Fasting and the heart
One of the main reasons I decided to try fasting was that tests had suggested I was heading for serious problems with my cardiovascular system. Nothing has happened yet, but the warning signs were flashing amber. The tests showed that my blood levels of LDL (low-density lipoprotein, the “bad” cholesterol) were disturbingly high, as were the levels of my fasting glucose.
To measure “fasting glucose” you have to fast overnight, then give a sample of blood. The normal, desirable range is 3.9-5.8mmol/l. Mine was 7.3mmol/l. Not yet diabetic, but dangerously high. There are many reasons why you should do all you can to avoid becoming a diabetic, not least that it dramatically increases your risk of having a heart attack or stroke.
Fasting glucose is an important thing to measure because it is an indicator that all may not be well with your insulin levels.
When we eat food, particularly food rich in carbohydrates, our blood-glucose levels rise and the pancreas, an organ below the ribs and near the left kidney, starts to churn out insulin. Glucose is the main fuel that our cells use for energy, but the body does not like having high levels of it circulating in the blood. The job of insulin, a hormone, is to regulate blood glucose levels, ensuring that they are neither too high nor too low. It normally does this with great precision. The problem comes when the pancreas gets overloaded.
Insulin is a sugar controller; it aids the extraction of glucose from blood and then stores it in places like your liver or muscles in a stable form called glycogen, to be used when and if it is needed. What is less commonly known is that insulin is also a fat controller. It inhibits something called lipolysis, the release of stored body fat. At the same time, it forces fat cells to take up and store fat from your blood. Insulin makes you fat. High levels lead to increased fat storage, low levels to fat depletion.
The trouble with constantly eating lots of sugary, carbohydrate-rich foods and drinks, as we increasingly do, is that this requires the release of more and more insulin to deal with the glucose surge. Up to a point, your pancreas will cope by simply pumping out ever-larger quantities of insulin. This leads to greater fat deposition and also increases the risk of cancer. Naturally enough, this can’t go on forever. If you continue to produce ever-larger quantities of insulin, your cells will eventually rebel and become resistant to its effects.
Eventually the cells stop responding to insulin; your blood-glucose levels now stay permanently high and you will find you have joined the 285 million people around the world who have type 2 diabetes. It is a massive and rapidly growing problem worldwide.
Diabetes is associated with an increased risk of heart attack, stroke, impotence, going blind and losing your extremities due to poor circulation. It is also associated with brain shrinkage and dementia. Not a pretty picture.
One way to prevent the downward spiral into diabetes is to cut back on the carbohydrates and instead start eating more vegetables and fat, since these foods do not lead to such big spikes in blood glucose. Nor do they have such a dramatic effect on insulin levels. The other way is to try Intermittent Fasting.
Professor Mark Mattson, a professor of neuroscience at the National Institute on Aging in Baltimore is one of the most revered scientists in his field: the study of the ageing brain. I find his work genuinely inspiring – suggesting, as it does, that fasting can help combat diseases like Alzheimer’s, dementia and memory loss.
Mark points out that from an evolutionary perspective it makes sense. After all, the times when you need to be smart and on the ball are when there’s not a lot of food lying around. “If an animal is in an area where there are limited food resources, it’s important that they are able to remember where food is, remember where hazards are, predators and so on. We think that people in the past who were able to respond to hunger with increased cognitive ability had a survival advantage.”
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