The simple secret to a healthy life

WE ARE constantly bombarded with advice on a healthy lifestyle. We are led to believe that this is a complex area and that it is easy to make mistakes. But, for the average person, this is not true. Diet and exercise are two major building blocks of healthy lifestyle where best practice is well established and simple to follow.

Probably the single most helpful thing you can do for good health is to take regular moderate aerobic (exercising your lungs and heart) exercise. Jogging is the simplest way to get this exercise. The latest results from the Copenhagen City Heart Study were released at the EuroPRevent 2012 in Dublin in May. They show that regular jogging increases the life expectancy of men by 6.2 years and of women by 5.6 years. The optimum benefits come from one to 2.5 hours of jogging a week undertaken over two to three sessions, especially when performed at a slow or average pace. The ideal jogging pace makes you feel slightly breathless.

Jogging delivers multiple health benefits – it lowers blood pressure and improves heart function, improves bone density, boosts the immune system, prevents obesity, assists with sleep patterns and improves psychological functioning.

Running in company is much more enjoyable than running alone. You might think that running for three miles, three times a week is hard work, but it isn’t. Soon after starting a running session, your brain releases chemicals called endorphins. These are natural opiates that make you feel good. You quickly become addicted to the pleasure achieved from a combination of endorphins, the company of your companions and the general feeling of well-being associated with fitness.

Advice on what to eat for good health has grown into a Tower of Babel. Food is treated exclusively as a carrier of a huge number of nutritional elements. Much nutritional advice divides these elements into two long lists labelled “good” and “bad”. Thus for example, vitamins, omega fatty acids and fish are good and cholesterol, trans fats and red meat are bad. Items can suddenly disappear from a list, or move from one list to the other. Butter was once demonised and margarine was canonised, until it was discovered that margarine was far inferior to butter. Long lists of nutrient ingredients are printed on food packaging – these lists only make sense to a nutritionist.

For the average person who is not suffering from a medical condition, the formula for healthy eating is simple and easy: Eat a wide variety of whole foods in moderation, mostly plants. This advice is based on a huge amount of evidence, summarised, for example, by Michael Pollan in his book In Defence of Food (Penguin Press, 2008). Eating a wide variety of whole foods means that you cannot miss out on any important nutrient or trace element. Eating mainly whole food minimises the intake of processed food and eating in moderation means that you won’t grow fat. Humans are biologically adapted to thrive better on a diet rich in plant food, but no food is demonised by this advice.

Most nutritional studies look for correlations between ingestion of particular foods with particular positive or negative outcomes. The human body is very complex, making the results of these studies difficult to interpret correctly. One common error is to confuse correlation with causation. A recent Irish study showed that breast-fed babies are less likely to develop obesity later on in childhood than bottle-fed babies. It was concluded that breast milk conditions the metabolic development of children in a healthier manner than bottle-milk formula.

However, it seems to me that the situation is not that simple. Breast-feeding, on average, takes extra effort and breast-feeding mothers are determined to give their babies every advantage. A mother with such determination is unlikely to sit idly by later and watch her child eat its way into obesity, even if the baby was not breast-fed. The better outcome, obesity-wise, for the breast-fed baby is likely to be a combination of two factors – breast milk plus maternal mindset, not just breast milk alone.

So take plenty of aerobic exercise, eat whole foods in moderation, mostly plants, and choose your mother wisely. And try to be happy – life is short.

William Reville is an emeritus professor of biochemistry and public awareness of science officer at UCC understandingscience.ucc.ie