Introduction to metabolism

Metabolism describes all chemical processes happening continuously inside the body to keep you alive and your organs functioning normally. This includes processes such as breathing, repairing cells and digesting food. These complex chemical processes require energy to perform, with the minimum amount required termed the Basal Metabolic Rate (BMR).

Myth: People who are obese have the same metabolism as people who are a normal weight

Fact: There are many potential differences in the metabolic system of people with obesity and normal weight individuals. A key difference is insulin resistance, when blood sugar levels in the body fail to respond normally to the production of insulin. Insulin resistance can lead to type 2 diabetes and heart disease, two common comorbidities associated with obesity.1,,,

Other metabolic differences may include leptin resistance, muscle efficiency and the body’s response to eating a meal.

Myth: If you exercise and eat right, metabolism doesn’t matter

Fact: Whilst exercising and eating right are important to maintain a healthy lifestyle, some individuals still struggle to lose weight based on lifestyle modification alone. A growing body of research supports the concept of ‘set point’, where it is thought that regardless of what you would like your weight to be, your brain has its own sense of how much body fat you should retain and regulates energy intake and expenditure to maintain levels within a ‘set point’ range.

Moreover, research suggests that when people with obesity go on a calorie-deficit diet then there are significant alterations in appetite hormones leading to increased food intake, reductions in energy expenditure including changes in ‘muscle efficiency’ that together can increase body weight.,

Myth: A ‘slow’ metabolism causes obesity

Fact:A number of studies involving thousands of people worldwide have failed to find evidence to support the widely held belief that overweight people must have slower metabolic rates.,,

Metabolism is complex and there are many factors that affect the amount of energy we use – including ‘resting’ energy requirements, exercise and the body’s response to food. Some studies suggest that overweight people may actually have a higher BMR than their leaner counterparts, reflecting the resting energy requirements needed to maintain a larger body size.,,,

Another factor is the thermogenic response to food – this is the added energy we need to process and store the food we eat. Research suggests that there are subpopulations that have a thermogenic defect when they eat, which can affect metabolism. Individuals with this defect are more prone to obesity.7 However, not all people with obesity have this defect, suggesting there are different causes for obesity.7

Myth: Prevention strategies are more effective than treatment

Fact: Researchers and doctors are increasingly aware that obesity is a disease with complex origins. It is now understood that environmental, social, and dietary factors and aspects relating to common medications, stress and sleep are thought to play a role, as such there is no ‘one size fits all’ approach to combatting obesity. In addition, prevention strategies are of little use to those already severely affected by obesity.

For those severely affected by obesity and associated diseases, it is vital that they are treated as patients and given access to viable treatment options such as professional lifestyle intervention, pharmacotherapy and surgery. In fact, bariatric surgery has shown significant results in treating type 2 diabetes in patients with obesity for whom medical plus lifestyle therapy is insufficient.

Myth: You can be obese and healthy

Fact: Although some people living with obesity maintain a healthy metabolic profile, recent research suggests that they have a greater risk of developing heart disease than normal-weight individuals. A major study of more than half a million people across Europe found those who were overweight or obese had up to a 28% higher risk of developing coronary heart disease – where arteries in the heart become clogged leading to heart attacks or heart failure. Another study found that so-called ‘healthy obese’ people have a 7% higher risk of stroke, twice the risk of heart failure, and a greater risk of peripheral artery disease (which is the narrowing of blood vessels to the arms and legs).

Myth: The stigma towards people who are obese has decreased in recent years.

Fact: Unfortunately, despite the science, the social stigma towards obesity still exists.21 The belief that obesity is a lifestyle choice remains prominent, significantly affecting the psychosocial wellbeing and behavioral patterns of people with obesity., Living with obesity has also been demonstrated to lead to significant personal and professional disadvantages, with obese people less likely to marry or reach their educational potential and, on average, earn less than normal weight individuals.23,24,

With this in mind, it’s time to redefine our attitudes towards obesity. It’s Time to Act.