What is obesity and overweight?

When you want to lose weight: Overview

If you want to lose weight, eating a healthy diet and being more active can help. Changing how you think and finding support also can help. You may want to work with your doctor to make a weight-loss plan that's right for you.


Obesity means having an unhealthy amount of body fat. This puts your health in danger.

Obesity puts you at greater risk for type 2 diabetes, heart disease, high blood pressure, arthritis, sleep apnea, some types of cancer, and stroke.

Treatment involves a long-term plan for making lifestyle changes. Medicine or surgery is sometimes used.

What happens when a person is obese?

Obesity can raise your risk for certain health problems. These may include type 2 diabetes, high blood pressure, coronary artery disease (CAD), and stroke. If you have healthier habits or lose weight, you can lower your risk for these conditions.

Obesity: Can you take medicines or have surgery to lose weight?

If you have a BMI in a certain range and have not been able to lose weight with diet and exercise, medicine or surgery may be an option for you.

If you have a BMI of at least 30.0 (or a BMI of at least 27.0 and another health problem related to your weight), ask your doctor about weight-loss medicines. They work by making you feel less hungry, making you feel full more quickly, or changing how you digest fat. Medicines are used along with diet changes and more physical activity to help you make lasting changes.

If you have a BMI of 40.0 or more (or a BMI of 35.0 or more and another health problem related to your weight), your doctor may talk with you about surgery. Weight-loss surgery has risks, and you will need to work with your doctor to compare the risk of having obesity with the risks of surgery.

With any option you choose, you will still need to eat a healthy diet and get regular exercise.

How do you know if your weight is in the obesity range?

To know if your weight is in the obesity range, your doctor looks at your body mass index (BMI) and waist size.

BMI is a number that is calculated from your weight and your height. To figure out your BMI for yourself, you can use an online tool, such as http://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm on the National Institutes of Health website.

If your BMI is 30.0 or higher, it falls within the obesity range. Keep in mind that BMI and waist size are only guides. They are not tools to determine your ideal body weight.

How can you stay on your plan for change?

Be ready. Choose to start during a time when there are few events like holidays, social events, and high-stress periods. These events might trigger slip-ups.

Decide on your first few steps. Most people have more success when they make small changes, one step at a time. For example, you might switch a daily candy bar to a piece of fruit, walk 10 minutes more, or add more vegetables to a meal.

Line up your support people. Make sure you're not going to be alone as you make this change. Connect with people who understand how important it is to you. Ask family members and friends for help in keeping with your plan. And think about who could make it harder for you, and how to handle them.

Try tracking. People who keep track of what they eat, feel, and do are better at losing weight. Try writing down things like:

  • What and how much you eat.
  • How you feel before and after each meal.
  • Details about each meal (like eating out or at home, eating alone, or with friends or family).
  • What you do to be active.

Look and plan. As you track, look for patterns that you may want to change. Take note of:

  • When you eat and whether you skip meals.
  • How often you eat out.
  • How many fruits and vegetables you eat.
  • When you eat beyond feeling full.
  • When and why you eat for reasons other than being hungry.

When you stray from your plan, don't get upset. Figure out what made you slip up and how you can fix it.

How do your genes put you at risk of being overweight?

Genes determine what features (genetic traits) you inherit from your parents. They influence your weight by their effect on:

How your body uses calories (energy metabolism).
Some people need fewer calories to fuel their bodies. They may have "leftover" calories that are stored as fat. Other people need more calories to fuel their bodies. They have fewer leftover calories to store as fat.
Basal metabolic rate (BMR).
BMR is how much energy you burn when you're at rest. If you have a lower BMR, it's easier to gain weight.
Body signals.
Hunger, fullness (satiety), and appetite are body signals that tell you how much to eat.
Set point.
Your body may try to keep your weight within a specific range, or set point.
Fat distribution.
Men tend to store fat in the belly, while women store more in the hips and thighs. As women age, more fat is stored in the belly.

What is obesity?

Obesity means having an unhealthy amount of body fat. This puts your health in danger. It can lead to other health problems, such as type 2 diabetes and high blood pressure.

What causes obesity?

When you take in more calories than you burn off, you gain weight. How you eat, how active you are, and other things affect how your body uses calories and whether you gain weight.

If you have family members who have too much body fat, you may have inherited a tendency to gain weight. And your family also helps form your eating and lifestyle habits, which can lead to obesity.

Also, our busy lives make it harder to plan and cook healthy meals. For many of us, it's easier to reach for prepared foods, go out to eat, or go to the drive-through. But these foods are often high in saturated fat and calories. Portions are often too large.

Obesity: What can you do to reach a healthy weight?

Focus on health, not diets. Diets are hard to stay on and don't work in the long run. It is very hard to stay with a diet that includes lots of big changes in your eating habits.

Instead of a diet, focus on lifestyle changes that will improve your health and achieve the right balance of energy and calories. To lose weight, you need to burn more calories than you take in. You can do it by eating healthy foods in reasonable amounts and becoming more active, even a little bit every day. Making small changes over time can add up to a lot.

Make a plan for change. Many people have found that naming their reasons for change and staying focused on their plan can make a big difference. Work with your doctor to create a plan that is right for you.

  • Ask yourself: "What are my personal, most powerful reasons for wanting this change? What will my life look like when I've made the change?"
  • Set your long-term goal. Make it specific, such as "I will lose x pounds."
  • Break your long-term goal into smaller, short-term goals. Make these small steps specific and within your reach, things you know you can do. These steps are what keep you going from day to day.

Talk with your doctor about other weight-loss options. If you have a BMI in a certain range and have not been able to lose weight with diet and exercise, medicine or surgery may be an option for you. Before your doctor will prescribe medicines or surgery, he or she will probably want you to be more active and follow your healthy eating plan for a period of time. These habits are key lifelong changes for managing your weight, with or without other medical treatment. And these changes can help you avoid weight-related health problems.

©2011-2024 Healthwise, Incorporated

The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.