Obesity: Disease or Lifestyle Choice?

As a practitioner who works closely with families navigating weight and health challenges, I’m often asked about the ongoing debate surrounding obesity: Is it truly a disease, or is it simply the result of lifestyle choices? This question has taken on new dimensions in 2025, with groundbreaking research reshaping how we understand and approach this complex condition.

The Medical Landscape Has Shifted

In January 2025, a landmark commission published new diagnostic criteria for what they now term “clinical obesity” in The Lancet Diabetes & Endocrinology. This represents a significant evolution from the American Medical Association’s 2013 decision to classify obesity as a disease. Rather than relying solely on BMI measurements, the new approach focuses on how excess weight actually affects organ function and overall health.

This shift matters because it moves us away from judging bodies based on numbers alone, toward understanding obesity as a condition that can genuinely impact how our bodies function. It’s like the difference between looking at a car’s speedometer versus checking whether the engine is actually running smoothly.

The statistics paint a sobering picture of where we stand globally. According to the World Health Organization’s 2025 data, 43% of adults worldwide are now overweight, with 16% living with obesity. Even more concerning, over 390 million children and adolescents aged 5-19 years were overweight in 2022, including 160 million who were living with obesity.

Here in Australia, we’re not immune to these trends. Our rates have been steadily climbing, and the ripple effects on our healthcare system and community wellbeing are becoming increasingly evident.

Beyond Simple Choices: The Complex Reality

Standing in my clinic, working with Australian families from all walks of life, I’ve come to understand that the disease-versus-lifestyle debate misses something crucial. Yes, obesity develops differently from infectious diseases—you can’t catch it from someone sitting next to you. But like many chronic conditions, it emerges from a web of interconnected factors that extend far beyond individual willpower.

Think of it like our native ecosystems. Just as the health of a forest depends not only on individual trees but on soil quality, rainfall patterns, native wildlife, and human intervention, obesity develops through the complex interaction between our genetic makeup and our environment. The WHO now acknowledges that “in most cases obesity is a multifactorial disease due to obesogenic environments, psycho-social factors and genetic variants.”

We now understand that epigenetics plays a crucial role in this process. Our genes don’t predetermine obesity, but they can be “switched on” by environmental factors, creating genuine challenges that make maintaining a healthy weight significantly harder for some people than others. It’s not about willpower—it’s about working with our individual biology in a food environment that has dramatically changed over the past few decades.

The Modern Food Landscape

Our current food environment has created what researchers call an “obesogenic landscape.” Ultra-processed foods are often cheaper and more accessible than whole foods, marketing targets our deepest psychological triggers, and our natural hunger and fullness signals are overwhelmed by engineered flavors designed to encourage overconsumption.

When I work with families, I often use the analogy of swimming upstream. Some people are naturally strong swimmers, while others face stronger currents due to their genetic makeup, stress levels, medication needs, or economic circumstances. Both groups can learn to swim effectively, but one will need more support and different strategies.

What This Means for Our Children

What concerns me most is how this affects our young ones. When children come to my clinic carrying both the physical and emotional weight of adult food decisions and environments, it becomes clear that framing obesity purely as a “lifestyle choice” doesn’t capture the full picture.

These children haven’t chosen their family’s food environment, economic circumstances, or genetic predispositions. They’re navigating a world where energy-dense, nutrient-poor foods are heavily marketed to them, where screen time often replaces active play, and where adult stress and busyness can impact family meal patterns.

The new clinical approach offers hope because it focuses on health outcomes rather than just weight. This means we can work with families to improve energy levels, reduce inflammation, stabilize mood, and enhance overall wellbeing—victories that may not always show up on the scales but represent genuine improvements in quality of life.

A More Compassionate Framework

The disease classification matters because it shapes how we approach treatment and, perhaps more importantly, how we speak with families about their experiences. When we frame obesity purely as a lifestyle issue, we often inadvertently add shame to an already challenging situation. In my experience, shame rarely motivates positive, sustainable change.

However, recognizing obesity as a disease doesn’t remove personal agency or diminish the importance of healthy choices. Instead, it acknowledges that some people face greater challenges in making and maintaining those choices, and they deserve medical support and community resources rather than judgment.

Practical Steps That Make a Difference

In my practice, I’ve found that the most effective approach combines medical understanding with practical, sustainable lifestyle changes. This holistic approach includes:

Supporting the whole family system: Since children learn eating patterns from their environment, involving the entire family in creating healthier food relationships is essential. Small changes that the whole family can embrace are more sustainable than dramatic restrictions placed on one person.

Focusing on blood sugar stability: Regular, balanced meals with adequate protein and healthy fats help prevent the blood sugar swings that can trigger cravings and emotional eating. This isn’t about perfection—it’s about creating more stable energy throughout the day.

Nurturing gut health: The connection between our microbiome and weight regulation is becoming clearer. Including fermented foods like kefir or sauerkraut, and fiber-rich vegetables helps support the beneficial bacteria that play a role in metabolism and satiety signals.

Managing stress and sleep: Both chronic stress and poor sleep disrupt the hormones that regulate hunger and fullness, making weight management exponentially more difficult. Simple practices like gentle evening routines or brief morning mindfulness can make a meaningful difference.

Finding joyful movement: Physical activities that bring pleasure rather than punishment help create sustainable habits. This might be dancing, gardening, walking with friends, or playing with children—whatever brings someone alive in their body.

I also work with specific nutrients that support healthy metabolism. Magnesium helps with stress management and blood sugar regulation, B vitamins support energy production, and adaptogenic herbs like Withania can help the body cope with the chronic stress that often underlies weight struggles.

Looking Forward with Hope and Realism

The development of new treatments like GLP-1 receptor agonists has been described as “an inflection point for the obesity market, because for the first time pharmacological interventions delivered meaningful weight loss of 10-15%.” While medications aren’t the complete answer, they represent genuine hope for individuals who have struggled despite their best efforts with lifestyle changes alone.

The evolution toward “clinical obesity” as a diagnostic framework represents progress in our understanding of this complex condition. It moves us away from a one-size-fits-all approach based solely on BMI toward individualized care that considers the full picture of someone’s health and circumstances.

As we move forward in 2025, the most healing approach honors both the biological reality of obesity as a complex medical condition and the empowering truth that our daily choices matter. We can hold space for the complexity of this condition while supporting individuals and families in creating the healthiest, most vibrant lives possible within their unique circumstances.

The goal isn’t perfection or conforming to external standards—it’s progress toward health, vitality, and the kind of self-compassion that makes sustainable change possible. When we approach weight and health challenges with both scientific understanding and genuine empathy, we create the conditions where true healing can begin.

This isn’t about quick fixes or dramatic transformations. It’s about sustainable changes that honor both our biology and our humanity, creating space for families to thrive regardless of where they’re starting from.

If you or your family are navigating weight-related health concerns, please know that support is available.  I work with families to address these challenges using a holistic, compassionate approach that honors both the medical complexity and the human side of health. You can reach out to me at karenmcelroy.com.au/contact to discuss how we might work together.