Obesity Linked with 70% Higher Risk of Serious Diseases

Obesity is closely linked to a significantly higher risk of serious long-term diseases – including heart disease, Type 2 diabetes, and certain cancers. A major study published in The Lancet in early 2026 has now added to this picture, finding that people with obesity also face a 70% higher risk of hospitalisation or deaths specifically from infectious disease.

That statistic is striking, but it opens the door to a more useful conversation – one that focuses on understanding why weight gain happens, and what can be done about it in a sustainable, personalised way.

Understanding the factors that contribute towards obesity

Weight gain is often framed as a simple equation of calories in versus calories out. While energy balance does matter, this explanation rarely captures the full picture.

Hormones, metabolism, stress, sleep, and even the health of the gut, all play a role in how the body stores and uses energy. Two people can follow similar diets and exercise routines yet experience very different outcomes. That’s because underlying biology influences how the body responds.

Insulin resistance is one of the most important drivers. When the body becomes less responsive to insulin, it tends to store more fat, particularly around the abdomen. This same process also increases the risk of cardiovascular disease and Type 2 diabetes.

Chronic stress can contribute too. Elevated cortisol levels influence appetite, fat storage, and blood sugar regulation. Poor sleep disrupts hunger hormones, making it harder to regulate food intake. Over time, these factors combine, creating a metabolic environment that promotes weight gain.

Why obesity increases the risk of disease

Adipose tissue, or body fat, isn’t just passively stored. It acts as an active metabolic organ, releasing inflammatory signals and hormones that affect the entire body.

Excess body fat, particularly visceral fat around the organs, is associated with chronic low-grade inflammation. This inflammation plays a key role in the development of atherosclerosis, insulin resistance, and cellular dysfunction.

It also places strain on the cardiovascular system, increases blood pressure, and affects lipid metabolism. Over time, this creates the conditions for heart disease, stroke, and metabolic illness to develop.

The Lancet study found this systemic impact extends to infectious disease too. Researchers followed over 540,000 adults for an average of 13–14 years and found a clear, graded relationship: the higher the BMI, the greater the risk of serious infection. Importantly, this was an observational study and cannot establish causation directly, but the consistency of the finding across bacterial, viral, parasitic, and fungal infections suggests broad biological mechanisms are at work.

This helps explain why the risks associated with obesity go far beyond appearance or mobility. The impact is systemic.

A functional medicine perspective

As a consultant cardiologist and specialist in integrated and holistic health, certified by the Institute for Functional Medicine (IFM), Dr Konrad Grosser focuses on identifying the underlying drivers behind weight gain.

This means looking at factors such as insulin resistance, inflammation, hormone balance, thyroid function, gut health, and lifestyle patterns. It also means understanding how these factors interact, rather than viewing them separately.

A functional medicine approach to weight management is highly individual.

Some people may benefit from improving blood sugar control through balanced macronutrient intake. Others may need to address the health of the gut, reduce inflammation, or correct nutrient deficiencies. Sleep and stress management are also often just as important as dietary changes.

When metabolism becomes more balanced, weight loss tends to follow more naturally, without extreme or short-term measures.

Small changes, long-term impact

One of the most encouraging aspects of a more functional approach is that even modest improvements can have a meaningful effect on health. Improving insulin sensitivity, reducing inflammation, and supporting cardiovascular function can lower the risk of disease, even before significant weight loss occurs.

This shifts the focus from quick results to long-term health. It also makes change feel more achievable. With the right understanding and support, many of the underlying drivers can be addressed.

An integrative consultation with Dr Konrad Grosser offers a more in-depth look at the factors influencing weight and metabolic health, along with a personalised plan to reduce risk and improve long-term wellbeing. Book an appointment today.