Is obesity a new phenomenon? How was it historically managed? And what’s behind the new medications for weight loss?
In ancient times, obesity was rarely an issue. In fact, throughout much of history and in many societies, being overweight was a sign of prosperity, as it signaled access to food that was primarily restricted to the elites. This view persists, up until today, in some communities in
Mauritania,
where a female beauty is determined by higher weight. Throughout history, having low weight was often viewed negatively, as an indication of poverty, illness, or both. But what about the new world?
In the new world,
obesity remained a rarity even in the late nineteenth century. Chauncey Morlan, reported to be the "world's fattest man" in 1890, weighed 875 pounds (397 kg) at his heaviest, and traveled with a circus as a human attraction. He was introduced as the "Human Freight Car," drawing audiences from across the country who came specifically to see him.
We knew the health risks associated with overeating for thousands of years.
Prophets
spoke of the virtue of eating in moderation. Hippocrates, the father of medicine,
acknowledged
the health risks of being obese and recommended moderation in food intake and regular exercise.
However, when moderation and exercise failed, we resorted to invasive methods. Historical accounts suggest that the earliest form of invasive intervention to induce weight loss occurred in
10th-century Spain.
King Sancho of Leon, known as Sancho the Fat, a reference to his extreme obesity, which hindered his mobility and ability to rule, lost his throne as a result.
In pursuit of treatment, he was taken by his grandmother to Cordoba to visit the physician Hasdai Ibn Shaprut. Ibn Shaprut stitched the king’s lips, restricting him to a liquid diet delivered through a straw. Remarkably, King Sancho shed half his body weight, enabling him to return to Leon, ride a horse again, and reclaim his throne.
In the early 20th century, as medical science advanced, a more scientific approach to understanding and managing obesity started to emerge. We began to understand concepts of
calorie counting
and
energy balance.
In parallel, the mid to late 20th century saw a significant increase in obesity rates, propelled by increased consumption of high-fat, sugar-rich, processed foods, leading to more focused research on obesity management.
This period witnessed the advent of modern surgical approaches to induce weight loss. The first modern metabolic surgery, known as the jejunoileal bypass, was introduced by
Kremen in 1954.
This surgery involves connecting the upper part of the small intestine (jejunum) directly to its lower part (ileum), skipping a large section of the intestine that absorbs nutrients. Instead of stitching the mouth shut—as practiced a millennium ago by Ibn Sharput to reduce food intake—modern surgeons bypass nutrient-absorbing segments of the gastrointestinal tract, a strategy that can lead to malnutrition and, in some cases, surgery-related complications and death due to the invasive nature of the procedure.
Traditionally, Body Mass Index (BMI) is the metric used to determine if someone is obese.
BMI is calculated
by dividing a person's weight in kilograms by their height in meters squared.
However, BMI is limited for personalized intervention, despite its importance as a statistical tool. For example, consider a bodybuilder who weighs 120 kg, has a body fat percentage of 5%, and is 170 cm tall; his BMI is 41.5, and under BMI criteria, this individual would be classified as morbidly obese. This example highlights why BMI alone may not always be the best measure of obesity, given the
'fat but fit'
phenomenon.
Nowadays, obesity is increasingly recognized as a disease. According to the
World Obesity Federation,
obesity is recognized as a chronic, relapsing, progressive disease. However, this definition is not universally accepted, indicating ongoing debates in the medical community about how best to define and understand obesity.
In an effort to define obesity, the 2020 Canadian Clinical Practice Guidelines for adults state: "Obesity is a prevalent, complex, progressive, and relapsing chronic disease characterized by the presence of excess or abnormal body fat (adiposity) that impairs health". The key point is the increase in
abnormal fat tissue that impairs health.
Regardless of the ongoing debate around its definition, obesity is primarily regarded as a
preventable global pandemic
at the population level with complex etiologies, including genetic, environmental, psychological, and social factors.
As such, to tackle the global pandemic of obesity, several medications were developed to induce weight loss, reflecting the challenge between ensuring safety and efficacy. For example, in the 1990s, the fenfluramine and phentermine (fen-phen) combination was popular but withdrawn due to heart risks. Sibutramine was U.S. Food and Drug Administration (FDA)-approved but withdrawn in 2010 for heart risks. Ephedra, causing heart problems, was banned. Rimonabant was initially approved in Europe but withdrawn due to psychiatric risks and was never FDA-approved. Consequently, orlistat, an inhibitor of intestinal fat absorption, remained for many years the only long-term pharmacological option for obesity.
Since 2005, however, we have new players in the game. The first Glucagon-like Peptide-1 (GLP-1 agonist) used for diabetes management
Exenatide was approved by the FDA in 2005.
While initially developed for type 2 diabetes, GLP-1 agonists' role in weight loss was observed, leading to further investigation of their obesity management and subsequent FDA approvals of additional GLP-1 agonists indicated explicitly for chronic weight management, such as
liraglutide (approved 2014)
and
semaglutide (approved 2021),
as well as dual GLP-1/GIP agonist
tirzepatide for obesity (approved in 2023),
and most recently an
oral semaglutide (approved in 2025) for weight loss.
GLP-1 agonists work by mimicking the natural glucagon-like peptide-1 hormone in the body. They promote insulin secretion in a glucose-dependent manner, enhancing blood sugar control. Additionally, they slow gastric emptying, leading to prolonged feelings of fullness, and directly act on the brain to reduce appetite. This dual effect on both glucose metabolism and appetite regulation makes them effective for both diabetes and obesity management.
Emerging evidence
suggests that their positive effects extend to reducing inflammation and protecting the brain.
These medications are changing the way we are approaching metabolic disorders, however, they have some serious side effects, most commonly gastrointestinal adverse effects. For example,
a retrospective observational study
found increased risks of pancreatitis (pancreas inflammation), gastroparesis (paralysis of the gut), and bowel obstruction with GLP-1 agonists.
Our understanding of metabolic disorders including
obesity is evolving
and as we are entering the era of
artificial intelligence
we might finally not only manage chronic medical disorders but cure them. Until then at the individual level, obesity often behaves as a chronic, relapsing condition for which lifestyle interventions alone may be insufficient. In such cases, pharmacotherapy can serve as an evidence-based adjunct to lifestyle modification, initiated under medical supervision in appropriately selected patients.
Disclaimer: This is for educational purposes only and does not constitute medical advice. Always consult your treating physician.