Overweight

Overweight affects billions of people worldwide, and understanding this condition is the first step toward making positive changes for your health and well-being.

What is overweight
How common is overweight
Measuring overweight
What causes overweight
Health risks of overweight
Who is most affected
Treatment and management

What is overweight

Overweight is a condition where a person has more body fat than is considered healthy for their height. According to the World Health Organization, overweight is defined as having a body mass index (BMI) greater than or equal to 25^[1]. It is different from obesity, which is a more severe form defined by a BMI of 30 or higher^[1].

A healthy body needs some fat to function properly. Fat helps with hormone production, keeping you warm, protecting sensitive areas, and storing energy for later use^[8]. However, when too much fat builds up in the body, it can make movement difficult and increase the risk of developing serious health problems^[2].

While overweight is commonly defined by BMI, this measurement doesn’t tell the complete story. Some people, such as athletes with a lot of muscle, may have a BMI in the overweight range even though they don’t have too much body fat^[5]. Your doctor may also measure your waist size to better understand your health risks^[2].

How common is overweight

Overweight is a widespread condition affecting people around the world. In 2022, about 2.5 billion adults aged 18 years and older were overweight globally. This means that 43% of all adults were overweight^[1].

The number of people affected by overweight has grown dramatically over recent decades. Worldwide adult obesity has more than doubled since 1990, and among young people aged 5 to 19 years, obesity has quadrupled during the same period^[1].

In the United States, more than 2 in 5 adults have obesity, making it a very common condition^[2]. Overweight is especially common in places where food supplies are plentiful and people tend to sit for long periods during the day^[8].

The condition also affects children. In 2024, 35 million children under the age of 5 were overweight. Among children and adolescents aged 5 to 19 years, over 390 million were overweight in 2022^[1].

Measuring overweight

Doctors diagnose overweight by measuring a person’s weight and height and calculating the body mass index (BMI). BMI is calculated by dividing weight in kilograms by height in meters squared. It gives a general estimate of body fat based on these measurements^[1].

For adults, the BMI categories are straightforward. A BMI between 18.5 and 24.9 is considered a healthy weight range. Overweight is defined as a BMI from 25 to 29.9. When BMI reaches 30 or higher, this is classified as obesity^[6].

For children and adolescents, age must be taken into account when defining overweight. In children under 5 years of age, overweight is defined as weight-for-height greater than 2 standard deviations above WHO Child Growth Standards median^[1]. For children aged between 5 and 19 years, overweight is defined as BMI-for-age greater than 1 standard deviation above the WHO Growth Reference median^[1].

In addition to BMI, doctors may also measure waist size, as this can help identify additional health risks. In the United States, a waist measurement of more than 35 inches in women or 40 inches in men can be a risk factor for cardiovascular disease or type 2 diabetes^[2]. Where you carry extra weight may indicate whether you have a higher risk of health problems^[2].

What causes overweight

At the most basic level, overweight develops when you consume more calories than your body uses over time. This is called an energy imbalance. When the energy you take in from food and drinks does not equal the energy your body uses for breathing, digesting food, and being physically active, the extra energy is stored as fat^[4].

However, becoming overweight is much more complex than simply eating too much. Many factors can contribute to weight gain, and they often work together to make it difficult to maintain a healthy weight.

Your eating habits play an important role. Consuming more calories than your body needs, eating highly processed foods, foods high in sugar, and foods with large amounts of saturated fat can all contribute to overweight^[2].

Physical activity levels matter as well. Spending a lot of time watching TV, playing video games, or using phones and computers reduces the time available for physical activity^[2].

Other important factors include lack of sleep. Missing out on at least seven hours of sleep can affect the hormones that control hunger^[2]. Stress can also lead to weight gain. When you’re stressed, your body produces more hormones like cortisol that affect hunger, and you may be more likely to eat high-fat, high-sugar comfort foods^[2].

Genetics can influence weight as well. Research shows that some people carry specific genes that affect appetite^[2]. Family habits, culture, and where you live and work can also play a role^[4].

Certain medications, such as antidepressants, steroids, anti-seizure medications, and diabetes medications, may contribute to weight gain^[2]. Underlying health conditions like metabolic syndrome and polycystic ovary syndrome can also cause weight gain as a side effect^[2].

As people age, their body composition gradually changes. The proportion of muscle decreases and the proportion of fat increases. This shift slows down metabolism, making it easier to gain weight^[16].

Health risks of overweight

Overweight can increase the risk of developing many serious health problems. Understanding these risks is important because even modest weight loss can help prevent or improve many of these conditions^[5].

One of the main concerns is that overweight can lead to an increased risk of type 2 diabetes and heart disease. It can also affect bone health and reproduction, and increases the risk of certain cancers^[1].

People with overweight may also develop high blood pressure, high cholesterol, stroke, gallbladder disease, and osteoarthritis. Sleep apnea, a condition where breathing repeatedly stops and starts during sleep, is also more common in people with overweight^[2].

The condition can affect quality of life in many ways, including problems with sleeping or moving comfortably^[1]. It can also affect self-esteem and mental health^[2].

Many adults with overweight have other serious chronic diseases. For example, 58% of U.S. adults with obesity have high blood pressure, which is a risk factor for heart disease. About 23% of U.S. adults with obesity have diabetes^[3].

The good news is that even a small amount of weight loss can make a big difference. Losing 5% to 10% of body weight can significantly improve health and quality of life^[11].

Who is most affected

Overweight does not affect all groups of people equally. Some populations face higher risks due to various social, economic, and environmental factors.

In the United States, some racial and ethnic groups have higher rates of obesity. During 2017 to March 2020, non-Hispanic Black adults had the highest obesity rate at 49.9%, followed by Hispanic adults at 45.6%, non-Hispanic White adults at 41.4%, and non-Hispanic Asian adults at 16.1%^[3].

Education level also plays a role. People with a high school diploma or some college education had the highest obesity rates at 46.4%, followed by those with less than a high school diploma at 40.1%, and those with a college degree or above at 34.2%^[3].

The greatest number of people living with overweight are in low- to middle-income countries. Poverty and food insecurity are important drivers of overweight, as people may lack access to healthy and affordable food and quality healthcare. They may also have fewer opportunities for physical activity^[19].

People in lower-income households may experience cycles of not having enough food followed by overeating, as well as higher levels of stress and anxiety, which can promote weight gain^[19].

Treatment and management

Treatment for overweight focuses on helping people make lasting lifestyle changes to lose weight safely and keep it off over the long term. The goal is not just to lose weight, but to reduce the risk of health problems and improve quality of life^[10].

Most treatment plans include changes in three main areas: eating habits, physical activity, and behavior^[13]. Working with a healthcare professional is important to develop a plan that works for your specific situation.

Healthy eating is a key part of weight management. Your doctor or dietitian can help you figure out how many calories you need each day and teach you about shopping for healthy foods, reading nutrition labels, choosing healthy snacks, understanding portion sizes, and avoiding sweetened drinks^[14]. It’s important to eat a variety of healthy foods rather than cutting out entire food groups^[15].

A healthy diet should include plenty of fruits and vegetables, meals based on starchy foods like potatoes, bread, rice, and pasta (choosing high fiber and wholegrain varieties when possible), some milk and dairy products, some meat, fish, eggs, beans and other protein sources, and only small amounts of foods and drinks that are high in fat and sugar^[14].

Physical activity is another important part of treatment. Many health benefits come from being physically active and getting the recommended amount of activity each week. Physical activity helps you burn energy and maintain weight loss over time^[11]. Adults need at least 150 minutes of moderate-intensity physical activity each week, which can be broken down into 30 minutes a day, 5 days a week. This could include activities like brisk walking^[16].

Behavioral changes are essential for long-term success. This includes keeping track of what you eat and how much you exercise, setting realistic goals, managing stress without turning to food, getting enough sleep, and finding support from family and friends^[13].

Your doctor may recommend working with a weight management program. These programs typically include 14 or more counseling sessions over 6 months, an eating plan based on your body’s needs, regular physical activity, daily tracking of food and activity, and regular feedback and support from specialists^[10].

In some cases, your doctor may recommend weight-loss medicines along with lifestyle changes. These medications can help when diet and exercise alone are not enough^[11].

For people with severe obesity, weight-loss surgery (also called bariatric surgery) may be an option. This is usually considered when other treatments have not worked and when obesity is causing serious health problems^[13].

Weight loss takes time and effort. Most experts recommend losing weight at a safe and sustainable rate of 0.5 to 1 kilogram per week^[14]. A weight loss of 5% of your body weight over 6 months may be a good initial goal^[10].

Support from family, friends, and caregivers can make a big difference. Having strong social support is a key factor in sticking to weight management habits long-term^[19]. Support groups, either in person or online, can also provide encouragement, tips, and motivation^[17].