Can you be healthy while obese?

SadaNews - Two individuals may share the same age, weight, and body mass index, yet their health conditions can differ drastically. One might suffer from high blood pressure, elevated blood sugar, and high triglycerides, along with fat accumulation in the liver, while the other’s tests may fall within normal ranges and show no apparent disorders.

However, similar weight does not imply similar health risks, and normal test results do not provide complete or permanent protection against obesity-related complications.

This led to the emergence of the term "metabolically healthy obesity" in medical literature to describe individuals with a clear excess of fat but who, at the time of assessment, do not suffer from common metabolic disorders such as insulin resistance, diabetes, hypertension, or dyslipidemia.

However, the term has sparked extensive scientific debate: Does truly healthy obesity exist, or is it merely a temporary stage before disease manifests?

The scale doesn’t reveal everything

Obesity in adults is traditionally defined by a body mass index (BMI) of 30 kilograms per square meter or more, calculated by dividing weight in kilograms by the square of height in meters.

However, the BMI is just a tool for initial screening and does not provide a complete diagnosis of health status. It does not distinguish between fat and muscle, nor does it specify where fat accumulates, or whether it has started to affect organ functions.

This is why an international committee that published its recommendations in The Lancet Diabetes & Endocrinology in 2025 emphasized that reliance on BMI alone for diagnosing obesity should be avoided.

The committee recommended confirming fat excess through additional measurements, such as waist circumference, waist-to-height ratio, body composition measurements, and then examining the effects of accumulated fat on organ functions and daily life.

Thus, the medical question goes beyond how much a person weighs to include where fat accumulates and how it affects the body.

What does metabolic health mean?

There is currently no universally accepted definition of metabolically healthy obesity, which explains the variation in study results and the prevalence rates of this condition.

Researchers typically look at a range of indicators, including:

Blood pressure.

Fasting blood sugar.

Glycated hemoglobin.

Triglycerides.

High-density lipoprotein (HDL) cholesterol.

Insulin resistance.

Use of diabetes, blood pressure, or dyslipidemia medications.

History of cardiovascular disease.

A person might be classified as metabolically healthy in some studies if they do not suffer from any of these disorders, while other studies allow for one risk factor, and sometimes two.

Therefore, one may self-categorize as metabolically healthy obesity based on one definition while being deemed unhealthy according to another. The more lenient the criteria, the higher the proportion of individuals categorized in this group, and vice versa.

Additionally, normal test results on a specific day do not indicate the absence of all early effects of obesity, as changes within the liver, blood vessels, or adipose tissue may begin before blood sugar or pressure reach levels that warrant a disease diagnosis.

Not all fats are alike

Obesity cannot be understood by considering fat as a single mass. The location of fat storage and how the body manages it may be more crucial than the absolute quantity.

Adipose tissue can be likened to an energy reservoir. When this reservoir is well-equipped to expand, it can store fat under the skin more safely, reducing leakage into organs not designed to hold large quantities.

However, when fat cells enlarge, experience stress, and lose their ability to store additional energy, fatty acids begin to enter the bloodstream and accumulate in the liver, muscles, pancreas, and around internal organs.

This accumulation contributes to inflammation, insulin resistance, and lipid and sugar disorders. Therefore, visceral fat surrounding abdominal organs, and fat in the liver and muscles, pose greater metabolic risks than subcutaneous fat, particularly in the hips and thighs.

Many metabolically healthy obese individuals tend to possess lower amounts of visceral fat and liver fat, better insulin sensitivity, less inflammation in adipose tissue, and higher cardiorespiratory fitness than others with the same BMI.

These differences are influenced by various factors, including genetics, age, sex, physical activity, sleep, diet, and fitness, along with the fat cells' ability to expand without losing their function.

Why are scientists studying this condition?

Researchers do not study metabolically healthy obesity solely to classify obese individuals, but to understand why some people resist complications despite having large amounts of fat.

The question extends beyond why some obese individuals develop diabetes, fatty liver disease, and heart diseases, but also includes identifying the factors that protect others with similar levels of obesity, even if only for a limited time.

Research indicates that metabolically healthy obese individuals may have a better ability to create new, small fat cells that store energy safely rather than continuing to enlarge existing cells until they lose function.

They also typically have less visceral fat, liver fat, better insulin sensitivity, and less inflammation and fibrosis within adipose tissue, as well as higher levels of beneficial hormones like adiponectin.

Scientists are also investigating blood flow within adipose tissue, the functions of mitochondria responsible for energy production, and the fat's ability to remain in its natural storage rather than migrating to the liver, muscles, and pancreas.

Genome, protein, metabolite, and microRNA studies are exploring the molecular differences that may explain this metabolic flexibility.

Understanding these mechanisms may pave the way for developing treatments that improve adipose tissue's ability to store fat, reduce inflammation and fibrosis, limit the migration of fat to organs, or restore insulin sensitivity in the future.

However, caution is required, as some molecular differences may be a result of protection rather than a cause, and no discovery can be turned into treatment until its ability to genuinely alter disease progression is proven.

Is it less hazardous?

Generally, metabolically healthy obese individuals tend to have better health and a lower risk of developing diabetes and heart disease compared to those facing obesity along with elevated pressure, sugar levels, and dyslipidemia. However, when compared to individuals of normal weight and good metabolic health, the results are less reassuring.

Studies have indicated that the risks of diabetes and heart disease, particularly heart failure, may remain elevated among those with obesity, even when their metabolic tests are initially normal.

One study tracked over 381,000 participants in the UK Biobank for an average of over 11 years. It found that metabolically healthy obesity was associated with increased risks of diabetes, heart disease, heart failure, respiratory diseases, and early death when compared to those of normal weight with good metabolic health.

These findings do not mean that every obese person will develop these diseases but indicate a higher statistical likelihood within a large group.

Not all research has reached the same conclusion. A review published in Nature Reviews Endocrinology in 2024 indicated that the risk of heart disease rises moderately when using traditional definitions of metabolically healthy obesity, but may approach risks similar to those of normal-weight individuals when applying strict criteria that consider fat distribution and risk factors.

This does not establish that obesity is safe, but affirms that individuals with obesity do not constitute a single healthy group, and estimating risk should not rely solely on weight.

Today's health does not guarantee tomorrow's

Metabolically healthy obesity is not always a stable condition. Some individuals may maintain their metabolic health for years, while others gradually progress to insulin resistance, dyslipidemia, or elevated blood pressure and diabetes.

In a large study conducted on adults in China, about 40% of overweight or obese individuals who were metabolically healthy transitioned to an unhealthy status during the follow-up period, and this shift was associated with a significant increase in the risk of cardiovascular events.

The likelihood of this transition rises with visceral and liver fat accumulation, advanced age, low activity levels, decreased fitness, sleep disturbances, weight gain, and genetic predisposition.

Thus, describing "obesity without metabolic disorders currently" may be more accurate than the term "healthy obesity," which could create a false sense of security.

Tests do not detect all complications

Most definitions of metabolic health focus on sugar, pressure, cholesterol, and triglycerides, but may overlook other obesity-related issues, including:

Obstructive sleep apnea.

Joint pain and mobility issues.

Fertility disorders.

Gastroesophageal reflux.

Certain gallbladder diseases.

Some cancers.

A person may have normal blood pressure and blood sugar yet struggle with mobility or experience sleep apnea, thus cannot be deemed fully healthy.

A pooled European study revealed that obesity is associated with an elevated risk of several weight-related cancers even with normal metabolic indicators, although the risk is higher among those combining obesity with metabolic disorders.

The "Lancet" international committee suggested dividing obesity into two more accurately defined categories. The first is "clinical obesity," meaning that excess fat has indeed caused organ dysfunction or symptoms limiting daily activity, such as heart failure, obstructive sleep apnea, liver and kidney damage, or mobility difficulties.

"Preclinical obesity," on the other hand, refers to the confirmed presence of excess fat while organ functions remain preserved at present, but with an increased risk of disease in the future.

This classification is broader than the concept of metabolically healthy obesity, as metabolic tests may appear normal, but the presence of a functional issue related to obesity moves the individual into the clinical obesity category.

What to do if your tests are normal?

Normal test results are good news, but they do not eliminate the need for monitoring. A health assessment should include:

Waist circumference and its changes over time.

Blood pressure, blood sugar, and glycated hemoglobin.

Triglycerides and cholesterol.

Liver health and the possibility of fat accumulation within it.

Symptoms of obstructive sleep apnea.

Cardiorespiratory fitness and mobility.

Family history of diabetes and heart disease.

Smoking, sleep, activity, and food quality.

Not all individuals with obesity require the same degree of treatment, as the need for intervention is greater for those suffering from diabetes, hypertension, fatty liver disease, or clear organ dysfunction.

However, regular physical activity, balanced food intake, adequate sleep, improved fitness, and preventing continual weight gain remain beneficial for everyone.

Insulin sensitivity, blood pressure, liver fat, and fitness can improve before a significant change occurs in weight. At the same time, it is essential to avoid stigmatizing individuals or reducing their health and worth to their weights, as stigma may drive some away from seeking medical care.

Temporary health does not guarantee ongoing safety

A person may be obese without currently suffering from diabetes, hypertension, or dyslipidemia, and their health may be much better than that of another individual with the same weight who has multiple metabolic disorders.

But this does not mean that obesity is harmless, nor does it guarantee continued metabolic health in the future. Risks are influenced by the location of fat accumulation, the health of adipose tissue, fitness, age, genetics, and any organ damage that may not be revealed by routine tests.

Obesity is not an immediate verdict of disease, but normal tests are not a permanent passport to safety. The more accurate statement is that a person may currently be obese and metabolically healthy, but maintaining this health requires a balanced lifestyle, regular monitoring, and medical evaluations that go beyond the scales.

Source: Al Jazeera