Over the years, a wide range of diets have been proposed, some of which have worked better than others. And how many of these have produced long term benefits? It could even be argued that some, like the low-fat diet, have even contributed further to chronic disease and obesity because it encouraged us to load up on starchy carbohydrate foods such as bread, potatoes and pasta instead.
In this article, we look at how important it is to focus on when to eat rather than on just what to eat and this is a process known as caloric restriction or intermittent fasting.
Through the science of evolutionary biology, we learn that our genes have changed very little since palaeolithic times, between 10,000 and 50,000 BC. But the changes to our lifestyles, particularly over the last 50 years, are unprecedented. It is these changes, and especially the over-abundance of simple carbohydrate foods such as bread, pasta, biscuits and cake, coupled with moving less, that cause changes in our genetic makeup that lead to the 35 or so chronic diseases that plague our society today.
Our Palaeolithic ancestors were able to undertake tremendous physical exertion without being able to fuel themselves on food first. How did they do this? The answer is that they were able to burn fat more easily than modern humans, which provided huge amounts of energy for them.
Physiologically, being able to burn fat makes us more metabolically flexible. This means that our body is able to produce energy according to our need. If we are over-reliant on carbohydrates, we become less adaptable to use our fat storage as fuel, and the body will rather switch to carb-burning instead of fat-burning if carbs are provided. So, being over-reliant on carbohydrates prevents us from being metabolically flexible and our vitality is greatly reduced.
A healthy energy-efficient body switches easily from using carbohydrates as an energy source, to burning fat, which is our evolutionary survival mechanism. This allowed us to survive periods when food was scarce while foraging and hunting for food. These periods were typically interspersed with cycles of rest and feasting.
Nowadays we can employ that same ‘feast-famine’ rhythm to encourage our body to be more metabolically flexible and burn fat by adopting calorie restriction or intermittent fasting. This can be easily done by eating two or three meals per day and cutting out the snacks.
When possible, do your workout in the morning after an overnight fast of minimum of twelve hours.