Fasting For A Long, Healthy Life

Fasting is commonly practiced by people for religious or spiritual reasons and by those who are desperate to lose weight. But it has been alleged that fasting is a bad way to lose weight because we lose the stimulatory effect of eating, which encourages our metabolism to burn more calories, when we go without food. 

It’s alleged that when we fast our bodies think we are facing starvation and shut down our metabolism, preventing or at least slowing down the weight loss we are aiming to achieve. 

 

This is why we are often told that we should not skip breakfast if we are trying to lose weight – it is, after all the meal that ‘breaks’ the ‘fast’ of sleep. In addition, it is said that we should eat regular, small meals to keep our metabolic fire stoked up, burning up those calories, because eating itself burns calories. 

But research is increasingly coming out, which seems to show the opposite – that fasting can be an ideal way to lose weight.

The bad news is that restricting calorie consumption is the only method that’s been proven to extend  a life – at least in animals.  For some years now there has been a small group of people called CHRONies (Calorie Restricters on Optimal Nutrition) who seem also to bear witness to this. They are a group of biologically very fit (low cholesterol and low blood sugar), very lean people who achieve this goal by severely restricting the number of calories they eat every day. They also obtain those calories from the most nutritious sources. They look incredibly fit and young for their years – so why is this group very small? Probably because few of us have the willpower to sustain such long-term self-discipline, and most of us enjoy food way too much, for cultural as well as culinary reasons.

But the good news is that there is evidence that fasting for no more than two days a week may lead not only to weight loss but improvements in other measures of health such as cholesterol and fasting blood sugar levels, body mass index, and other metrics, as well. 

And for once, it’s not too good to be true…

Intermittent fasting

Known also as the Fast Diet or the ‘5:2 plan’ devised by British physician, Dr.Michael Mosley, intermittent fasting is causing a stir in nutritional, antiaging and weight-loss circles.  Intermittent fasting involves severely restricting calorie intake on ‘fast’ days to a quarter of a person's normal intake i.e. about 500 calories a day for women and 600 for men.  These calories should be spread out – ideally with at least 12 hours between – to give that all-important fasting period.

Why Is Fasting Beneficial?

 

Our bodies have not evolved since the days when food was not always to hand as it is for most of us in the Western world today. In prehistoric times, one day we might have a hairy mammoth to feast on, but the next and the next after that there might be nothing. 

Furthering our species is dependent on growth and reproduction, which require food for energy.  So when food is plentiful our bodies produce lots of a hormone called Insulin-like Growth Factor (IGF-1) that encourages growth and energy output. 

But the relentless and continuous production of IGF-1 has been likened by Prof Valter Longo, of the University of Southern California’s Longevity Institute, to driving a car continuously with your foot flat to the floor and never having it serviced. In other words it’s soon going to break down. 

But when fasting, the body realizes that growth is not a good idea and reduces production of IGF-1.  Prof. Longo explains that not only does this take the foot off the accelerator, but it also allows the ‘mechanics’ (in this case your immune system and other factors at work in your body) in to do some repair and maintenance.  Although important when we are young and growing, as we age high levels of IGF-1 are linked to diseases including cancer and diabetes which are shortening modern lives.  Prof. Longo studied special mice, which were resistant to the effects of IGF-1.  As well as being smaller than other mice, they live twice as long, especially when they are fed calorie-restricted diets.  (That would be like humans living to nearly 170 years old!).  As long ago as 1945 it was found that intermittent fasting increased the life-span of rats.  It is only more recently that we have gained a better understanding of why this might be.

These start maintenance processes during which old, worn out cells are removed and replaced.  This is thought to be protective against aging and developing certain cancers. While the body is motoring along under the influence of lots of IGF-1, it is thought that there is no time for this essential disease-preventing maintenance.

Is it calorie restriction or fasting that produces benefits?

Both, actually, and here is why. Calorie restriction switches the body out of growth mode and reduces the levels of IGF-1 that are produced, but fasting seems to have specific benefits too. Two groups of rats were fed the same high-fat diet, with the same number of calories. One group could nibble away all day on the food, while the other group only had 8 hours to eat it, fasting for the rest of the time. Although both groups ate the same number of calories, the group on intermittent fasting put on 28% less fat and avoided the high cholesterol and liver damage suffered by the other group.

Follow the story…

The benefits of long-term fasting in terms of weight loss, and prevention of diabetes and cancer will each be the subject of separate articles on this site.  

So be sure to keep your eyes open for more information here on what intermittent fasting can do for you, whether you are trying to lose weight or you simply want to prioritize your health.