Having a higher body weight doesn’t automatically mean a person is unhealthy. Metabolically healthy obesity (MHO) is a term for when a person has been diagnosed with obesity, but they don’t have any of the health issues typically associated with higher body fat.

While it may seem like a positive thing that some people can carry extra body weight and not have it affect their health, the truth can be a little more complicated. Some people may have a larger body size and also stay metabolically healthy, because of genetics or a commitment to physical activity and fresh, whole food choices that support their overall wellness. Other people diagnosed with MHO may face increased risks for cardiovascular disease or diabetes later in life, especially if their weight or lifestyle changes.

If you’re curious about what MHO really means, this article explains it in a straightforward way to help you understand what’s going on in your body. Then, you and your doctor can talk about the best ways to stay healthy and lower your chances of future problems.

What Is Metabolically Healthy Obesity?

Part of the confusion around metabolically healthy obesity is that there’s no single, standardized definition of what the term means. In some research, MHO is defined as having an obesity diagnosis based on a body mass index (BMI) over 30 while also having either zero, one, or two other signs of metabolic syndrome. Metabolic syndrome is a group of health problems that includes hypertension (high blood pressure), high blood glucose (blood sugar) levels, and dyslipidemia (abnormal levels of fats in your blood).

Other studies count people as having metabolically healthy obesity if they don’t have signs of insulin resistance. Still others define it as having normal glucose and lipid (fat) levels and not having high blood pressure.

Keep in mind that there are many definitions of metabolically healthy obesity, and doctors haven’t fully agreed on a single definition yet. Since some definitions focus only on one or two specific aspects of metabolic health, a person could be healthy in those aspects and not in others that aren’t measured. Describing someone as metabolically healthy could be misleading without looking at the full spectrum of possible metabolic dysfunction and other determinants of health.

Metabolically Healthy Obesity vs. Preclinical Obesity

Preclinical obesity is a newer term that can be helpful in this conversation. It’s usually used to describe someone with obesity whose organs and tissues are functioning normally when tested. People who are diagnosed with preclinical obesity are still considered to have a higher risk of developing certain health conditions than those without obesity. These include:

• Type 2 diabetes
• Some kinds of cancer
• Certain mental health issues
• Cardiovascular disease

Preclinical obesity may be a more useful term than metabolically healthy obesity because it shows how doctors can look at more than just metabolism when checking someone’s health. For example, a person might have problems with their muscles, joints, or lungs — parts of the body that aren’t usually linked to metabolism. Even if their metabolism looks normal, they may still have early signs of illness that could benefit from treatment.

Are There Long-Term Risks to Metabolically Healthy Obesity?

There’s some confusion, too, over whether people diagnosed with MHO are still at a higher risk of developing complications often linked with obesity. Some of this confusion may occur because researchers have different definitions of the term.

However, regardless of the definition, some people do live with obesity, and it doesn’t affect them metabolically in any other way. While researchers don’t know exactly what conditions lead to this kind of obesity, it seems connected to a few things in the body. Those include:

• Less fat around the organs and the liver
• A body fat distribution and body composition with more fat deposited in the legs than in the center of the body
• A higher level of cardiovascular fitness
• A biological ability to store more fat than other people can
• Less inflammation throughout the body

It’s important to note that someone may qualify for a diagnosis of metabolically healthy obesity or preclinical obesity at one point, then not qualify for it later on. In fact, under most definitions of MHO, people have a higher risk of cardiovascular disease (heart disease) later in life. If they develop these issues, they may not be considered metabolically healthy or to have preclinical obesity.

Since these results show up most clearly in long-term studies, it’s important to keep track of what’s going on in your body so you don’t get caught off guard. Even if you don’t experience a major cardiovascular event like a stroke or heart failure, you may move toward metabolically unhealthy obesity. In one study, almost half of the people highlighted as metabolically healthy developed metabolic complications over a period of 10 years.

Monitoring Metabolically Healthy Obesity

One of the best things you can do to take charge of your health is to work with a healthcare provider to get regular monitoring. They can order tests to look at all aspects of your metabolic systems. These results give you a comprehensive picture of what’s happening in your body. If the results show you are moving toward being less healthy, you’ll know it’s time to take different actions to try and improve your health.

Different doctors may assess metabolic health in different ways. In general, they’ll look at factors like:

• Fasting blood glucose levels
• HDL or “good” cholesterol levels
• LDL or “bad” cholesterol levels, as well as total cholesterol
• Blood pressure
• Triglyceride levels
• Waist circumference

If your doctor wants more details, they may ask for tests that look at how well your kidneys and liver are working, your overall cholesterol levels, your inflammation levels, and more. These are usually straightforward blood tests. You'll need to fast to get accurate results on some of them. Your doctor will let you know if you need to do this.

Talk to Your Doctor

If you want to better understand the link between metabolic health and obesity-related conditions like metabolic syndrome, talk to your doctor today. They can help you assess your current metabolic health and make a plan to improve it or keep it going strong, which may lower your risk of health problems.

Your doctor can also help you figure out aspects of your life that might be contributing to obesity. These can include:

• Cultural factors
• How much family support you have
• The level of physical activity you do every day
• Whether you turn to food for emotional regulation
• Whether you have other conditions that make it hard to maintain a balanced weight, like hypothyroidism
• Whether any medication you’re taking can lead to weight gain, such as corticosteroids or certain antidepressants

Understanding this can help you take steps toward improving your health, regardless of your current metabolic status.

Finally, your doctor will be key in monitoring your ongoing health and helping with weight loss. They can order the tests noted above so you can understand what’s going on in your body.

Talk With Others Who Understand

On MyObesityTeam, the social network for people with obesity and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with obesity.

Have you and your doctor talked about your metabolic health? Have you been diagnosed with preclinical obesity? Share your experience in the comments below, or start a conversation by posting on your Activities page.