Overweight is a condition where a person carries more body fat than is considered healthy for their height. It affects billions of people worldwide and can increase the risk of serious health problems, but with the right support and lifestyle changes, people can work toward a healthier weight and improved quality of life.
Understanding Overweight and How Common It Is
When we talk about being overweight, we’re describing a situation where someone has more body fat than what’s typically healthy for their body. This isn’t just about appearance—it’s a medical concern that can affect how the body works and a person’s overall health. The term overweight specifically refers to having a body mass index (BMI)—a calculation using weight and height—between 25 and 29.9. When BMI reaches 30 or higher, it’s classified as obesity, which is considered a chronic disease involving excessive fat deposits that can impair health.[1]
The numbers are staggering when we look at how many people around the world are dealing with this condition. In 2022, roughly 2.5 billion adults aged 18 years and older were overweight globally. This means that 43% of all adults—nearly half—carried more weight than what’s considered healthy. Among these adults, 890 million were living with obesity. The situation has worsened dramatically over time: worldwide adult obesity has more than doubled since 1990, and adolescent obesity has quadrupled during the same period.[1]
The problem doesn’t spare children either. In 2024, 35 million children under the age of five were overweight. When looking at older children and teenagers aged 5 to 19 years, more than 390 million were overweight in 2022, and 160 million of them were living with obesity.[1] These figures tell us that overweight and obesity are not rare conditions affecting a few people—they’re common health challenges touching families in every corner of the world.
In the United States specifically, more than two in five adults have obesity, which translates to over 100 million adults. The numbers have climbed steadily: obesity prevalence increased from 30.5% in 1999-2000 to 41.9% in 2017 through March 2020. During that same time, severe obesity—defined as a BMI of 40 or higher—rose from 4.7% to 9.2%, affecting more than 22 million adults.[3]
Why Do People Become Overweight?
At its most basic level, becoming overweight happens when someone consumes more calories than their body uses over time. Think of it as an energy imbalance: the energy coming in through food and drinks doesn’t match the energy going out through daily activities, breathing, digesting food, and physical movement. When this imbalance continues, the body stores the extra energy as fat—primarily as triglycerides in fatty tissue.[4]
But understanding why someone is overweight isn’t as simple as saying they “eat too much.” Many complex factors work together to influence a person’s weight. Some people carry specific genes that affect their appetite and how their body handles food. Research shows that people with obesity often carry what scientists call obesity-susceptibility genes, though it’s not entirely clear how these genetic factors interact with everything else.[2]
The foods available in someone’s environment play a huge role. When people regularly consume more calories than they need—especially from ultra-processed foods, items high in sugar, and foods with large amounts of saturated fat—weight gain becomes more likely. The same happens when people drink beverages loaded with sugar, including alcohol.[2]
Physical limitations matter too. Adults and children with physical and learning disabilities face higher risks of becoming overweight. They may encounter barriers to physical activity, and there might not be adequate specialized education and resources available to help them maintain a healthy weight.[2]
Some medications that treat other health problems can contribute to weight gain as a side effect. These include certain antidepressants, steroids, medications for seizures, diabetes medications, and beta-blockers. If you’re taking any medication and notice weight changes, it’s important to discuss this with your healthcare provider rather than stopping the medication on your own.[2]
Certain health conditions can make weight management much harder. Diseases like metabolic syndrome and polycystic ovary syndrome can cause side effects that include weight gain. Mental health struggles like anxiety and depression can lead people to eat high-calorie foods that activate pleasure centers in the brain, temporarily making them feel better but contributing to weight gain over time.[2]
Who Is Most at Risk?
While anyone can become overweight, certain groups face higher risks due to various factors. Understanding these patterns helps us see that becoming overweight isn’t simply about personal choices—it’s often influenced by circumstances beyond individual control.
Economic circumstances play a significant role. Poverty and food insecurity are major drivers of overweight and obesity, particularly in low- to middle-income countries and communities. When people lack access to healthy and affordable food, they’re more likely to rely on cheaper, calorie-dense processed foods. These same communities often have fewer opportunities for safe physical activity and limited access to quality healthcare. People in lower-income households also experience cycles of food deprivation and overeating, along with higher levels of stress and anxiety, all of which can promote weight gain.[21]
Race and ethnicity show clear patterns in the United States. During 2017 through March 2020, non-Hispanic Black adults had the highest obesity prevalence 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] These differences reflect complex interactions between genetics, culture, access to healthcare, neighborhood environments, and historical inequities.
Education level also correlates with obesity rates. People with a high school diploma or some college education showed the highest obesity prevalence 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] Education affects many things: understanding nutrition information, having better-paying jobs that allow for healthier food choices, and living in neighborhoods with more resources.
Regarding age, the differences aren’t as dramatic, but there are still variations. Among adults aged 20 to 39 years, 39.8% had obesity; among those 40 to 59 years, 44.3%; and among adults 60 years and older, 41.5%.[3] As people age, their body composition gradually shifts—muscle mass decreases while fat increases. This change slows down metabolism, making it easier to gain weight. Many people also become less physically active as they get older.[16]
A sedentary lifestyle increases risk considerably. High amounts of screen time—watching television, playing video games, or spending time on mobile phones and laptops—cuts into time available for physical activity. When people sit at desks all day for work without moving much, they burn fewer calories than those who are on their feet throughout the day.[4]
Not getting enough physical activity goes hand in hand with consuming calorie-dense foods. When people regularly choose fast food, processed foods, and sugary drinks while also moving very little, the risk of becoming overweight increases substantially. Additionally, consuming high amounts of salt can raise blood pressure, which becomes particularly dangerous for people already dealing with extra weight.[14]
How Overweight Affects Your Body and Health
Carrying extra weight doesn’t just change how clothes fit—it can affect virtually every system in your body, sometimes in ways you don’t immediately notice. The health consequences of being overweight are serious and wide-ranging.
One of the most significant impacts is on heart health. Overweight increases the risk of developing type 2 diabetes, heart disease, and having a stroke. Among adults with obesity in the United States, 58% have high blood pressure, which is itself a major risk factor for heart disease. Additionally, approximately 23% of adults with obesity have diabetes.[3] The connection between excess weight and these conditions is so strong that losing even a modest amount of weight can significantly reduce these risks.
Overweight affects bones and joints, particularly weight-bearing joints like knees and hips. The extra weight puts additional stress on these joints, which can lead to osteoarthritis—a painful condition where the protective cartilage that cushions joints wears down over time. This can make movement painful and reduce quality of life.[1]
Breathing and sleep can also be compromised. Sleep apnea—a condition where breathing repeatedly stops and starts during sleep—is more common in people with extra weight. This happens because excess fat around the neck and throat can obstruct airways. Poor sleep quality then contributes to other health problems and can make it harder to lose weight, creating a difficult cycle.[1]
The liver can suffer too. Excess weight increases the risk of liver disease, as fat can accumulate in liver cells even in people who drink little or no alcohol. High cholesterol levels are also more common among people who are overweight, which contributes to the buildup of fatty deposits in blood vessels, raising the risk of heart attack and stroke.[5]
Cancer risk rises with excess weight. Being overweight increases the risk of developing certain types of cancer, though the exact mechanisms aren’t fully understood. The risk appears to be related to chronic inflammation, changes in hormone levels, and effects on cell growth and division.[1]
Reproductive health and pregnancy can be affected as well. Overweight can influence hormone balance and fertility in both men and women. For women who are pregnant, starting pregnancy at an unhealthy weight increases risks for both mother and baby during pregnancy and childbirth.[5]
Quality of life takes a hit beyond physical health. Being overweight can affect a person’s ability to move comfortably, participate in activities they enjoy, and sleep well. It can also impact self-esteem and mental health. The condition influences not just how long people live, but how well they live.[1]
What You Can Do to Prevent or Address Overweight
Prevention is always easier than treatment, but it’s never too late to make changes that can improve health. Whether someone is trying to prevent becoming overweight or working to return to a healthier weight, many of the same principles apply.
Adopting a healthy eating pattern is fundamental. This doesn’t mean following restrictive fad diets or eliminating entire food groups, which rarely work long-term and can be harmful. Instead, it means choosing a balanced diet that includes plenty of fruits and vegetables, meals based on whole grains like brown rice and whole wheat bread, some dairy or dairy alternatives, lean proteins from sources like fish, poultry, eggs, and beans, and only small amounts of foods high in fat and sugar. Learning to read nutrition labels helps people understand what they’re eating and make better choices.[14]
Portion sizes matter just as much as food choices. Many people don’t realize how much they’re actually eating because portions have grown so large. Using smaller plates, measuring servings until you learn to estimate them accurately, and paying attention to hunger and fullness cues can all help with portion control.[6]
Staying physically active is equally important. Physical activity helps burn calories, builds muscle mass (which burns more calories even at rest), and improves overall health. Adults need at least 150 minutes of moderate-intensity aerobic physical activity each week—this can be broken down into 30 minutes a day, five days a week. Activities like brisk walking, cycling, swimming, or dancing all count. Adding muscle-strengthening activities at least twice a week provides additional benefits.[16]
For children and adolescents aged 6 to 17, the recommendation is 60 minutes or more of moderate-to-vigorous intensity physical activity each day. This should include aerobic activities along with muscle-strengthening and bone-strengthening exercises. For young children aged 3 to 5, being physically active throughout the day supports healthy growth and development.[16]
Getting adequate sleep is often overlooked but crucial for maintaining a healthy weight. Most adults need at least seven hours of good-quality sleep each night. Sleep affects the hormones that control hunger and appetite, so consistently missing sleep can make it much harder to maintain a healthy weight. Creating a regular sleep schedule and a calm bedtime routine can help improve sleep quality.[2]
Managing stress is another important piece of the puzzle. Chronic stress triggers the release of hormones that can increase appetite and cravings for unhealthy foods. Finding healthy ways to cope with stress—such as exercise, meditation, spending time with loved ones, or engaging in hobbies—can help prevent stress-related weight gain. Some people benefit from working with a mental health professional to develop better stress management strategies.[2]
Limiting certain foods and drinks makes a noticeable difference. Reducing consumption of added sugars, which are found in sodas, candy, baked goods, and many processed foods, can significantly decrease calorie intake without sacrificing nutrition. The same goes for foods high in saturated fat and highly processed items that are calorie-dense but nutrient-poor.[7]
Creating a supportive home environment helps everyone in the household. Keeping fresh fruits and vegetables visible and easily accessible—at eye level in the refrigerator, in a bowl on the counter—makes healthy snacking easier. Planning meals in advance and having ingredients on hand reduces the temptation to order takeout or grab fast food. When the whole family participates in preparing healthy meals and being active together, it becomes easier for everyone to maintain healthy habits.[19]
How Healthcare Providers Measure and Diagnose Overweight
When you visit a healthcare provider concerned about your weight, they use several measurements to assess your situation. The most common tool is the body mass index (BMI), which compares your weight to your height. To calculate BMI in pounds and inches, multiply your weight in pounds by 703, then divide by your height in inches, and divide again by your height in inches. Many online calculators can do this math for you.[6]
For adults, a BMI between 18.5 and 24.9 is considered a healthy weight range. A BMI of 25 to 29.9 falls into the overweight category. Once BMI reaches 30 or higher, it enters the obesity range. Obesity itself is divided into classes: Class 1 is BMI 30 to less than 35, Class 2 is BMI 35 to less than 40, and Class 3 is BMI 40 or higher. Class 3 obesity is considered severe obesity.[2]
It’s important to understand that BMI has limitations. It doesn’t directly measure body fat—it’s just an estimate based on height and weight. Some people, like muscular athletes, might have a BMI in the overweight or even obese category even though they don’t have excess body fat. That’s why healthcare providers don’t rely on BMI alone.[5]
Waist circumference provides additional information about health risks. Where you carry extra weight matters for your health. Fat stored around the waist—sometimes called visceral fat or abdominal fat—is particularly associated with increased risks of heart disease and type 2 diabetes. For women, a waist circumference of more than 35 inches, and for men, more than 40 inches, suggests higher health risks.[2]
Healthcare providers also review your complete health history. They’ll ask about your family’s health history, any medications you’re taking, your eating and exercise habits, stress levels, and sleep patterns. They’ll perform a physical exam, checking your blood pressure, heart rate, and looking for signs of health problems related to weight. If you have or are at risk for conditions like diabetes, high blood pressure, or high cholesterol, they may order blood tests to check various markers of health.[9]
For children, the criteria are different because their bodies are still growing. For children under age 5, weight-for-height measurements compared to growth standards are used. For children aged 5 to 19 years, BMI-for-age compared to growth reference standards determines if they’re overweight or have obesity.[1]
Understanding What Happens in Your Body
To really grasp why being overweight affects health so much, it helps to understand some of the changes that happen inside the body when excess fat accumulates. The body isn’t designed to carry large amounts of extra fat, and when it does, normal functions can be disrupted in multiple ways.
Your body needs some fat to function properly. Fat serves as energy storage for future needs, provides cushioning for organs, helps regulate body temperature, and plays roles in hormone production and immune function. The problem arises when fat storage becomes excessive and starts interfering with normal body processes.[8]
When you regularly consume more calories than your body uses, it converts the extra energy into stored fat. The body stores sugars as glycogen in the liver and muscles, but these storage sites have limited capacity. Once they’re full, excess energy gets converted primarily into triglycerides and stored in fat cells throughout the body. These fat cells can grow larger and the body can even create new fat cells to accommodate additional storage needs.[4]
As fat accumulates, particularly around internal organs in the abdomen, it doesn’t just sit there passively. Fat tissue actively produces substances that can trigger inflammation throughout the body. This chronic, low-level inflammation is thought to be one way that excess weight contributes to various diseases, including heart disease, diabetes, and some cancers.[5]
Excess fat, especially around the abdomen, affects how the body responds to insulin—the hormone that helps cells take up sugar from the blood. When cells don’t respond well to insulin, blood sugar levels rise, which can lead to prediabetes and eventually type 2 diabetes. The pancreas tries to compensate by producing more insulin, but over time it can’t keep up with the demand.[7]
The cardiovascular system faces increased demands when there’s excess body weight. The heart must work harder to pump blood through a larger body. Extra fat in the blood vessels can lead to atherosclerosis—a condition where fatty deposits build up inside artery walls, narrowing them and making it harder for blood to flow. This raises blood pressure and increases the risk of heart attacks and strokes.[5]
Hormones that regulate appetite and metabolism can become imbalanced. Leptin, a hormone produced by fat cells that normally signals fullness, becomes less effective when there’s too much body fat—a condition called leptin resistance. This means the brain doesn’t get clear signals about when the body has had enough food, making it easier to overeat. Other hormones involved in hunger, like ghrelin, can also be affected.[5]
The mechanical stress of carrying extra weight affects joints and bones. Weight-bearing joints experience increased pressure with every step, which accelerates wear and tear on cartilage. Over time, this can lead to painful osteoarthritis. The extra weight also puts stress on the spine and can contribute to back problems.[5]
Fat deposits around the neck and throat can physically narrow airways during sleep, leading to sleep apnea where breathing repeatedly stops and starts throughout the night. This disrupted sleep affects many aspects of health, including energy levels, concentration, mood, and even weight management itself, since poor sleep affects the hormones that control hunger.[5]
