How GLP-1s change appetite biology

For decades, obesity was treated as a matter of self-control and free will: If you were fat, it was your own fault.

You could try a diet - but the diet companies were also in on the fix: For years, Weight Watchers was owned by Heinz food … and Jenny Craig was owned by Nestle. 

But it was still up to you. You made your choices, and you had to live with them. And so the obesity rate in the US soared from around 15% of the population in 1970 to more than 40% today. Clearly something is going on other than free will and personal choices.

In this episode of Drug Story, we explore the origins of the obesity epidemic: the Green Revolution in agriculture, which saved a billion lives, but also made grain cheap cheap cheap. And we look at what happened when the tobacco companies decided to diversify into the food business (surprise: food became a lot more addictive, and a lot less healthy). 

And we re-consider the whole idea of personal freedom and free will.

This episode's drug is Ozempic, and the whole class of GLP-1s that have up-ended our presumptions around obesity. These drugs have transformed millions of lives - they are surely one of the most impactful medical discoveries of the century. 

Unfortunately, these drugs have not dispelled the stigma around obesity. They’ve just shifted it a bit. If you think taking a GLP-1 is “cheating,” you’re still stuck in the old blame game.

Sources for this episode

[1] KFF Health Tracking Poll May 2024: The Public’s Use and Views of GLP-1 Drugs (2024) KFF: KFF poll showing awareness, perceptions, and use of Ozempic, Wegovy, and similar medications in the U.S.

[2] Norman Borlaug Man Of The Year 1969 (2011) The International Maize and Wheat Improvement Center: Norman Borlaug introducing himself as a man who grew up during the Great Depression and was raised on a farm in Iowa. 

[3] Norman Borlaug and the Green Revolution (2017) 20th Century Time Machine: Norman Borlaug created a high-yield wheat strain that transformed the agricultural industry and saved an estimated one billion lives. Considered the father of the Green Revolution, he was awarded the Nobel Peace Prize in 1970.

[4] Chapter 1 | The Man Who Tried to Feed the World (2020) American Experience PBS: Norman Borlaug, inspired by his own upbringing in struggling Iowa, helped the world avoid famine and hunger through revolutionizing wheat production.

[5] Food Timeline FAQs: historic food prices (2024) Food Timeline: In addition to increasing the supply of food globally, the Green Revolution also made food much more affordable.

[6] What Is the Evidence for “Food Addiction?” A Systematic Review (2018) Nutrients: A systematic review of 52 studies concludes that food addiction is a valid diagnostic construct that is more similar to substance use disorder than behavioral addiction, especially among processed foods with added sweeteners and fats.

[7] The Origins of the Obesity Epidemic in the USA–Lessons for Today (2022) Nutrients: The origins of obesity can be traced back to the introduction of ultra-processed food in the American diet. 

[8] US obesity rates have tripled over the last 60 years (2025) USA Facts: American rates of obesity have tripled since the 1960s, with over 40% of Americans having obesity.

[9] Daily supply of calories per person (2025) Our World in Data: From 1970 to 2020, Americans increased their daily calorie intake from about 3,000 to over 3,800 calories.

[10] US tobacco companies selectively disseminated hyper-palatable foods into the US food system: Empirical evidence and current implications (2024) Addiction: In a study reviewing industry documents and U.S. Department of Agriculture data from 1988 to 2002, food produced U.S. Tobacco companies that owned food companies were 80% more likely to be high in carbs and sodium than other foods.

[11] Many of today’s unhealthy foods were brought to you by Big Tobacco (2023) University of Michigan Department of Psychology: Research shows how major tobacco companies exerted their influence on the American diet by applying their expertise in chemical dependency to the food industry.

[12] Ultra-processed Food Consumption in Youth and Adults: United States, August 2021–August 2023 (2025) CDC: According to the CDC, ultra-processed foods are hyperpalatable, high in sodium, and low in fiber, like sandwiches, sweet bakery products, and sweetened beverages.

[13] Highly processed foods can be considered addictive substances based on established scientific criteria (2022) Addiction: Using the same scientific criteria the U.S. Surgeon General employed in 1988 to identify tobacco as addictive, this analysis suggests that highly processed foods, rich in refined carbs and added fats, should be considered addictive.

[14] Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake (2019) Cell Metabolism: In a randomized control trial, researchers discovered that participants on an ultra-processed diet voluntarily consumed about 500 extra calories per day. The study concludes that people gain weight on ultra-processed diets and lose weight on unprocessed ones.

[15] Cereal, pasta, and other food companies blast the FDA for a too-strict definition of ‘healthy’ (2023) STAT: The FDA has posed new rules on what can be considered “healthy” for a food product, limiting added sugar, sodium, and saturated fats. Industry giants argue that these rules are overly restrictive and food will be less palatable to consumers if less sugar and salt is in food.

[16] Adult obesity rates rise in 6 states, exceed 35% in 7 (2018) American Medical Association: The American Medical Association reports that adult obesity rates in the United States have reached historic highs, now affecting nearly 40 percent of the population.

[17] Recognition of Obesity as a Disease H-440.842 (2023) American Medical Association: The American Medical Association recognized obesity as a disease in 2013.

[18] Obesity as a Disease: Has the AMA resolution had an impact on how physicians view obesity? (2016) Surgery for Obesity and Related Diseases: Even after obesity was classified as a disease in 2013, many providers remained unaware of the resolution or held conflicting views on its validity, and debated whether obesity is a primary pathology or merely a behavioral risk factor.

[19] The Story of GLP-1: Episode 4 - "The next really good idea". (2022) Novo Nordisk Foundation: Novo Nordisk executives convinced their CEO that obesity should be treated as a medical challenge rather than a cosmetic issue. 

[20] What the Scientists Who Pioneered Weight-Loss Drugs Want You to Know (2023) WIRED: Interview with Jens Holst and Joel Habener, pioneers of GLP-1 research and early development of this drug class.

[21] We Know Where New Weight Loss Drugs Came From, but Not Why They Work (2023) The New York Times: This article discusses unknowns in GLP-1 mechanism of action, their effects on brain hormone levels, and the reframing of obesity as a biological rather than moral condition.

[22] The Ozempic Era Could Shift Blame for Obesity From Individuals to Commercial Food Systems (2025) Issues in Science and Technology: Given GLP-1’s mechanism of action, which targets biological pathways in the brain, obesity can be understood as a consequence of ultra-processed foods and an industrialized food system rather than a failure of individual willpower; the authors draw parallels to the alcohol and tobacco industries.

[23] Jim Gaffigan's Laughs Through His Weight-Loss Journey | Hulu (2025) Hulu: Jim Gaffigan addresses the stigma of using weight-loss drugs, highlighting how critics accuse him of "cheating" while he views the medication as a necessary tool for a "guy trying to not die".

[24] PEP Stock | PepsiCo Inc. Q1 2025 Earnings Call (2025) AlphaStreet: In a 2025 earnings call, the CEO of PepsiCo reports on the need to manage and adapt to recent health trends, including the rise and adoption of GLP-1s, which have resulted in customers eating smaller portions.