Many people with obesity develop additional health problems known collectively as metabolic syndrome. However, not everyone with obesity has these complications. Some people call this "metabolically healthy obesity."

A person with metabolically healthy obesity has a body mass index (BMI) of over 30, but they do not have metabolic syndrome.

Metabolic syndrome consists of high blood pressure, cardiovascular disease, type 2 diabetes, and high cholesterol.

Some studies suggest that up to 35% of people with obesity do not have metabolic syndrome. In other words, they have metabolically healthy obesity.

However, some experts believe that this is misleading, as it gives the impression that obesity can be healthy.

Other experts believe that the state of metabolically healthy obesity is a passing one. In time, the person will start to develop symptoms of metabolic syndrome.

Obesity also increases the risk of other conditions, including respiratory problems and some types of cancer.

This article looks at why some people with obesity do not have metabolic syndrome, as well as what this means for their health.

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A person with metabolically healthy obesity does not have metabolic syndrome.

There are no guidelines for defining metabolically healthy obesity.

There are guidelines to define metabolic syndrome, however. Doctor will diagnose metabolic syndrome if a person has three of the following factors:

  • a waist that measures over 40 inches in men or over 35 inches in women
  • fat, or triglyceride, levels in the blood of 150 milligrams per deciliter (mg/dl) or above
  • levels of high density lipoprotein, or "good," cholesterol below 40 mg/dl in men or below 50 mg/dl in women
  • fasting blood glucose of 100 mg/dl or above
  • blood pressure of 130/85 millimeters of mercury or above

If a person has obesity but fewer than three of these factors, they have metabolically healthy obesity. However, if the person does not lose weight, the symptoms of metabolic syndrome may start to appear.

Metabolic syndrome can also affect people without obesity, but obesity is a major risk factor.

The exact link between obesity and these conditions is unclear, but inflammation appears to play a role. Experts have found that when a person with obesity loses weight, inflammation levels also tend to fall.

What treatments can help a person manage obesity?

Health professionals do not yet know why some people with obesity do not develop metabolic syndrome. Genetic factors may play a role.

In 2013, a study found that people with metabolically healthy obesity were more likely to have lower levels of inflammation than those with obesity and metabolic syndrome.

A rodent study from 2016 found that some proteins might protect the body from the harmful effects of obesity. More research is necessary to evaluate the effectiveness of these mechanisms in humans, however.

Some experts have suggested that the type of fat a person has and where it collects in the body may make a difference. Fat that collects around the lower trunk may be less harmful than fat that accumulates around the abdomen, for example.

Another team found that the bodies of metabolically healthy people burn fat more effectively than those of people with metabolic issues such as type 2 diabetes.

Lifestyle habits

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Regular exercise can improve a person's outlook.

Obesity usually results from a high energy intake and a sedentary lifestyle. That said, some people with obesity are physically active and make healthful food choices.

One study suggests that some healthful lifestyle habits can improve a person's outlook regardless of their BMI.

These habits include:

  • not smoking
  • limiting alcohol intake
  • getting 30 minutes of exercise daily
  • eating five or more servings of vegetables and fruits daily

Making healthful lifestyle choices can benefit people regardless of whether they have obesity. Also, people with obesity who follow these guidelines may have a better outcome than people with obesity who do not.

Sleep quality

In 2017, researchers revealed a difference in sleep quality between people with metabolically healthy obesity and those with metabolic syndrome.

Specifically, they found that women with metabolically healthy obesity had regular sleep disturbances, but they did not have problems with sleep duration or overall sleep quality. Those with metabolic syndrome did experience these problems.

These findings do not prove that sleep quality is a factor for metabolically healthy obesity, though it may perhaps be an indicator.

Many people with obesity have sleep apnea, which affects their breathing while they sleep. Learn more here.

Other factors

A study from 2016 found that people with metabolically healthy obesity tended to be younger, female, more likely to exercise, and less likely to smoke or drink heavily.

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A person should seek medical advice if they have obesity.

The concept of metabolically healthy obesity may help doctors provide individual treatment plans for people with obesity, but experts urge caution when using this term.

The author of a 2019 article explains that although people with metabolically healthy obesity have a lower risk of developing metabolic syndrome than those with metabolically unhealthy obesity, they still have a 50–300% higher risk of developing it than those without obesity.

Also, around half of those with metabolically healthy obesity will develop symptoms of metabolic syndrome within around 10 years. For this reason, it is important for people with obesity to seek medical advice.

A person with metabolically healthy obesity is unlikely to have the same outlook as a person without obesity. This is because metabolic syndrome is not the only health concern that can arise from obesity.

People with a high BMI are more likely to develop a wide range of complications, including musculoskeletal problems, asthma, sleep apnea, some cancers, reproductive problems, depression, and many others.

For this reason, anyone with obesity should speak to their doctor for advice. The doctor will likely suggest making an action plan to reduce the person's BMI.

Q:

If a person has obesity but no metabolic symptoms, is this just because they only recently developed obesity? Or is it possible for someone to live with obesity and not have metabolic syndrome?

A:

Research suggests that people with metabolically healthy obesity have a higher risk of developing metabolic abnormalities than people who do not have obesity. Genetics and lifestyle certainly play a role. However, it is hard to determine if everyone with metabolically healthy obesity will eventually develop metabolic problems. In time, it is possible that everyone with obesity will have metabolic issues if they do not lose weight.

That said, many people do live their whole life never progressing beyond metabolically healthy obesity. Scientists need to conduct more research to determine the risks and causes associated with metabolic syndrome.

Kevin Martinez, MD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.