Can a test tell me if Wegovy or Zepbound will work for me? With Dr. Andres Acosta of Phenomix
Have you ever wondered why the same weight loss plan can work wonders for one person but barely move the needle for another?
Or why some people respond really well to medications like Wegovy, while others struggle with side effects or see little change? That’s the big question behind precision obesity medicine—and today, we’re diving into it with one of the leading experts in the world.
We’re joined by Dr. Andres Acosta, one of the leading voices in obesity medicine and the pioneer behind the concept of obesity phenotypes. He’s board-certified in internal medicine, gastroenterology, hepatology, obesity medicine, and nutrition. At the Mayo Clinic, he co-directs the Nutrition and Obesity Research Program and leads the Precision Medicine for Obesity program, where his work focuses on matching the right treatment to the right patient with fewer side effects.
His research is backed by the National Institutes of Health, with over 145 peer-reviewed papers published in top journals. His work has been featured in major outlets like The New York Times, TIME, CNN, and NPR. He’s also earned “40 Under 40” recognition and co-founded Genomic Sciences—just a glimpse of his many accomplishments.
So, if you’ve ever felt frustrated with trial-and-error weight loss or wondered if there’s a more scientific way to figure out what will actually work for you, you’re going to want to hear what Dr. Acosta has to share in this episode. Keep reading—you won’t want to miss this.
What Precision Obesity Medicine Really Means
Precision medicine is quickly becoming the standard in many areas of healthcare, and obesity medicine is starting to move in that same direction. The idea is simple: instead of relying on a “one size fits all” approach, treatment is tailored to the individual so it actually works for them.
Think about those commercials for medications like Wegovy. They often mention that the average person lost around 26 pounds, while others lost closer to 45. And, of course, the real question for patients watching is: Which group am I in? Precision medicine is designed to answer that by using data, testing, and personal health characteristics to predict which treatment is most likely to work for each person.
Other fields, like oncology, are already much further ahead. Cancer specialists regularly divide diseases into subtypes and then match treatments to those groups, because not all cancers are the same—just like not all cases of obesity are the same. Historically, physicians have always tried to uncover the “why” behind a symptom. For example, a cough could be allergies, an infection, or asthma, and each one needs a different treatment. Today, with more advanced tools, obesity medicine can finally approach care in the same thoughtful way.
This matters because the trial-and-error method of treatment has limits. With conditions like depression, high blood pressure, and obesity, patients are often prescribed something that might help, and if it doesn’t, they’re told to come back and try another option. While physicians always want the best for their patients, this process can feel frustrating and uncertain. Precision medicine offers a more targeted path—identifying root causes and choosing treatments based on those specific drivers.
Obesity, in particular, has many possible root causes: genetics, environment, biology, and behavior. That’s why one person can respond really well to a new medication while another struggles with side effects or sees minimal results. The same goes for bariatric surgery or even diet changes. Precision obesity medicine says, essentially, “let’s stop assuming one treatment works for everyone and figure out what will actually work for you.”
A great example of this is obesity phenotypes—subgroups that reflect different reasons someone might develop obesity. When this idea was first presented at a medical conference, it immediately resonated with many clinicians. It made sense. Doctors were already spending long hours trying to uncover the “why” behind a patient’s weight challenges, and phenotypes provided a scientific framework to make that process more structured.
Instead of broad generalizations like “this diet works for everyone,” precision obesity medicine acknowledges diversity in patient experiences and matches treatment to the actual cause. It’s about giving the right tool to the right person at the right time.
This is where obesity care is headed. And for many patients, this shift could finally mean moving beyond years of trial and error to finding a solution that truly works.
Understanding Hunger, Satiation, and Satiety
For years, obesity care often meant spending close to an hour digging through patient histories, asking about eating habits, past diets, and how hunger or fullness showed up day to day. It gave us some useful insights, but honestly, it felt more like guesswork than science. What was missing was something more concrete—like the way a chest x-ray can instantly explain the reason behind a cough.
That’s where obesity phenotypes come in. Instead of thinking of obesity as a single condition, phenotypes look at the traits that actually drive energy balance. It’s about how people regulate food intake, how their bodies use energy, and even how emotions influence eating. These ideas have been around in research for decades, but only recently have they started shaping everyday clinical care. And the result? A more structured, science-based way of helping patients, but still with that personal touch.
Back in 2015, we explained how people experience eating differently:
Hunger is the signal: “I want to eat.”
Satiation is the point during a meal when eating slows down and eventually stops.
Satiety is the period after eating when fullness lasts– holding off hunger until the next meal.
These terms often get mixed up. We don’t eat “to satiety”—we eat to satiation, and satiety carries us forward. Recognizing this distinction matters because not everyone experiences these processes the same way.
The Four Energy Balance Phenotypes
One of the biggest breakthroughs in obesity care has been realizing that weight struggles aren’t all the same. For so long, patients were given the same diets, the same advice, and the same treatments, even though their bodies responded in completely different ways. It was frustrating for patients—and honestly, for doctors too—because progress often came down to trial and error. Now, by looking at patterns of hunger, fullness, and metabolism, we can start matching people with the treatments that actually make sense for their biology.
This is where the concept of energy balance phenotypes comes in. Think of it as a way to better understand the “why” behind weight gain, rather than treating everyone as if they’re dealing with the same thing.
The four main phenotypes are:
Hungry Brain (Abnormal Satiation): Feeling full takes longer than usual. Big portions or going back for seconds (or thirds) are super common here.
Hungry Gut (Abnormal Satiety): Fullness fades really quickly—sometimes in just an hour. This is often linked to gut hormones like GLP-1. That’s why medications such as Zepbound and Wegovy can work especially well for people in this group.
Emotional Hunger: Eating isn’t always about hunger—it’s triggered by stress, emotions, or even habits. This is the classic “snacking when stressed” or eating to celebrate.
Slow Burn (Low Energy Expenditure): A slower metabolism makes it tougher to burn calories, so losing weight can feel extra challenging even if food intake isn’t that high.
It’s important to note that none of these patterns are “bad” or “abnormal” in a negative sense. They’re just different biological pathways. Framing it this way helps patients see that their challenges aren’t personal failings—they’re rooted in biology. And once you understand your phenotype, the path forward gets so much clearer.
Beyond Energy Balance
Energy balance phenotypes are a huge step forward, but they’re not the whole picture. Obesity is complex, and there are other phenotypes that can shape how someone’s body responds to food, activity, and treatment. These include things like metabolic status (for example, insulin resistance), where the body handles sugar and insulin differently; fat distribution, which is basically whether someone tends to carry more weight in the belly area versus the hips and thighs; and even genetic causes, like rare forms of monogenic obesity.
Still, energy balance phenotypes give us such a practical starting point. They help explain why two people can follow the exact same plan—same diet, same exercise—and yet their results turn out completely different. It’s not about effort or willpower; it’s about how each body is wired.
One of the trickiest parts of obesity care is figuring out what’s really going on, because biology and behavior are so closely tied together. Like, did someone grab a snack because their body was genuinely hungry, or because they were stressed after a long day? Did they go back for seconds because their fullness signals weren’t working, or because they were just having a good time celebrating? Even for patients themselves, it’s not always clear.
That’s why moving toward more objective tools feels so important. If we can actually measure biology, behavior, and genetics, then we can start to separate the “why” behind weight gain in a way that feels less confusing and more concrete.
This is where obesity phenotypes make such a difference. Instead of sticking with trial and error, doctors can match treatments to what’s really driving someone’s weight gain. And that shift? It’s not just about advancing science. It makes care feel more personal, more practical, and honestly, way more encouraging for people who’ve been struggling for years.
Thinking about trying the PhenoTest to see if it could help guide your obesity treatment?
The process is actually super simple. Here’s how it works: the test is offered through Phenomix Sciences, and you’ve got two ways to start. You can either ask your doctor (or another prescriber) to order it, or you can kick things off online—but a medical professional still has to be part of the process.
Once a licensed medical professional, like a doctor or nurse practitioner, places the order, the kit can be shipped to your home or to the clinic. Collecting the sample is quick and easy, and when it’s done, the results go to both you and your doctor. That way, the findings are explained in a medical context, and you get guidance on what steps to take next.
Just a reminder, it’s not a direct-to-consumer product. It’s designed so you and your clinician can work together, making sure the treatment plan is personalized and medically sound.
So that’s the heart of precision obesity medicine—it’s about moving past trial and error and finally finding answers that fit each person’s biology. If this conversation has you curious to learn more, don’t miss the latest episode of the podcast. Dr. Acosta and I go even deeper into how phenotypes and testing can change the future of obesity care. Go give it a listen—you’ll come away with a whole new perspective on what personalized treatment can really look like.
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