Dr Alwin Tan, MBBS, FRACS, EMBA (Melbourne Business School)

Senior Surgeon | Governance Leader | HealthTech Co-founder
Harvard Medical School — AI in Healthcare
Australian Institute of Company Directors — GAICD candidate
University of Oxford — Sustainable Enterprise

Institute for Systems Integrity

Obesity is often framed as a problem of personal responsibility.

Eat less.
Move more.
Exercise discipline.

This framing appears intuitive. Yet it struggles to explain a central fact of the modern obesity epidemic.

Obesity rates have increased across nearly every region of the world over the past four decades. According to the World Health Organization, global obesity has more than doubled since 1990 and now affects over one billion people worldwide (WHO, 2025).

When a health outcome appears across populations, countries and cultures at that scale, the explanation is unlikely to lie solely in individual behaviour.

The more plausible explanation is that the systems surrounding those behaviours have changed.

From a systems perspective, obesity can be understood as an emergent outcome of modern food environments, economic incentives, urban design and healthcare structures interacting together.

The shift from individual behaviour to system design

Public health research increasingly recognises that health outcomes are shaped by environments as much as by individual choices.

Food availability, pricing structures, marketing exposure, transport infrastructure, working patterns and healthcare access all influence how people eat and move in daily life.

These environmental influences are often referred to as the commercial and structural determinants of health.

In the context of obesity, several structural features have become particularly influential.

Ultra-processed foods have become widely available and inexpensive.
Food marketing exposure has increased dramatically, particularly for children.
Urban environments in many regions prioritise cars rather than active mobility.
Long working hours and economic pressures shape eating patterns and physical activity.

None of these forces operate at the level of individual willpower.

They operate at the level of system design.

The commercial drivers of food consumption

One of the most powerful structural drivers of modern diets is the economic design of the global food system.

Many highly profitable food products are engineered to maximise consumption.

These products typically combine high levels of sugar, fat and salt in ways that stimulate reward pathways in the brain and encourage repeat consumption. Research has described these formulations as hyper-palatable foods (Gearhardt et al., 2011).

Ultra-processed foods also possess several commercial advantages:

• long shelf life
• low production costs
• strong branding potential
• global scalability

These characteristics make them economically attractive for manufacturers and retailers.

From a commercial standpoint, increasing consumption is the logical goal.

From a public health perspective, this dynamic creates an environment where overconsumption becomes structurally encouraged.

Monteiro et al. (2019) demonstrated that ultra-processed foods now contribute a large proportion of total caloric intake in many high-income countries and are strongly associated with obesity and metabolic disease.

This illustrates an important systems principle.

When incentives within a system favour a particular outcome, that outcome becomes more common.

Policy interventions that reshape environments

Because obesity is influenced by environmental conditions, several policy interventions focus on reshaping those environments rather than targeting individual behaviour alone.

Evidence is strongest in several areas.

Food marketing restrictions

Children are particularly vulnerable to food advertising.

Systematic reviews show that exposure to unhealthy food marketing significantly influences children’s food preferences and consumption patterns (Boyland et al., 2025).

Restrictions on marketing to children therefore represent an upstream intervention that alters the informational environment.

Sugar-sweetened beverage taxes

Taxes on sugar-sweetened beverages are one of the most widely studied fiscal interventions in nutrition policy.

A systematic review and meta-analysis found that such taxes consistently reduce purchases and consumption of sugary drinks (Teng et al., 2019).

By altering price signals, governments can influence purchasing behaviour at the population level.

Urban design and active mobility

Urban environments also shape physical activity patterns.

Neighbourhoods designed to support walking, cycling and public transport encourage greater physical activity and are associated with lower obesity risk (Sallis et al., 2020).

Conversely, environments designed primarily for car travel reduce opportunities for routine movement.

Healthcare access and obesity treatment

While prevention is essential, millions of people already live with obesity and require access to effective care.

The WHO health service delivery framework for obesity emphasises integrating prevention and treatment within health systems across the life course (WHO, 2023).

This includes behavioural support, pharmacotherapy and metabolic surgery when appropriate.

Prevention and treatment should therefore be viewed as complementary rather than competing strategies.

The role of stigma in health systems

Another systemic factor that affects obesity outcomes is stigma within healthcare.

Research shows that weight stigma can reduce patient trust, discourage individuals from seeking care and worsen health outcomes (Phelan et al., 2015).

When patients anticipate judgement within healthcare environments, they may delay treatment or disengage from care altogether.

This illustrates a broader systems insight.

Healthcare systems do not simply treat health conditions. They also shape patient behaviour through the way care is delivered.

Governance and policy fragmentation

One of the major challenges in addressing obesity is that the drivers of the problem lie across multiple policy domains.

Food regulation
Agricultural policy
Urban planning
Education systems
Transport infrastructure
Healthcare systems
Advertising regulation

These sectors often operate independently, with separate institutions, incentives and policy frameworks.

The result is fragmented governance.

Policies that influence population health may therefore evolve without coordination.

From a systems perspective, obesity can be understood as the aggregate outcome of these fragmented decisions.

A systems integrity perspective

The Institute for Systems Integrity examines how outcomes emerge from the interaction of structures, incentives and decision systems.

From this perspective, persistent large-scale health outcomes rarely arise solely from individual choices.

They arise when system design consistently nudges behaviour in particular directions.

Obesity illustrates this dynamic clearly.

Food environments encourage consumption.
Urban environments may discourage movement.
Economic pressures shape daily routines.
Healthcare systems sometimes struggle to provide coordinated prevention and treatment.

When these influences align in the same direction, population-level outcomes follow.

Conclusion

The modern obesity epidemic cannot be understood purely as a matter of personal responsibility.

It reflects the interaction of economic incentives, commercial practices, built environments and healthcare systems.

Addressing obesity therefore requires more than education or awareness campaigns.

It requires system-level alignment across policy domains.

Environments must support healthier choices.
Commercial incentives must align with health goals.
Healthcare systems must provide respectful and effective care.

When systems change, behaviour changes with them.

Understanding obesity through a systems lens is therefore not an attempt to remove individual responsibility.

It is an attempt to diagnose the problem accurately.

Because effective solutions begin with correct diagnosis.

References

Boyland, E. et al. (2025) Impact of food and beverage marketing on diet-related outcomes.

Gearhardt, A.N., Corbin, W.R. and Brownell, K.D. (2011) ‘Food addiction: An examination of the diagnostic criteria for dependence’, Journal of Addiction Medicine.

Monteiro, C.A. et al. (2019) ‘Ultra-processed foods: what they are and how to identify them’, Public Health Nutrition.

Phelan, S.M. et al. (2015) ‘Impact of weight bias and stigma on quality of care and outcomes’, Obesity Reviews.

Sallis, J.F. et al. (2020) ‘Built environment, physical activity and obesity’, Annual Review of Public Health.

Teng, A. et al. (2019) ‘Impact of sugar-sweetened beverage taxes on purchases and dietary intake’, Obesity Reviews.

World Health Organization (2023) Health service delivery framework for prevention and management of obesity.

World Health Organization (2025) Obesity and overweight fact sheet.