A Functional Approach to Obesity
By Jamie Bussin, featuring Dr. Aaron Hartman MD
Regular readers know my story (perhaps a little too well). A little over twenty years ago I lost 53 pounds — a change that altered everything for me. But I also know this: keeping weight off is a lifelong project. There are ebbs and flows. For a lot of people, it’s not just willpower. That’s why I asked Dr. Aaron Hartman — a physician who pivoted into functional medicine after a deeply personal family crisis — to come on the show and walk me through a more nuanced view of obesity. We spoke about the 5 factors that drive obesity this past weekend on Episode #411 of The Tonic Talk Show/Podcast. This is a digest of that conversation.
Obesity is usually conceived as a single, simple problem. However, a 2022 study out of Manchester argues what many functional clinicians already suspect: there isn’t one type of obesity, there are five — each shaped by genetics, environment, and lifestyle. Historically, medicine concentrated on what Dr. Hartman calls “type 1” obesity — essentially a calorie-in/calorie-out model. That worked when our environments were different. But today, with chemical exposures, processed food, and chronic inflammation, the old model often fails.
For example, some people gain weight primarily from emotional or stress-related eating. I related to this. My own weight loss journey included confronting anxiety-driven habits: when stress rises, so does my appetite for comfort food. Dr. Hartman explains why emotional eating is so persistent: the brain’s dopamine system. Certain foods — especially sugar and highly palatable processed foods — trigger dopamine spikes that reinforce eating behaviour. Over time, those hit-and-repeat cycles become hardwired. Medications can sometimes help (drugs approved for binge eating and antidepressants such as bupropion), but the real cure is rewiring the brain: behavioural therapy, changing thought patterns, and restructuring one’s relationship with food.
Then there are the people whose weight is primarily diet-driven — not emotional craving, but simply decades of ultra-processed foods. Dr. Hartman is blunt: seed oils, rancid fats, and nutrient-poor boxed foods have transformed our metabolic landscape. He points out that much of the meat in the U.S. food supply is produced with routine antibiotics, and those practices — along with processed cooking oils — can drive low-grade inflammation and metabolic disruption. The result? Diet alone no longer behaves the same way it used to. You can change calories and still be fighting inflammation, endocrine disruption, and microbial imbalances.
Lifestyle factors are the third big bucket. Sitting is the new smoking, as the saying goes. From our mid-20s forward we naturally lose muscle — roughly 1% a year — and gain fat. Muscle is metabolically active and produces myokines, hormones that help regulate metabolism. Lose muscle and your resting calorie burn drops, making weight maintenance much harder. Movement isn’t just about burning calories; it keeps the tissues and hormone systems functioning.
Hormonal and environmental causes form the fourth group. “Obesogens” are chemicals in our environment that act as endocrine disruptors, altering hormone signaling and promoting fat storage. These toxins, which can accumulate in fat tissue, help explain why certain people (often women) struggle more with weight despite reasonable diets: the body is literally holding onto pollutants as a protective measure. Removing exposure and supporting detoxification can be part of a treatment plan.
Finally, genetics plays a role — not moral failing, but biological predisposition. Some populations are more vulnerable to weight gain in our modern food environment. Certain ethnic groups — Latino and Indigenous populations, for instance — have higher susceptibility in our current context, a legacy of complex interactions between genes, historical diets, and modern processed foods.
What struck me most in our conversation was how rarely one single factor explains someone’s weight. Dr. Hartman describes a layered, methodical approach: identify which of the drivers are most relevant to a patient, treat them one by one, and expect this to be slow and steady work. He’s had patients who need a year or two simply to step through the different issues — inflammation, gut health, neural wiring, detox, sleep, and trauma — before they start seeing consistent change.
A few practical takeaways came through loud and clear:
- Address dopamine and behaviour: If eating is a coping mechanism, it’s not enough to bluster your way through. You need behavioural strategies, sometimes medication, and a re-training of reward pathways.
- Clean up the diet beyond calories: Prioritize whole foods, minimize ultra-processed products and seed oils, and be mindful of antibiotic residues and food system realities.
- Move to maintain muscle: Resistance work and regular activity preserve muscle mass and metabolic health. That’s particularly vital as we hit our 40s and 50s.
- Consider environmental toxins: For some patients, lowering exposures and supporting detox pathways (under clinical guidance) can improve hormone balance and facilitate weight loss.
- Be patient and precise: This isn’t a quick fix. For many people, the path forward is iterative and individualized.
We also touched on the modern context of dopamine addiction — not just food, but screens and tech. Dr. Hartman referenced the idea that we live in a “dopamine nation,” where constant small rewards (notifications, likes, sugar hits) train our brains toward short-term gratification. For those with trauma histories, food becomes a powerful, tangible way to soothe an invisible wound. In those cases, working through trauma isn’t optional — it’s central to recovery.
If there’s one message to take away, it’s this: obesity in 2025 is rarely just about calories. It’s a metabolic, neurologic, hormonal, and toxicological puzzle that must be solved piece by piece. That doesn’t remove responsibility — people still need to eat better and move more — but it reframes the conversation from blame to strategy. It offers hope to those who’ve been told that nothing more can be done.
I left our conversation encouraged and realistic. Change is possible, but it’s nuanced and often slow. For anyone struggling with weight, the smartest first step is a careful assessment that looks beyond the scale. Because when you address the root causes — not just the symptoms — you can actually reclaim your life.
