Obesity

What is obesity?

Obesity is when you have excessive body fat. It’s a chronic (long-term) and complex disease that can affect your overall health and quality of life. Obesity can lead to serious medical conditions. It can affect your self-esteem and mental health.

If you have obesity, you’re not alone. It’s a common disease that affects 2 in 5 adults in the United States. A healthcare provider can help you find the treatments and management strategies for your body and health.

What are the symptoms of obesity?

While obesity is a disease, it doesn’t cause specific symptoms. A healthcare provider may define obesity by calculating your:

• Body mass index: The BMI measures average body weight against average body height. Healthcare providers use BMI to classify obesity.
• Body shape: Providers may measure your waist circumference.

BMI classifications

Healthcare providers classify obesity by your BMI. There are three general classes of obesity that providers use to decide what steps you can take to lose weight. Those classes are:

• Class I obesity: BMI 30 to less than 35 kg/m² (kilograms per square meter).
• Class II obesity: BMI 35 to less than 40 kg/m².
• Class III obesity: BMI 40+ kg/m².

When you think about the BMI scale, it’s important to remember the BMI scale doesn’t accurately predict specific health risks.

Waist circumference

Where you carry extra weight may be a sign that you have more risk of health issues that obesity may cause. The U.S. Centers for Disease Control and Prevention (CDC) says a waist circumference of more than 35 inches in people assigned female at birth (AFAB) or 40 inches in people assigned male at birth (AMAB) can be a risk factor for cardiovascular disease or Type 2 diabetes.

What causes obesity?

On the most basic level, obesity happens when you consume more calories than your body can use. Many things may play a role in why you may eat more food than your body needs:

• Certain medications: Medications you take to treat other conditions may contribute to weight gain. Examples are antidepressants, steroids, anti-seizure medications, diabetes medications and beta-blockers.
• Disability: Adults and children with physical and learning disabilities are most at risk for obesity. Physical limitations and lack of adequate specialized education and resources can contribute.
• Eating habits: Consuming more calories than your body needs, eating ultra-processed food, high-sugar foods and drinks, and foods with high amounts of saturated fat may cause overweight.
• Genetics: Research shows people with obesity carry specific genes (obesity-susceptibility genes) that affect appetite. It’s not clear if people with overweight have the same genetic makeup.
• Lack of physical activity: High amounts of screen time — like watching TV, playing video games or spending time on your mobile phone or laptop — cut into the time you have for physical activity.
• Lack of sleep: Missing out on at least seven hours of sleep can affect the hormones that keep hunger urges under control.
• Stress: Your brain and body react to stress by making more hormones like cortisol that manage hunger. When you’re stressed, you’re more likely to eat high-fat, high-sugar food (comfort food) that your body stores as extra fat.
• Underlying health issues: Diseases like metabolic syndrome and polycystic ovary syndrome can cause side effects like weight gain. Mental health issues like anxiety and depression can lead to eating high-calorie foods that activate the pleasure centers in your brain.

What are the complications of obesity?

Obesity affects your body in many ways. For example, it may cause metabolic changes that increase your risk of serious illnesses. Obesity may also have direct and indirect effects on your overall health.

Metabolic changes

Your metabolism is how your body converts calories into energy to fuel your body. When your body has more calories than it can use, it converts the extra calories into lipids and stores them in your body fat. When you run out of tissue to store lipids, the fat cells themselves become enlarged. Enlarged fat cells secrete hormones and other chemicals that cause inflammation.

Inflammation can lead to insulin resistance so your body can’t use insulin to lower the sugar and fats in your blood. High levels of sugar and fats in your blood lead to high blood pressure. Combined, these conditions lead to metabolic syndrome. Metabolic syndrome is a common factor in obesity. The syndrome also increases your risk of developing diseases like:

• Cardiovascular diseases: Having obesity increases your risk for cardiovascular diseases, including coronary artery disease, congestive heart failure, heart attack and stroke.
• Fatty liver disease: Excess fats circulating in your blood make their way to your liver, which is responsible for filtering your blood. When your liver begins storing excess fat, it can lead to chronic liver inflammation (hepatitis) and long-term liver damage (cirrhosis).
• Gallstones: Higher blood cholesterol levels can cause cholesterol to accumulate in your gallbladder, which increases your risk of cholesterol gallstones and gallbladder diseases.
• Kidney disease: High blood pressure, diabetes and liver disease are among the most common contributors to chronic kidney disease.
• Type 2 diabetes: Having obesity specifically raises your risk of Type 2 diabetes.

Statistically, obesity increases your risk of premature death from all causes. Studies show you can reduce that risk by losing even a small amount (5% to 10%) of your current weight.

Direct effects

Excess body fat can crowd the organs of your respiratory system and put stress and strain on your musculoskeletal system. This contributes to:

• Arthritis.
• Asthma.
• Back pain.
• Obesity hypoventilation syndrome.
• Sleep apnea.

Having obesity increases your risk of conditions and diseases like:

• Certain cancers, including esophageal, pancreatic, colorectal, breast, uterine and ovarian.
• Depression and mood disorders.
• Female infertility and pregnancy complications.
• Issues with memory and cognition, including a heightened risk of Alzheimer’s disease and dementia.

How do healthcare providers diagnose obesity?

Your healthcare provider will measure your weight, height and waist circumference at your appointment. They may do body composition tests like a bone density test scan or a bioelectrical impedance analysis. This test measures body composition based on the rate at which an electrical current passes through your body. More importantly, they’ll want to know about your overall health. They’ll ask about:

• Your history of medical conditions and treatments, including medications. They may ask about your biological family’s health.
• Your weight history, including your experience with any weight management strategies that you’ve tried.
• Your lifestyle, including your current eating habits, how you sleep and how much activity you do in your daily life.
• Your mental well-being. They may ask about stress and other things that could affect your mental well-being. Stress and other issues can lead to eating more.

Your provider will also examine your vital signs, and they may order certain blood tests. They’ll use this complete profile to diagnose obesity and any related conditions you might have.

How is obesity treated?

Your healthcare provider will work with you to find a weight loss plan that works for you. Since everyone is different, it may take some trial and error to figure out which therapies work best:

• Changing what you eat: You’re unique. That means you should tailor any change in what you eat to what works for you. There are ways to make meals packed with healthy food. Your provider can suggest scientifically proven eating plans like the Mediterranean diet or the DASH diet. These aren’t like other diets that have restrictive, negative aspects. They’re more like a set of positive guidelines that can help you meet your nutrition goals.
• Building activity into your day: Activity burns off calories and there are many ways to boost your activity
• Mental health support: Counseling, support groups and cognitive behavioral therapy (CBT) can help support positive changes. They can also help you manage stress and address emotional and psychological factors that may be working against you.

Medication for weight loss

Your healthcare provider may recommend that you add medication to your weight loss plan. Medications aren’t the whole answer to weight loss, but they can help tackle it from another angle. For example, appetite suppressants can intercept some of the pathways to your brain that affect your hunger. The following drugs have U.S. Food and Drug Administration (FDA) approval as obesity treatments:

• Bupropion-naltrexone (Contrave^®): May reduce cravings and food intake.
• GLP-1 agonists: Controls appetite, makes you feel full earlier and may lower your blood sugar. Ozempic^® is an example of a GLP1 agonist.
• Semaglutide (Wegovy^®) and/or tirzepatide (Zepbound^®): Suppresses appetite. Providers may combine this medication with a GLP-1 agonist.
• Liraglutide (Saxenda^®): Reduces appetite and slows digestion.
• Orlistat (Xenical^®, Alli^®): Reduces absorption of fat from your gut.
• Phentermine-topiramate (Qsymia^®): Makes you less hungry.
• Phentermine (Adipex-P^®, Lomaira^®, Suprenza^®): Decreases your appetite. It’s approved for use for three months at a time.

Weight loss surgery

If you have class III obesity, bariatric surgery may be an option for you. Bariatric surgery procedures work by changing your digestive system — usually your stomach, and sometimes also your small intestine — to regulate how many calories you can consume and absorb. They can also reduce the hunger signals that travel from your digestive system to your brain. Bariatric surgeries include:

• Duodenal switch.
• Gastric band (LAP band).
• Gastric bypass (Roux-en-Y).
• Gastric sleeve (sleeve gastrectomy).

Can obesity be prevented?

Preventing obesity is easier than treating it once it’s taken hold. That’s because your body manages your body mass by shifting gears as it balances your hunger signals against the amount of energy you use from your daily activity. Once your body establishes a new high “set point," it considers that to be your new baseline weight. That new set point may put your weight higher on the scale or the BMI table. Examining your habits and making reasonable changes now can help you prevent future obesity. Here are some examples:

• Make small changes: Do you have a daily snack habit or “pick-me-up,” such as a sugary drink, which is high in calories? Consider replacing it. Just 150 extra calories a day can add up to 10 extra pounds in a year. That’s equal to a snack-size bag of potato chips, or just two double-stuffed sandwich cookies.
• Add physical activity: Alternatively, consider what you might do to spend an extra 150 calories in a day by finding an activity that’s right for you and your fitness level.
• Shop intentionally: Stock your home with healthy foods and save sweets and treats for special occasions when you go out.
• Cultivate overall wellness: Reduce your screen time, go outside and get some fresh air. Manage your stress and try to get adequate sleep to keep your hormone levels in check. Focus on positive changes and healthy activities rather than how your efforts affect your weight.

What can I expect if I have obesity?

Having obesity increases your risk of some serious medical conditions. But having obesity doesn’t mean you have those conditions or there’s nothing you can do to prevent them. Remember, weight loss of just 5% to 10% can significantly improve your health risks. Sticking with a long-term treatment plan can help you maintain weight loss.

What can I do to avoid regaining lost weight?

You may think your weight loss journey ends when you reach a certain weight. But obesity is a chronic disease. That means you’ll need to continue the steps you took to lose weight, like shopping intentionally and being active several days a week.