Obesity

The World Health Organization (WHO) estimated that in 2016, more than 1.9 billion adults (18 years and older) were overweight, and over 650 million of these were obese. Furthermore, more than 340 million children and adolescents aged 5-19 were overweight or obese. Obesity is defined as an abnormal accumulation of body fat in proportion to body size. It is linked to higher morbidity, premature mortality, chronic diseases, depression and cancer.

Factors Contributing to Obesity

The rise in obesity is attributed to a complex interplay of factors, including changes in dietary patterns, reduced physical activity, urbanization, sedentary lifestyles, and socio-economic factors. Genetic predisposition plays a role in an individual’s susceptibility to obesity, affecting metabolism, appetite regulation, and fat storage. However, genetics interact with other factors, and obesity is not solely determined by genes. Poor dietary habits, such as consuming high-calorie, low-nutrient foods and sugary beverages, contribute to weight gain. Sedentary lifestyles and reduced physical activity levels in today’s technology-driven world lead to an energy imbalance, where calorie intake exceeds expenditure. Environmental factors, like easy access to unhealthy foods and environments discouraging physical activity, also play a role. Socioeconomic status influences access to healthy options and education, and psychological factors such as stress and emotional eating can contribute to overeating. Sleep deprivation disrupts hunger-regulating hormones, further contributing to weight gain. Medical conditions, hormonal imbalances, cultural influences, and childhood factors all contribute to the complexity of obesity.

Plasma Leptin Levels

Lower plasma leptin levels can be associated with obesity, and this relationship is tied to the role of leptin in regulating appetite and body weight. Leptin is a hormone primarily produced by fat cells (adipocytes) in the body. Its primary function is to signal the brain, specifically the hypothalamus, about the body’s energy stores and overall fat mass. When fat stores increase, more leptin is released into the bloodstream. Leptin then travels to the brain, where it helps regulate appetite and energy expenditure. The main actions of leptin include:

• 1. Appetite Suppression: Leptin acts on the brain to reduce appetite and promote a feeling of fullness after eating. It signals to the brain that energy stores are sufficient, which helps regulate food intake and prevent overeating.
• 2. Energy Expenditure Regulation: Leptin helps regulate energy expenditure by influencing the body’s metabolism. It can increase energy expenditure by promoting physical activity and influencing metabolic processes.

In cases of obesity, there can be a disruption in the normal signaling of leptin. This disruption is often referred to as “leptin resistance.” Leptin resistance occurs when the brain becomes less responsive to the appetite-suppressing effects of leptin. As a result:

• 1. Higher Fat Mass: Despite higher levels of leptin in the bloodstream due to increased fat mass, the brain does not receive the expected signal of sufficient energy stores. This can lead to an inappropriate perception of hunger and reduced appetite suppression, potentially contributing to overeating and weight gain.
• 2. Impaired Energy Regulation: Leptin resistance can also affect energy expenditure, leading to reduced energy burned and lower overall metabolic rate. This can further contribute to weight gain and obesity.
• 3. Inflammation: Obesity-related inflammation and other factors can contribute to leptin resistance. Inflammatory molecules interfere with the normal signaling pathways of leptin, reducing its effectiveness in regulating appetite and energy expenditure.

It’s important to note that while lower plasma leptin levels are not the direct cause of obesity, they can be a reflection of leptin resistance and disrupted appetite regulation that are often seen in individuals with obesity. The relationship between leptin, appetite, and obesity is complex and involves multiple physiological and hormonal factors. Research into understanding and addressing leptin resistance is ongoing and is an important aspect of tackling obesity and its associated health risks.

Obesity Phenotypes

The term “obesity phenotype” refers to the observable characteristics or traits associated with obesity in an individual. The pattern of body fat distribution is recognised as an important predictor of the health risks associated with obesity. Not all cases of obesity are the same, and different individuals may exhibit variations in terms of how obesity presents itself and its associated health risks. These variations are often referred to as different obesity phenotypes.

Some common obesity phenotypes include:

• 1. Android (Central) Obesity: This phenotype is characterized by excess fat accumulation in the abdominal area, giving rise to an “apple-shaped” body. Individuals with android obesity are at a higher risk for cardiovascular diseases, diabetes, and metabolic syndrome due to the proximity of visceral fat to vital organs.
• 2. Gynoid (Peripheral) Obesity: Gynoid obesity is characterized by excess fat accumulation in the hips, thighs, and buttocks, resulting in a “pear-shaped” body. This phenotype is associated with a lower risk of certain health issues compared to android obesity.
• 3. Metabolically Healthy Obesity (MHO): Some individuals with obesity do not exhibit the typical metabolic disturbances often associated with obesity, such as insulin resistance, high blood pressure, and abnormal blood lipid levels. They are considered metabolically healthy obese individuals and may have a lower risk of certain obesity-related complications.
• 4. Metabolically Unhealthy Obesity (MUO: This phenotype is characterized by the presence of metabolic disturbances commonly associated with obesity, such as insulin resistance, high blood pressure, and dyslipidemia. Individuals with MUO are at a higher risk of developing cardiovascular diseases and other obesity-related health problems.
• 5. Childhood-Onset Obesity: Some individuals develop obesity early in life, during childhood or adolescence. Childhood-onset obesity may have different genetic and environmental factors contributing to its development compared to adult-onset obesity.
• 6. Adult-Onset Obesity: This phenotype refers to individuals who develop obesity later in life, often due to changes in lifestyle, dietary habits, and physical activity levels.

It’s important to note that these phenotypes are not always distinct categories, and individuals can exhibit a combination of characteristics. Additionally, research into obesity is ongoing, and our understanding of the various phenotypes and their underlying causes continues to evolve. The identification and study of different obesity phenotypes can help tailor interventions and treatments to address the specific needs and health risks of individuals with obesity.

Health impacts of Obesity

Obesity has significant health implications and is associated with a wide range of negative health outcomes. It increases the risk of various chronic diseases and can have a substantial impact on both physical and mental well-being. Here are some of the health implications of obesity:

1. Cardiovascular Diseases: Obesity is a major risk factor for heart diseases such as coronary artery disease, heart failure, and stroke. Excess body fat can lead to elevated blood pressure, atherosclerosis (narrowing of arteries), and other cardiovascular complications.
2. Type 2 Diabetes: Obesity is closely linked to insulin resistance, which is a key factor in the development of type 2 diabetes. The excessive fat tissue can disrupt insulin signaling, leading to high blood sugar levels and diabetes.
3. Metabolic Syndrome: Obesity is a central component of metabolic syndrome, a cluster of conditions including high blood pressure, high blood sugar, abnormal cholesterol levels, and abdominal obesity. Metabolic syndrome increases the risk of heart disease, stroke, and diabetes.
4. Certain Cancers: Obesity is associated with an increased risk of several types of cancer, including breast, colon, endometrial, kidney, and pancreatic cancers.
5. Respiratory Issues: Obesity can lead to impaired lung function and increased risk of conditions such as sleep apnea, asthma, and obesity hypoventilation syndrome.
6. Musculoskeletal Disorders: Excess weight places extra stress on joints and bones, increasing the risk of conditions like osteoarthritis and back pain.
7. Fatty Liver Disease: Non-alcoholic fatty liver disease (NAFLD) is common in individuals with obesity and can progress to more severe forms, such as non-alcoholic steatohepatitis (NASH) and cirrhosis.
8. Gastrointestinal Issues: Obesity increases the risk of gastroesophageal reflux disease (GERD), gallstones, and other digestive disorders.
9. Reproductive and Hormonal Issues: Obesity can lead to hormonal imbalances, menstrual irregularities, fertility problems, and complications during pregnancy.
10. Psychological and Mental Health Impact: Obesity can contribute to poor body image, low self-esteem, depression, anxiety, and social isolation.
11. Reduced Life Expectancy: Obesity is associated with a shorter life expectancy due to its impact on chronic disease risk and overall health.
12. Economic Burden: Obesity places a significant economic burden on healthcare systems due to increased medical costs related to obesity-related conditions and treatments.
13. Quality of Life: Obesity can reduce quality of life by limiting physical activities, affecting mobility, and causing discomfort or pain.

Preventing and managing obesity is crucial for reducing these health risks. Lifestyle changes, including adopting a balanced and nutritious diet, engaging in regular physical activity, getting enough sleep, managing stress, and seeking medical guidance, can help address and mitigate the health implications of obesity. It’s important to approach obesity as a complex condition that requires a comprehensive and multidisciplinary approach to promote better health outcomes.

Obesity Management

The management of obesity for global health needs to be multifaceted and involve many levels of interventions.

Population Level Obesity Interventions

Population-level obesity interventions focus on implementing strategies that address obesity on a larger scale, targeting entire communities or populations. These interventions aim to create environments that promote healthy behaviours and prevent weight gain. For instance, some countries have introduced taxes on sugary beverages like soda and energy drinks, discouraging their consumption and ultimately reducing calorie intake. Another approach involves implementing clear and easily understandable nutrition labels on the front of food packaging, enabling consumers to make informed and healthier food choices. In schools, policies that improve the nutritional quality of meals and limit the availability of unhealthy snacks can help establish healthier eating habits among children. Additionally, urban planning initiatives that prioritize walkable neighbourhoods, bike paths, and access to parks encourage physical activity and reduce reliance on cars, contributing to a more active lifestyle. By restricting the marketing and advertising of unhealthy foods, especially to children, and offering community-based programs that provide nutrition education, cooking classes, and support groups, individuals can be empowered to adopt healthier lifestyles. Workplace wellness programs, public health campaigns, and initiatives to improve access to nutritious foods in underserved areas are all part of the comprehensive approach to tackling obesity at the population level.

Individual Level Obesity Interventions

Individual-level obesity interventions are designed to target and assist individuals in making healthier choices and adopting behaviours that promote weight management and overall well-being. The key is personalised care, recognising that each individual’s path to weight management is distinct. By offering tailored guidance, education, and support, individuals can acquire the tools and motivation needed to establish sustainable lifestyle changes and achieve their weight and health objectives.

Interventions aim to encourage healthier eating patterns, increased physical activity, and other lifestyle changes on an individual basis. One approach used regularly be exercise physiologists involves behavioural counselling and involves working closely with individuals to establish personalised goals, develop healthy eating plans, and create sustainable strategies for effective weight management. This includes prescription of tailored physical activity plans based on an individual’s fitness level, preferences, and health objectives. By providing nutritional education, individuals can gain a better understanding of portion control, balanced eating, and the importance of nutrient-rich foods. Additionally, teaching mindful eating practices helps individuals develop awareness of hunger and fullness cues, facilitating more conscious food choices and reducing overeating, guidance in meal planning and preparation equips individuals with the skills to create wholesome meals at home, reducing reliance on processed foods and fast food options.

Stress management techniques, such as meditation, deep breathing, and yoga, are taught to help individuals cope with emotional triggers for overeating. In certain cases, medication or medical interventions may be considered under the supervision of healthcare providers. For individuals with severe obesity and related health concerns, surgical options like gastric bypass or sleeve gastrectomy might be recommended following thorough evaluation and counselling.

To learn more about how to prescribe and implement these interventions continue reading this article.