesity medications that Jastreboff discusses.

“Metabolic adaptation” refers to people’s changing metabolism. For instance, if a person weighs 200 pounds, their body and brain will acclimatize to this weight, thinking that it’s the ideal amount of fat storage. If they lose 50 pounds, their body will adjust how it burns the energy they’re taking in and signal them to eat more in order to regain their lost weight.

NuSHs are released when people eat food and begin to digest it. These include amylin, glucagon, polypeptide YY, GIP and GLP-1. These hormones help people’s brains register when they have had enough food, creating feelings of satiety. Synthetic versions of these hormones are the active ingredient in obesity medications, helping to lower the body’s Enough Point.