What Are Health Behaviors and What Influences Them?

Health behaviors are the actions people take that affect their physical and mental well-being, from eating patterns and exercise habits to smoking, alcohol use, sleep routines, and whether they follow medical advice. What influences these behaviors is not a single force but a layered mix of psychology, biology, social environment, economics, and policy. Research consistently shows that these behaviors tend to cluster together and become harder to change with age, meaning that a person who smokes is also more likely to eat poorly and be physically inactive.

What Counts as a Health Behavior

The term covers a broad range of actions, and researchers generally split them into health-promoting behaviors (regular physical activity, eating fruits and vegetables, getting preventive screenings, wearing a seatbelt) and health-risk behaviors (tobacco use, excessive drinking, unprotected sex, sedentary living). These are not always binary choices. Most people fall somewhere on a spectrum for each behavior, and the same person can be diligent about exercise while neglecting sleep or dental care.

One important finding is that health behaviors rarely exist in isolation. People tend to carry clusters of risk behaviors or clusters of protective ones. A large review of the evidence found that risk behaviors are prevalent, increase with age, and co-occur as bundles rather than randomly distributing across a population.¹ This clustering matters practically because interventions targeting just one behavior in someone carrying several may produce disappointing results if the underlying drivers of the whole cluster go unaddressed.

The Psychology Behind Health Decisions

Several well-tested psychological frameworks explain why people adopt or avoid certain health behaviors. They overlap in places but emphasize different levers.

The Health Belief Model, one of the oldest and most widely applied, says people are more likely to act when they believe they are personally vulnerable to a health threat, that the threat is serious, that taking action has clear benefits, and that the barriers to action are manageable. Self-efficacy, or the confidence that you can actually pull off the behavior, ties the whole thing together. Research on this model has found that exposure to health messages leads to behavior change most effectively when perceived barriers and threat are addressed and self-efficacy moderates the process.² A study applying this model to college students’ weight management found that perceived threat, perceived benefits, and self-efficacy in both exercise and dieting all independently predicted whether students intended to manage their weight.³

The Theory of Planned Behavior takes a different angle, focusing on three predictors of intention: your personal attitude toward the behavior, what you think important people around you expect (the social norm), and how much control you believe you have over it. Intentions to perform behaviors can be predicted with high accuracy from these three factors, and intentions together with perceived control account for considerable variance in actual behavior.⁴ Interestingly, the relationship between these predictors is not always straightforward. When people feel they have high control over a behavior, their personal attitude becomes more important and social pressure matters less. When control feels low, social norms gain influence.⁵ This helps explain why peer influence seems to dominate some behaviors (like teenage drinking, where individual control feels limited) while personal values dominate others (like choosing to recycle).

Social Cognitive Theory, developed by Albert Bandura, emphasizes that people learn health behaviors not only through their own experience but by watching others. A scoping review of studies applying this theory in primary care found that self-efficacy was the most consistently used and effective construct, followed by observational learning through role models.⁶ In patients with type 2 diabetes, self-regulation and self-efficacy were the strongest predictors of physical activity behavior, while social support and self-regulation best predicted dietary behavior.⁷ The practical takeaway from all three models is that self-efficacy shows up as a common thread. People who believe they can change are more likely to try, and more likely to succeed.

Social Networks Spread Behaviors Like Contagion

Your friends, family, and broader social network shape your health behaviors in ways that go well beyond peer pressure. A landmark study tracking over 12,000 people across 32 years found that a person’s chance of becoming obese increased by about 57% if a friend became obese in a given time period. Among siblings, the increase was about 40%, and among spouses, roughly 37%. Strikingly, geographic neighbors who were not part of the social network showed no such effect, suggesting the mechanism is social rather than environmental.⁸ The effect extended up to three degrees of separation, meaning your friend’s friend’s friend could influence your weight.

Experimental work has confirmed that this is not just correlation. In an online social network experiment, individual adoption of a new health behavior was much more likely when participants received reinforcement from multiple people in their network, and the behavior spread farther and faster through tightly clustered social networks than through loosely connected ones.⁹ This has real implications for health promotion: programs that recruit groups of friends or coworkers rather than isolated individuals may produce stronger and more durable effects.

Socioeconomic Status and the Built Environment

Money, education, and neighborhood design are among the most powerful predictors of health behavior, and their effects start early. The inverse relationship between socioeconomic status and unhealthy behaviors like tobacco use, physical inactivity, and poor nutrition has been demonstrated across many studies, though the underlying reasons vary.¹⁰ It is not simply that poorer people “choose” worse behaviors. They often face restricted access to fresh food, safe places to exercise, quality healthcare, and reliable information. Stress from financial insecurity adds another layer.

These patterns are visible in children and adolescents as well. A systematic review found that young people from lower socioeconomic backgrounds face elevated risk of early smoking initiation, consumption of energy-dense foods, low physical activity, and involvement in drug use, compared to peers in higher socioeconomic groups.¹¹ The built environment, meaning the physical design of communities including neighborhood walkability, access to parks, availability of grocery stores versus fast-food outlets, and the presence of recreational facilities, further shapes these patterns at a population level.¹²

Culture, Language, and Health Literacy

A person’s cultural background shapes what they consider “healthy,” how they interpret symptoms, and whether they trust medical providers. Cultural beliefs around illness and wellness can conflict with a provider’s instructions in ways that both sides may not even recognize. Cultural and language differences interact with socioeconomic status to contribute to low health literacy, which in turn makes it harder for people to understand or act on medical guidance.¹³ Limited health literacy is recognized as contributing to health disparities through poor understanding, weak adherence to treatments, and limited access to care. When cultural differences between patient and provider go unaddressed, they can produce poor health outcomes through misunderstanding and value conflicts.¹⁴

Trust in a physician is part of this equation. Research has shown that communication quality and general satisfaction with a physician positively affect patient trust, while communication barriers reduce it. When patients trust their physician, they are more likely to follow treatment recommendations.¹⁵ The growing presence of health misinformation on social media adds a complicating layer. While the direct behavioral impact of misinformation exposure is still poorly quantified, researchers note it can create the impression that no expert consensus exists, generate mistrust in official sources, and lead people to disengage from health information seeking or avoid care altogether.¹⁶

The Brain’s Role in Health Behavior

Beneath the psychological models and social influences lie neurological processes that can make health behaviors surprisingly resistant to conscious intentions. Habits form through repeated behavior in consistent contexts, and once established, they run on autopilot. A systematic review and meta-analysis of habit formation found that factors like frequency of repetition, timing, individual choice over the behavior, and emotional associations all influence how strong a habit becomes. Morning practices and self-selected habits tend to develop greater strength than those imposed externally or performed at inconsistent times.¹⁷

Stress works against healthy habits by degrading the brain’s executive functions, the mental processes that handle planning, impulse control, and decision-making. Both animal and human research indicates that chronic stress negatively affects these executive processes, leading to maladaptive behavior.¹⁸ This was demonstrated clearly during the COVID-19 pandemic: people who already had weaker executive function before the pandemic experienced greater negative changes in physical activity, eating habits, and in some groups, alcohol or substance use.¹⁹

Genetics add yet another dimension. Variations in dopamine-related genes are thought to influence how people process rewards, which in turn affects susceptibility to addictive behaviors and social cognition.²⁰ Research on what has been called “reward deficiency syndrome” has found that certain variants of the dopamine D2 receptor gene are associated with higher rates of alcoholism, drug abuse, smoking, obesity, and compulsive gambling. These are polygenically inherited, meaning each gene accounts for only a small portion of the total risk, but the cumulative effect can be meaningful.²¹ None of this means health behavior is “hardwired.” It means some people start with a steeper hill to climb when trying to change specific habits.

Childhood Experiences Leave Lasting Marks

What happens in early life can set the trajectory for health behaviors decades later. Adverse childhood experiences such as abuse, neglect, household dysfunction, and exposure to violence are reliably linked to greater engagement in health-risk behaviors. A study of over 500 children placed in foster care found that higher scores on a measure of adverse childhood experiences predicted greater involvement in violence, substance use, and delinquency even among 9-to-11-year-olds, regardless of sex or minority status.²²

The effects persist into adulthood. A large study found that each additional adverse childhood experience was associated with a 4 to 34% increase in the odds of unhealthy behaviors or adverse health outcomes later in life. People reporting four or more such experiences showed elevated rates of drinking, smoking, and high-risk HIV behavior, alongside chronic conditions like cardiovascular disease and depression.²³ Socioeconomic inequality mediated some of these relationships, meaning that childhood adversity partly affects adult behavior by limiting economic opportunity. This finding underscores that health behaviors are not purely a matter of personal discipline. The deck can be stacked long before a person is old enough to make choices for themselves.

Why Behavior Change Is Rarely a Straight Line

People trying to improve their health behaviors should expect setbacks. The Transtheoretical Model, one of the most widely used frameworks in clinical behavior change, describes progress through stages: from not even thinking about change, to considering it, preparing for it, taking action, and eventually maintaining the new behavior over time.²⁴ Crucially, relapse is treated not as failure but as a normal part of the cycle. People frequently recycle through earlier stages before achieving lasting change, and researchers have emphasized that debriefing setbacks and learning from them is essential to eventual success.²⁵

A related distinction comes from the Health Action Process Approach, which separates the motivational phase (forming an intention to change) from the volitional phase (actually carrying it out). Many people get stuck in the gap between intending to change and doing so.²⁶ A systematic review of predictors of lapse and relapse found that self-efficacy was the only consistent predictor across different outcomes, predicting both lapse and relapse in physical activity and relapse in dietary behavior. For most other variables, the evidence was too thin to draw firm conclusions.²⁷ Removing barriers, creating supportive environments, and developing self-efficacy are all important to maintaining new behaviors, and goal setting and self-regulation techniques can help build competence over time.²⁸

Policy Levers That Actually Shift Population Behavior

Individual psychology matters, but population-level health behaviors respond powerfully to policy. Two broad categories of policy intervention have strong evidence behind them: taxes and nudges.

Health taxes work by raising the price of harmful products. A systematic review of empirical studies concluded that taxes increasing the price of unhealthy products by 20% or more are effective at reducing consumption.²⁹ Taxes on tobacco and alcohol have generated substantial health gains, while taxes on food and non-alcoholic beverages tend to show effects that build over time and are strongest among people with lower incomes.³⁰ Modeling research has estimated that sugar taxes and salt taxes produce the largest per-capita health gains, while subsidies on fruits and vegetables also yield meaningful improvement.³¹

Nudges take a different approach. Instead of changing prices or restricting options, they redesign the choice environment to make healthier options easier or more visible. A comprehensive meta-analysis of over 200 studies found that these “choice architecture” interventions produce a small to medium effect on behavior change overall.³² In food purchasing specifically, priming nudges (manipulating physical or sensory cues), salience nudges (drawing attention to healthy options), and default nudges (making healthy options the preset choice) have all shown promise.³³ These modifications tend to be low-cost and feasible even in settings serving low-income populations, such as food pantries and stores accepting government nutrition benefits.³⁴

Wearables and Digital Health Tools

Technology is increasingly part of the behavior-change equation. Fitness trackers, smartwatches, and smartphone apps use techniques like goal setting, feedback loops, and social comparison to encourage healthier habits. A comprehensive review of behavior change techniques embedded in wearables and connected devices highlighted their promising role in promoting positive behavior modifications and improving well-being.³⁵

Some newer platforms go beyond step counts. A digital health application that integrated food logging, physical activity tracking, continuous glucose monitoring, and heart rate data to deliver personalized lifestyle recommendations was shown to enhance healthy lifestyle practices and improve metabolic health in people both with and without type 2 diabetes.³⁶ The appeal of these tools is that they can make the feedback loop between action and outcome almost immediate: you eat something, your glucose data shifts, and the app tells you about it within hours. That rapid feedback loop taps directly into the self-regulation and self-efficacy processes that the psychological models consistently identify as critical.

The Evolutionary Mismatch Angle

One framework that has gained traction in lifestyle medicine reframes unhealthy behaviors not as moral failures but as evolutionary mismatches. Our ancestors’ bodies evolved in environments where calorie-dense food was scarce, physical activity was unavoidable, and chronic psychological stress was rare. Modern environments have flipped all of these conditions: high-calorie food is everywhere, physical activity requires deliberate effort, and chronic stress is common. Researchers have proposed that educating patients about this evolutionary mismatch could augment behavior-change efforts by reducing self-blame and reframing the challenge as one of navigating a mismatched environment rather than simply lacking willpower.³⁷ Whether this narrative actually improves outcomes is still being tested, but the underlying logic aligns with the broader evidence: health behavior is shaped far more by the environment around us than by sheer individual resolve.