Causes of Obesity in Men and Women: 10 Major Risk Factors You Should Know
Obesity has become one of the major public-health challenges affecting both men and women around the world.
It is much more complicated than simply eating too much.
The World Health Organization describes obesity as a chronic, relapsing disease arising from complex interactions involving genetics, neurobiology, eating behaviours, access to healthy food, environmental influences and other factors.
In 2022, according to WHO, about one in eight people worldwide was living with obesity, while 2.5 billion adults were overweight, including approximately 890 million adults living with obesity.
Understanding why people gain excessive weight is therefore important not only for appearance but also for long-term health.
What Is Obesity?
For adults, body mass index, or BMI, is commonly used as a screening measurement calculated from a person’s weight relative to height.
WHO defines adult overweight as a BMI of 25 or higher and obesity as a BMI of 30 or higher.
BMI has limitations and does not provide a complete assessment of an individual’s health or body composition. Waist circumference and other clinical measurements can therefore provide additional information.
1. Regular Consumption of High-Calorie Foods
Diet can play a significant role in weight gain.
Frequently consuming energy-dense foods, particularly foods high in added sugars and unhealthy fats, can make it easier to consume more energy than the body uses.
Sugary drinks can be particularly easy to consume in large quantities because they add calories without necessarily creating the same feeling of fullness as some solid foods.
Over time, persistent excess energy intake can contribute to fat accumulation.
2. Physical Inactivity and Sedentary Living
Modern lifestyles have dramatically reduced the amount of movement required in everyday life.
Many adults spend hours sitting at desks, driving, watching television or using phones and computers.
When physical activity declines while energy intake remains high, weight gain becomes more likely.
Regular physical activity also provides benefits extending well beyond weight management, including cardiovascular and metabolic health.
3. Genetics and Family History
Some people are genetically more susceptible to obesity than others.
Genes can influence appetite, metabolism, fat distribution and how the body responds to food and physical activity.
Having a family history of obesity does not mean someone will inevitably develop obesity, because behaviour and environment also matter. However, genetic susceptibility can make weight management more difficult for some individuals.
4. Hormonal and Medical Factors
Certain medical conditions can contribute to weight gain or make weight management more challenging.
Hormonal and metabolic factors may influence appetite, energy expenditure and fat storage.
For women, life stages such as pregnancy and menopause can also affect body composition and weight.
Anyone experiencing rapid, unexplained or persistent weight gain should consider medical assessment rather than assuming diet is necessarily the only cause.
5. Certain Medications
Some medicines can contribute to weight gain in certain people.
Depending on the individual and medication, this can occur through changes in appetite, metabolism, fluid retention or activity levels.
People concerned that medication is affecting their weight should not stop prescribed treatment without medical advice. A doctor or pharmacist can assess whether an alternative treatment or weight-management strategy is appropriate.
6. Poor or Insufficient Sleep
Sleep and body weight are closely connected.
Inadequate sleep can influence hormones and behaviours associated with appetite and food choices. Tiredness may also reduce motivation for physical activity.
People who regularly sleep too little may therefore find maintaining a healthy weight more difficult.
Good sleep should be considered part of overall health rather than a luxury.
7. Stress and Emotional Eating
Long-term stress can influence eating behaviour.
Some people respond to emotional pressure, anxiety or exhaustion by eating more frequently or choosing highly palatable, calorie-dense foods.
This can gradually contribute to weight gain, particularly when combined with limited physical activity and poor sleep.
Addressing stress, therefore, may be an important component of sustainable weight management for some people.
8. Alcohol and High-Calorie Drinks
Calories are not consumed through food alone.
Alcoholic drinks, sweetened beverages, energy drinks and some highly sweetened coffee beverages can contribute substantial calories to a person’s daily intake.
Regular consumption can make maintaining energy balance more difficult.
Replacing sugary drinks with water or unsweetened alternatives can be a useful step for many people.
9. Age and Changes in Lifestyle
People’s bodies and lifestyles change as they grow older.
Physical activity may decline, muscle mass can change and daily energy requirements may decrease.
Continuing the same eating patterns while becoming substantially less active can gradually lead to weight gain.
Age itself does not make obesity inevitable, but maintaining muscle strength, physical activity and appropriate nutrition becomes increasingly important.
10. Environment and Modern Lifestyle
Obesity cannot be understood solely as an issue of individual willpower.
Where people live, work and shop can strongly influence their choices.
Healthy food may be expensive or difficult to obtain, while highly processed foods can be cheap and widely available. Long working hours, limited recreational spaces, dependence on cars and unsafe neighbourhoods can also reduce opportunities for physical activity.
These environmental factors help explain why obesity has increased across many countries.
Does Obesity Affect Men and Women Differently?
Both men and women can develop obesity, but biological and hormonal differences can influence where body fat accumulates.
Men commonly accumulate more abdominal or visceral fat, while premenopausal women often store proportionally more fat around the hips and thighs. Patterns can change with age and hormonal changes.
Excess abdominal fat is particularly important because it is associated with metabolic and cardiovascular risk.
Individual risk, however, cannot be determined by sex or body shape alone.
Health Problems Associated With Obesity
Obesity is not merely a cosmetic concern.
Excess body fat is associated with increased risk of several serious conditions, including:
Type 2 diabetes
High blood pressure
Heart disease
Stroke
Certain cancers
Osteoarthritis and other musculoskeletal problems
Sleep-related breathing problems
Other metabolic disorders
WHO estimates that higher-than-optimal BMI contributed to approximately 3.7 million deaths from noncommunicable diseases in 2021.
How Can People Reduce Their Risk?
There is no single weight-management strategy that works for everyone.
For many people, sustainable improvements begin with healthier food choices, appropriate portion sizes, increased physical activity, sufficient sleep and reducing consumption of sugary drinks and highly energy-dense foods.
WHO recommends that adults undertake at least 150 minutes of moderate physical activity each week as part of a healthy lifestyle.
People already living with obesity may benefit from professional support. Depending on the person’s health, this could include nutritional counselling, behavioural interventions, medical treatment or other evidence-based obesity care.
The Bottom Line
Obesity in men and women has multiple causes.
Food intake and physical inactivity are important, but genetics, biology, environment, medications, sleep, stress, socioeconomic circumstances and medical conditions can also contribute.
The most effective approach is therefore not to stigmatise people because of their weight but to identify the factors contributing to weight gain and address them appropriately.
Maintaining a healthier weight can reduce the risk of diabetes, cardiovascular disease and several other chronic illnesses.
Anyone experiencing significant or unexplained weight gain, or struggling to manage obesity despite lifestyle changes, should speak with a qualified healthcare professional for an individual assessment.
Medical Disclaimer: This feature is for general educational purposes and should not replace professional medical diagnosis, treatment or personalised nutritional advice.
