VINCENT MARKS LECTURE
ARTICLE
A tsunami of obesity: time for a national crusade?
If left unchecked, the current trend towards increasing obesity will have profound effects on the next generation and its health services, as Michael Ryan and Cheryl Flanagan explain.
The UK is experiencing a massive increase in the prevalence of obesity and is one of the worst affected countries of the developed world. The impact of obesity on general health and life expectancy should be a major cause for concern among all healthcare professionals. The personal and cultural sensitivities surrounding obesity have seriously limited open discussion of the topic as a health issue, but the impact of obesity on the nation’s health, and the future prospects for adverse impact on the life expectancy of the next generation, demand a clear understanding of the true nature of obesity as a health concern rather than a ‘cosmetic’ issue.
CAUSES OF OBESITY The World Health Organization (WHO) defines obesity as a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Clinically, obesity is defined as having a body mass index (BMI, Wt[kg]/Ht[m]2
) greater than 30 kg/m2
This represents an excess storage of approximately 100,000 calories as body fat. This degree of excess calories is the
result of a chronic imbalance between intake and expenditure. The First Law of Thermodynamics states that energy cannot be created nor destroyed, but merely moves from one form to another, and it applies to human nutrient balance as well as physics and chemistry. A fundamental issue in relation to clinical obesity is the nature of the relationship with food in our society. The prevalence of obesity in our society is a product of many complex and interacting factors that determine the role of food in our lives. The net fat content of the patient is the result of metabolic, genetic, emotional, cultural and
DECEMBER 2013 .
social factors that have affected their life up to the point of presentation to the health service. True ‘genetic obesity’ is very rare and accounts for a small percentage of obese patients. Genetic factors probably contribute in various degrees to a much higher proportion of obese individuals, up to 20%, but no specific mutation that can influence treatment or mitigate the impact of obesity on health has been identified. The genetic makeup of the population at large has not altered in the past 40 years; it is the rise in availability and accessibility of delicious, calorie-dense foods, coupled with the decline in physical activity, that has led to
the inexorable rise in the prevalence and severity of obesity in the general population. Obesogenic environmental factors
include a relative lack of recreational areas, convenience foods that are high in calories, and increased sedentary occupational and leisure time compared to previous generations.
SCALE OF THE PROBLEM Obesity risk tracks through the generations, and the risk of obesity among teenagers is approximately 30% for those with one obese parent and almost 50% for both boys and girls who have two obese parents. Another significant issue in terms of health and life expectancy is the duration of obesity. Each decade of obesity approximately doubles the risk of death, cardiovascular disease and cancer mortality. Being obese for more than 25 years triples the above risk. A major concern for the younger generation is that the onset of obesity is 10 years earlier than that seen in the ‘current’ generation of adults.
How L S Lowry might have portrayed figures had he been painting in the 21st century. THE BIOMEDICAL SCIENTIST 699
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