Five common myths about obesity – and what we now understand

Many people living with weight challenges have heard the same messages for years. Modern research has helped us understand that obesity is far more complex than many of these older beliefs suggested. Obesity is a complex condition influenced by biology, genetics, environment and behaviour.

Effective treatment usually combines lifestyle changes, behavioural support, and, sometimes, medication and/or surgery.

Myth 1: ‘Weight is just about willpower’

For a long time, people were told that losing weight simply required eating less and moving more. While lifestyle choices are important, we now know that body weight is also influenced by genetics, hormones, brain signalling, sleep, stress and the obesogenic environment, in particular the modern food environment. Appetite regulation in the brain and metabolic adaptations can make weight loss and maintenance much harder than they appear on the outside. Recognising obesity as an inflammatory chronic medical condition helps move the conversation away from blame and towards effective support.

Myth 2: ‘If you lose weight quickly, you can always keep it off’

Many people have successfully lost weight in the short term through restrictive diets. However the body often responds to weight loss by increasing hunger hormones and lowering energy expenditure, making regain common. ‘Yo-yo dieting’ is the repeated cycle of losing weight through strict dieting and then regaining it again, often because the body adapts by slowing metabolism and increasing hunger, making long-term weight maintenance difficult. Sustainable weight management usually involves gradual lifestyle change, building supportive habits and protecting muscle mass through adequate protein intake and strength activity (resistance exercise).

Myth 3: ‘All calories are the same’

While energy balance matters, the type of food we eat can influence hunger, satiety (feeling full) and metabolic health. Metabolic health means your body is efficiently managing blood sugar, blood pressure, cholesterol, and energy balance to support overall health. Meals rich in protein, fibre and whole foods tend to keep people fuller for longer, whereas highly processed foods can be easy to overconsume and are likely to trigger reward pathways in the brain. The quality of food therefore plays an important role in appetite regulation and long-term weight management.

Our brains are wired to help us survive by encouraging behaviours that feel rewarding. When we do something enjoyable—such as eating, socialising or being active—the brain releases a chemical called dopamine, which creates a sense of pleasure and satisfaction. This system is often called the brain’s reward pathway.

Over time, the brain learns to link certain situations or cues with that feeling of reward. For example, seeing a favourite snack in the cupboard, smelling food cooking, feeling bored in the evening, or sitting down to watch television may all act as triggers. These triggers can lead to a craving, which then leads to eating, followed by the pleasurable feeling of reward. The brain remembers this pattern and becomes more likely to repeat it.

In today’s food environment, many foods are designed to be very appealing. Highly processed foods often combine sugar, fat, salt and flavourings in ways that strongly stimulate the brain’s reward system. This is one reason why people may feel it is difficult to stop eating these foods once they start—it is not simply about willpower, but about how the brain responds to these powerful signals.

Another helpful concept is that different foods affect the body in different ways once we eat them. For example, protein-rich foods such as eggs, yoghurt, beans, fish or chicken tend to keep us fuller for longer. This is partly because the body has to work a little harder to digest protein compared with carbohydrates or fats. In simple terms, digesting protein uses slightly more energy (calories) than digesting the other macronutrients. This does not mean protein is a magic solution, but it is one reason why meals that include good sources of protein often feel more satisfying and may help reduce snacking later.

The encouraging part is that the brain is adaptable. By changing our environment, building new routines and choosing balanced meals that include protein, fibre and whole foods, we can gradually create new patterns. Over time, the brain begins to associate reward with healthier habits instead. With small, repeated changes, the craving–reward cycle can slowly be ‘rewired’, making healthier choices feel more natural.

Myth 4: ‘Medication for weight is the easy way out’

For some individuals, medications can be a helpful medical tool when lifestyle changes alone have not been enough. Treatments such as Semaglutide (Wegovy) and Tirzepatide (Mounjaro) work by affecting appetite signals, satiety and blood sugar regulation. They have been shown to reduce the risk of major cardiovascular events such as heart attack and stroke in people with obesity and/or type 2 diabetes. They do not replace healthy habits, but can make it easier for people to implement them by reducing cravings and excessive hunger.

Myth 5: ‘Obesity is only about appearance’

In reality, obesity is closely linked with many health conditions, including type 2 diabetes, cardiovascular disease, fatty liver disease and joint problems. Even modest weight reduction—around 5–10% of body weight—can lead to meaningful improvements in blood pressure, blood sugar and overall health. The goal is therefore not cosmetic change but improved wellbeing, mobility and quality of life.

The key message is that obesity is a complex chronic condition influenced by biology, environment and behaviour. Effective treatment usually involves a combination of nutrition, physical activity, behavioural support, and, in some cases, medical therapies. Understanding the science helps to approach weight management with greater compassion, realism and hope.

For more advice from our weight loss expert Dr Ulrike Naumann, get in touch to arrange an appointment at our Weight Loss Clinic. Explore how medical expertise, lifestyle guidance, and – where appropriate – judicious use of medication can support your goals.