The recent rise in the prevalence of obesity is now a major medical, social and political issue. It is a problem facing most western societies. Twenty per cent of adults are obese with BMI>30. In the US it is calculated that adults put on 0.8Kg per year. The picture in Ireland is similar. When the IMJ raised this matter a few years ago we called for the establishment of a taskforce. The Minister has now set up such a body.
The next question is how the group will tackle the problem.
One of the difficulties is that society is only now waking up to a concern that has been a long time in the making. The 1970s saw the arrival of soft drinks, the emergence of convenience foods and a decline in home cooking. These adverse dietary changes have been compounded by a reduction in daily physical activities. Exercise has decreased at work, school and at home. The modern environment is anti-activity. Individuals with a low energy pattern are set up for obesity.
The science of weight control is showing that it is difficult to maintain an optimal weight when physical activity is low. There are many studies depicting sedentary lives. A recent Scottish schoolchildren study revealed that 76% of monitored hours were spent in low activity. Only 20
minutes of their day was spent in anything approaching vigorous activity.
This is suboptimal in that children need at least 1 hour in brisk play. Contrary to previous perceptions, children do not spontaneously go about burning up energy. Like adults they appear to need opportunity and encouragement. The 21st century promotes inactivity and children are not immune.
Recent research suggests that the problem is not as insurmountable as previously thought. Small increases in physical activity and small reductions in calorie intake can reap large dividends. There is only 100-200 Kcal daily difference between weight gain and weight control. Walking 2000 additional steps is sufficient to expend the 100Kcals that cause the problem.
Exercise has many benefits. Free fatty acids are utilised during exercise. Increased levels of adrenaline acting through cAMP stimulate hormone sensitive lipase. This enzyme converts triglycerides to fatty acids which are bound to albumin for delivery to exercising muscle. Trained muscle can accommodate a greater maximum blood flow because of the growth of new capillaries.
Fit individuals have a 60% greater number of capillaries than their sedentary counterparts. The blood lingers longer in the muscle with a greater oxygen extraction.
There are examples that society can change its attitude to diet and exercise in a short space of time. In 1972 Finland had the world’s highest mortality from heart disease. Their diet, not dissimilar to our own, consisted of red meat, potatoes, butter, milk and salt. A massive targeted public health campaign was launched to encourage a daily evening walk and the serving of salads and vegetables.
A free school lunch with a hot dish and a salad was provided. An element of competition was introduced in that the population were exhorted to become healthier than their neighbouring countries. Over 25 years the cardiac mortality fell by 75%.
One of the indicators of the obesity problem is the rise in type 2 diabetes, a condition previously encountered in the over 40s. In the mid 1990s the incidence of type 2 diabetes in the under 40s doubled, almost always occurring in obese individuals.
To be effective a public directive must be achievable, popular and widely acceptable. The message must be simple. ‘A
few more steps, a few less bites’.