These days, it's hard to avoid the constant barrage of advertisements for the "GLP-1" medications, most notably Ozempic and Wegovy, the two most popular brands. Originally developed as diabetes treatments, recently it was shown that they can be effective weight loss therapies as well.
These drugs increase the body's level of a hormone known as GLP-1. Hormones are the messengers of our bodies, helping to communicate what is happening and coordinating actions across body parts. GLP-1 in particular is responsible for communicating appetite, or lack thereof: When food arrives in the stomach, GLP-1 is generated to tell the pancreas to make more insulin, and also to tell the brain that food has been eaten so that it stops trying to find (and consume) more food. More GLP-1 means less hunger; medicines that help the body make and use GLP-1 more effectively can lead to less overeating and cravings.
Adoption of GLP-1 medications happened fast, in part because they aren't new drugs: They were already on the market as diabetes treatments, which meant they had already run the gauntlet of Food and Drug Administration (FDA) safety tests and approvals. But a rapid rollout like this leaves many questions unanswered: Who is it being prescribed for, are the effects short-term or long-lasting for them, and what kind of change does it have on the foods they buy and eat? This weekend's read is a new research report that attempts to answer those questions. Two researchers from Cornell University and a data scientist from market research company Numerator crunched the numbers from 150,000 U.S. households that Numerator surveys, using data gathered from July 2022 to October 2024.
As of July 2024, 11.6% of the households surveyed had at least one member using a GLP-1 medication or who had previously used one. Interestingly, the number of people using the meds for weight loss is growing faster than those using it for its original purpose, diabetes treatment, and since late 2023, there have been more people using it for weight loss than for diabetes.
There are also some interesting demographic differences. Among people under age 55, the majority are using the medications for weight loss; while those 55 and above mainly use them for diabetes. Also, weight loss users tend to have higher incomes.
Interestingly, though, people lost about the same weight regardless of their goal.
Given their higher incomes, it's probably not surprising that about one-fourth of those using GLP-1 medications for weight loss are paying for it out of pocket, whereas those using it for diabetes are more reliant on insurance (private or Medicare/Medicaid).
The researchers then turned their attention to the GLP-1 med users' food purchases. They found that households with at least one GLP-1 med user saw a gradual decline in grocery purchases over the first six months after the medicine was prescribed. Higher-income households (above $125,000 annually) saw a bigger decline, on average 8.6%, saving about $690 over a year. Lower-income households saw an average decline of 4.2% and savings of $240 annually.
Both groups — weight loss and diabetes — decreased their purchases across a broad set of products; in fact, the only purchases that went up were fresh produce and yogurt, and then only for weight loss users. As the researchers put it, "the composition of their grocery baskets becomes healthier more by cutting back on unhealthy items than by adding more healthy ones."
Both groups also cut back on eating out, though there was another curious income-related difference: Higher-income households decreased their spending during breakfast, while lower-income households decreased spending on dinner.
On to the next question: Do the changes stick? The researchers found that in the period between six and 12 months after starting the GLP-1 medication, the effect "faded" a bit: The size of the spending reduction decreased. Put another way, food expenditures started going back up again — though still below what they were before they started the medication. This was true for both groceries and dining out.
As with all good research reports, this one finally turns to "what does this all mean?" And interestingly, the researchers (two of whom work in Cornell's business school) chose to adopt the perspective of stakeholders in the food industry, pointing out that broad-based reductions in household food expenditures have implications for grocery chains, restaurants, and the businesses that grow and make food. Some food companies have already reported declines in sales over the past year. Moving forward, they will need to decide how to respond, including whether to adjust ingredients and recipes, decrease portion sizes, or change packaging strategies if people are purchasing and consuming less food — especially unhealthy food.
The study leaves some big questions unanswered. One is the classic issue of "causation versus correlation": Is food consumption going down because of the GLP-1 medication (a reasonable hypothesis given what the medication does), or is the decrease in food purchases a conscious switch to healthier eating that went hand in hand with a decision to start taking medication to control diabetes or lose weight? Though even if it is the latter, having a decreased appetite might make it easier to sustain those healthier eating decisions.
Also, the data doesn't give us a completely clear picture of what's happening, because it tells us about the combined food purchases for everyone who lives in a household and not just the person taking the GLP-1 meds. Is everyone in the household eating less, or is it just the person taking the medication?
In addition, the study only looks at the first 12 months, largely because that is all the data that is available at this time, since the tidal wave of GLP-1 medication adoption is so recent. In another 12 months, will food purchases in the households go back to what they were before, or will this establish a "new normal"? On a related note, we don't know how long people will take the GLP-1 medications to lose weight or whether they will be able to sustain the weight loss once they stop taking the meds.
Finally, the researchers point out that the profile of people who are using GLP-1 medications to lose weight will continue to evolve as their effectiveness becomes better understood, and we have no way to predict how the larger pattern of food consumption in the United States will evolve with that profile.
It is, however, exciting to see that the GLP-1 medications aren't just being used to try to burn off fat: People taking them are actively opting for healthier eating habits.
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