We’re currently in the midst of the Muslim month of Ramadan. The holy month of fasting. All Muslims – of capable age and health – are expected to fast from sunrise to sunset. No water. No food. No sex. No dirty thoughts!
Why am I mentioning this? I’m not exactly the religious type.
I’ve always thought of fasting as something unpleasant, with no obvious long-term benefits. However, scientists have recently begun uncovering evidence that short periods of fasting, if properly controlled, could achieve a number of spectacular health benefits.
I watched a fascinating ’Horizon’ documentary on BBC television today. It’s available on BBC iPlayer on the internet if you can get access. The documentary was called ‘Eat, Fast and live longer’. The presenter ‘Michael Mosley’ was examining the science behind fasting. What he found was mind-expanding to say the least. You might not think it but fasting – or calorie restriction – can drastically improve your life-span, and help you to age gracefully. It can increase your life-span by decades, drastically reduce the probability of you dying from a heart attack or cancer, and make your brain cells grow so that you are at much lower risk of contracting Alzheimers and other brain diseases associated with old age.
Science is beginning to catch up – and this is what the latest cutting-edge science has to say:
The normal daily recommended calorific intake of 2,000 calories for men puts the body in ‘work’ and ‘growth’ mode. When the body is in ‘growth mode’ cells divide, DNA replicates and the body burns calories and lays down fat deposits. Effectively the body is in go-go mode. In gear five. This is all triggered by a chemical called IGF-1 (Insulin like growth factor). When you eat the normal recommended amount of calories the blood IGF-1 levels are high. It is the IGF-1 that puts the body into growth mode.
If you go into fasting mode, or if you drastically reduce your calorific intake, blood IGF-1 levels are drastically reduced and; this is the key thing, the body then goes into ‘repair mode‘. Faced with a reduction in calories, the body instead of diverting resources to grow cells, replicate and all other growth responses, it starts to repair itself. It’s almost like the body has a breather and goes into gear 1, and starts to repair DNA damage, repair cell membranes, repair internal structures and even repair brain cells. As levels of IGF-1 hormone drop, a number of repair genes appear to get switched on.
But it’s not simply about eating less. It’s about stimulating the body to go into repair mode, and the way you do that is to take a drastic reduction in calories for a couple of days. You can help by eating less protein and more plant matter. One current area of research is the 5:2 diet. That’s 5 days of eating normally followed by 2 days of a restricted calorie diet of about 600 calories per day (500 for a woman). If you do this diet for say 5 weeks you’ll lose weight, your IGF-1 levels will drop so your body will go into repair mode for considerably longer, your blood glucose and cholesterol levels will also drop – and you’ll feel great. If you can sustain this diet the risk of you suffering from diabetes, cancer, heart disease and much much more - drops dramatically.
Why should this be? Why should such a diet with days of plenty and than a couple of days of drastic calorie restriction, have such a massive impact on your health?
From an evolutionary point of view it makes perfect sense. Our ancestors only had access to food intermittently. They couldn’t just walk into a supermarket or a restaurant – their calorific intake depended on the vagaries of availability of food: good harvest, a succesfull hunt, good weather, or rain etc – so their bodies adapted to this by a simple rule of thumb: when food is plenty go into growth mode. When food is scarce go into repair mode. This worked perfectly for our ancestors. But it doesn’t work so well for us modern people because we rarely suffer periods of food scarcity. Our calorific intake remains high all the time and our bodies stay in growth and go-go mode. Our bodies rarely go into repair mode – so we suffer from all sorts of diseases and problems as a result.
Our bodies are adapted for a time when food was scarce and intermittent in supply. Our bodies are simply not adapted for the modern age of plenty. Because the modern age of plenty is a recent development and our bodies have not had time to adapt.
The path to good health is to trick the body into going into ‘repair mode’, and the way you do that, is to have intermittent days of reduced calorific intake.
The 5:2 diet. Try it. Five days of normal eating (1,800 calories women / 2,000 calories men), followed by two days of reduced calorific intake (500 / 600 calories per day)