A person can feel perfectly healthy while changes taking place inside their body gradually increase their risk of heart disease, stroke, diabetes and other chronic illnesses.
That is part of what makes metabolic risks particularly concerning.
Unlike an infection that may quickly cause fever or pain, conditions such as high blood pressure, elevated blood glucose, excess body weight and abnormal cholesterol can develop slowly, sometimes without obvious warning signs.
The World Health Organization identifies four major metabolic risk factors associated with noncommunicable diseases: raised blood pressure, overweight and obesity, raised blood glucose and abnormal blood lipids, including high cholesterol.
Together, these factors contribute to some of the world's biggest health challenges, particularly cardiovascular disease and diabetes.
A health problem that can remain hidden
High blood pressure illustrates the problem.
A person with hypertension can go for years without experiencing noticeable symptoms. Unless their blood pressure is measured, they may not know anything is wrong.
WHO estimates that about 1.4 billion adults aged between 30 and 79 were living with hypertension globally in 2024. Around 44 per cent were unaware they had the condition.
Only about 23 per cent of adults with hypertension had it under control.
Uncontrolled high blood pressure gradually places additional strain on blood vessels and organs. Over time, it can contribute to heart disease, stroke and kidney damage.
High blood sugar can present a similar challenge. Type 2 diabetes may develop gradually, and some people live with elevated blood glucose before receiving a diagnosis.
The longer metabolic abnormalities remain undetected or poorly controlled, the greater the potential for long-term health complications.
Obesity has become a global challenge
Rising levels of overweight and obesity are another important part of the metabolic health picture.
WHO estimates show that 2.5 billion adults worldwide were overweight in 2022, including approximately 890 million living with obesity.
About 43 per cent of adults were overweight and 16 per cent were living with obesity.
The change over several decades has been substantial. Global adult obesity prevalence has more than doubled since 1990.
Obesity is associated with an increased risk of several chronic conditions, including cardiovascular disease, type 2 diabetes and some cancers.
Importantly, obesity is no longer considered exclusively a problem affecting wealthy countries.
Low and middle-income countries increasingly face what health experts describe as a double burden of malnutrition. Undernutrition remains a problem in some communities while overweight, obesity and diet-related chronic diseases rise at the same time.
What is driving metabolic risk?
There is no single explanation.
Genetics, ageing and existing medical conditions can influence an individual's risk, but lifestyle and environmental factors also play significant roles.
Modern lifestyles can involve long periods of sitting, less physical activity, highly processed foods and diets containing excessive amounts of salt, sugar and unhealthy fats.
Urbanisation can also change how people work, travel and eat.
Someone who previously walked considerable distances may begin commuting by vehicle and working at a desk for most of the day. Convenience foods may become easier to obtain than healthier alternatives, while demanding working schedules can make regular exercise difficult.
These changes can appear small individually.
Repeated over months and years, however, they can contribute to weight gain, higher blood pressure, abnormal blood glucose and unhealthy cholesterol levels.
Tobacco use and harmful alcohol consumption add further health risks.
This is why metabolic health cannot be reduced to individual willpower alone. Food affordability, working environments, neighbourhood safety, access to recreational spaces and healthcare all influence the choices available to people.
Younger adults should not assume they are protected
Chronic diseases are often associated with old age, but the biological processes behind them can begin much earlier.
Weight gain, elevated cholesterol, rising blood pressure and insulin resistance can emerge during adulthood long before serious complications occur.
This makes prevention important even for people who feel healthy.
A young professional spending most of the day behind a computer, regularly eating highly processed food and getting little physical activity may be accumulating health risks without experiencing immediate symptoms.
The absence of symptoms is therefore not necessarily evidence that everything is normal.
The numbers matter
Understanding metabolic health often begins with basic measurements.
Blood pressure can reveal hypertension. Blood glucose testing can help identify diabetes or abnormal glucose regulation. Cholesterol testing provides information about blood lipids, while body weight and other clinical assessments can help healthcare professionals evaluate obesity-related risk.
No single measurement tells the entire story.
Risk can also depend on age, family history, smoking, existing medical conditions and other factors, which is why results should be interpreted in an appropriate clinical context.
Regular health checks become particularly important because several metabolic abnormalities can be managed more effectively when identified early.
Prevention does not require perfection
Reducing metabolic risk does not necessarily require an extreme diet or intense exercise programme.
Regular physical activity, maintaining a healthy weight, avoiding tobacco, moderating alcohol consumption and eating a balanced diet can contribute to better metabolic health.
Dietary patterns also matter.
Reducing excessive salt consumption can help with blood pressure, while limiting foods high in added sugars, saturated fats and trans fats can form part of a healthier overall diet.
Fruit, vegetables, whole grains, legumes and other nutrient-rich foods can play an important role within a balanced diet.
Sleep and stress should not be ignored either. Metabolic health reflects a complex interaction between behaviour, biology and environment rather than a single food or habit.
For people already diagnosed with hypertension, diabetes or other metabolic conditions, lifestyle changes may form only part of treatment. Medication and continued medical care may also be necessary.
The consequences extend beyond individual health
Rising metabolic risks eventually affect entire health systems.
When more people develop diabetes, cardiovascular disease, kidney disease and other chronic conditions, demand increases for medication, hospital care, laboratory testing and long-term treatment.
Families can also face years of healthcare expenses and lost income when chronic illness reduces a person's ability to work.
This makes prevention economically important as well as medically important.
Countries that once concentrated much of their healthcare resources on infectious diseases increasingly have to manage infectious illnesses and chronic noncommunicable diseases simultaneously.
Small warning signs should not be the starting point
Perhaps the most important lesson about metabolic health is that people should not necessarily wait until they feel sick before paying attention.
Hypertension is frequently symptomless. High cholesterol can also exist without obvious symptoms, while abnormal blood glucose can develop gradually.
By the time complications such as heart disease, stroke or serious diabetes-related problems appear, the underlying metabolic changes may have been developing for years.
Knowing basic indicators such as blood pressure, blood glucose and cholesterol can therefore provide valuable information long before a medical emergency occurs.
The rise of metabolic risks is not a reason for panic.
It is a reason to treat prevention and routine health screening as part of ordinary healthcare.
Because when it comes to metabolic health, what a person cannot feel today can still shape their health years from now.
