Obesity is a disease that has serious physical, psychological, and economic implications for patients and the health care system.1
When defined by a body mass index (BMI) of 30 kg per m2
and above, 42% of the current U.S. adult population have obesity, and 9% have class 3 obesity (BMI greater than or equal to 40 kg per m2
The primary care office can be a supportive, nonjudgmental environment for patients with obesity by connecting them with evidence-based treatment resources. The Strategies to Overcome & Prevent (STOP) Obesity Alliance (https://stop.publichealth.gwu.edu
) provides resources for physicians,3
and the Obesity Action Coalition (https://www.obesityaction.org
) provides resources for patients and physicians.4
On average, patients who have metabolic surgery lose 26 kg (57 lb) more than those with nonsurgical weight loss and are five times more likely to experience remission of diabetes mellitus.5
According to the American Society for Metabolic and Bariatric Surgery, approximately 256,000 metabolic surgeries were performed in the United States in 2019, a 32% increase in five years.6
The term metabolic surgery is now preferred because of the metabolic effects of surgical procedures beyond weight loss.7
What Procedures Are Commonly Performed?
The sleeve gastrectomy procedure resects most of the body and all of the fundus of the stomach, creating a long, narrow, tubular stomach (Figure 18). Single anastomosis duodenal-ileal bypass with sleeve was endorsed by the American Society for Metabolic and Bariatric Surgery in 2020 and will likely become more prevalent in the coming years.9 Single anastomosis duodenal-ileal bypass with sleeve adds a bypass of the duodenum to traditional sleeve, which can be performed as a single procedure or as a revision to a prior sleeve gastrectomy (Figure 2).
In Roux-en-Y gastric bypass, a small gastric pouch is formed by dividing the upper stomach and joining it with the resected end of the jejunum so that food bypasses the stomach and upper small bowel, thereby restricting the size of the stomach and causing some malabsorption (Figure 38).
Family physicians may see patients who have a laparoscopic adjustable gastric band (Figure 48). The adjustable gastric band now accounts for less than 1% of procedures because of a higher complication rate and lesser weight loss.6,10
How Does Metabolic Surgery Lead to Weight Loss and Improvement in Type 2 Diabetes?
Procedures were previously conceptualized as restrictive (create a smaller stomach), malabsorptive (bypass normal anatomy), or a combination, resulting in a calorie deficit. However, improvements in blood glucose levels and other obesity-related conditions occur earlier than can be fully explained by weight loss. Research indicates that the mechanisms of action include multiple physiologic variables that impact a complex neuroendocrine system involving the gut, central and peripheral nervous systems, and adipocytes to regulate energy homeostasis.11
Glucagon-like peptide-1 and peptide YY increase after Roux-en-Y gastric bypass and sleeve gastrectomy.11
Glucagon-like peptide-1 enhances insulin secretion, whereas peptide YY increases satiety and delays gastric emptying. Other hormones affected by metabolic surgery include insulin, ghrelin, leptin, C-reactive protein, interleukin-6, tumor necrosis factor–alpha, and adiponectin.11,12