When I began writing for The Observer four years ago, I was of the opinion that a fair amount of dietary dogma was lacking in substance. More than that, my belief was that by eating what is traditionally billed as a 'healthy' diet we could well be digging a hole for ourselves with our knives, forks and spoons. Over the years, one of my aims has been to expose sometimes deep-set concepts that, by my reckoning, have been fuelled less by concern for public health and more by the food industry's desire for profit. My final column here seems like an appropriate opportunity to review whether, over the past years, we have shown any signs of an increased appetite for new nutritional thinking.
The party line on healthy eating has been a diet low in fat and rich in carbohydrate. In particular, we are encouraged to base our diet around 'complex carbohydrates' such as bread, potatoes, rice, pasta and breakfast cereals. These have are recommended on the basis of their largely fat-free nature, as well as their assumed ability to give a slow and sustained release of sugar.
However, many of the starchy staples we have been encouraged to have our fill of actually release their sugar quite rapidly into the bloodstream. It is known that these high-glycaemic index (GI) foods, will tend to stimulate the secretion of copious quantities of the sugarlowering hormone insulin. While insulin is essential to life, excesses of it are believed to promote an array of undesirable health issues including obesity, diabetes and heart disease.
Not only do high-GI foods cause critical, health-eroding imbalances in the body's biochemistry, but they have also been found to have less appetite-sating effects compared to lower-GI fare. And that's not all: other than the carbohydrate they contain, many starchy foods, such as white rice, pasta and potato contain precious little else from a nutritional perspective. In the past four years I have personally been pleased to witness growing and lasting awareness that by swallowing conventional nutritional advice we run the risk of ending up overfed, but malnourished.
What I believe to be a mini-revolution in nutrition seems to have been sparked by the sudden explosion of interest in the Atkins diet. While this diet is too extreme and one-dimensional in its focus for my liking, it did at least serve to highlight the potential hazards associated with consuming a diet rich in certain carbs. I am delighted to see that more recently, the GI has been popularised through dietary regimes that are more balanced and wholesome in their approach.
Such diets have highlighted the fact that many foods, including fruits, non-starchy vegetables, beans, nuts and seeds have relatively low GIs, and at the same time offer considerable stashes of health-giving nutrients. Other foods that tend to stabilise blood sugar and insulin include intrinsically low-carb foods such as meat and eggs. However, the GI of a food is not the sole arbiter of whether a food is healthy or not, and animal foods such as these are generally viewed in a dim light on the basis of their high content of supposedly disease-making substances, such as saturated fat and cholesterol.
Yet studies have found that cutting back on fat is, for the most part, spectacularly unsuccessful in terms of bringing about weight loss or protecting us from conditions such as heart attack and stroke. The fact that reducing saturated fat and cholesterol intake seems to offer little in the way of health benefit strongly suggests that these dietary elements are not the spectres they are so often made out to be.
These and other factors can make it difficult to sort the wheat from the chaff when attempting to interpret the science accurately. For those seeking a simpler way to discern the facts about food, I suggest going back to basics. An abiding principle I would like to leave you with is that we can make quick and generally accurate decisions about the best kind of diet by contemplating what our ancient ancestors ate. It makes sense that the foods that have been in the human diet for the longest during our evolutionary process are the ones we are best adapted to genetically, physiologically and biochemically, and are therefore the ones most likely to maintain our health and well-being.
It is perhaps easy to visualise our hunter-gather relatives chowing down on fruit and veg and nuts and seeds, as well as occasional meat, fish and eggs. On the other hand, there's something not quite right about an image of early men and women sitting around camp fires tucking into plates of pasta, bowlfuls of processed breakfast cereals and stacks of bread.
In my very first offering for The Observer, I made the point that a healthy diet is one that is ostensibly made from unprocessed foods found naturally in nature. All the credible scientific research I have come across in the last four years has only served to make me even more confident of this basic notion. My belief is that while what it means to eat a truly healthy diet can be found by close scrutiny of the science, I also reckon this can be more simply discerned by using nothing more than common sense.