The Fast Diet: The secret of intermittent fasting � lose weight, stay healthy, live longer (5 page)

One of the things that Professor Valter Longo and others told me before I began my four-day fast was that it would be tough initially, but that after a while I would start to feel more cheerful, which was indeed what happened. Similarly, I was surprised to discover how positive I have felt while doing Intermittent Fasting. I expected to feel tired and crabby on my fasting days, but not at all. So is this simply a psychological effect, that people who do Intermittent Fasting and lose weight feel good about themselves, or are there also chemical changes that are influencing mood?

According to Professor Mark Mattson, one of the reasons people may find Intermittent Fasting relatively easy to do due to its effects on BDNF. BDNF not only seems to protect the brain against the ravages of dementia
and age-related mental decline, but it may also improve your mood.

There have been a number of studies going back many years that suggest rising levels of BDNF have an antidepressant effect, at least in rodents. In one study, they injected BDNF directly into the brains of rats and found this had similar effects to repeated use of a standard antidepressant.
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Another paper found that electric shock therapy, which is known to be effective in severe depression, seems to work, at least in part, because it stimulates the production of higher levels of BDNF.
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Mark Mattson believes that within a few weeks of starting a two-day-a-week fasting regime, BDNF levels will start to rise, suppressing anxiety and elevating mood. He doesn’t currently have the human data to fully support this claim, but he is doing trials on volunteers which involve, among other things, collecting regular samples of cerebrospinal fluid (the liquid that bathes the brain) in order to measure the changes that occur during intermittent fasts. This is not a trial for the faint-hearted as it requires regular spinal taps, but as Mark pointed out to me, many of his volunteers are already undergoing early signs of cognitive change, so they are extremely motivated.

Mark is keen to study and promote the benefits of Intermittent Fasting as he is genuinely worried about the likely effects of the current obesity epidemic on our brains
and our society. He also thinks if that if you are considering Intermittent Fasting you should get going sooner rather than later: ‘The age-related cognitive decline in Alzheimer’s disease, the events that are occurring in the brain at the level of the nerve cells and the molecules in the nerve cells, those changes are occurring very early, probably decades before the subject starts to have learning and memory problems. That’s why it’s critical to start dietary regimes early on, when people are young or middle-aged, so that they can slow down the development of these processes in the brain and live to be 90 with their brain functioning perfectly well.’

Like Mark, I’m convinced the human brain benefits from short periods abstaining from food. This is an exciting and fast-emerging area of research that many will watch with great interest. Beyond the brain, though, Intermittent Fasting also has measurable, beneficial effects on other areas of the body – on your heart, on your blood profile, on your risk of cancer. And that’s where we’ll turn now.

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 the fact 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. It’s rather like shouting at your children; you can keep escalating things, but after a certain point they will simply stop listening.

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. Over the last 20 years, numbers have risen almost tenfold and there is no obvious sign that this trend is slowing.

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.

In a study from 2005, eight healthy young men were asked to fast every other day, 20 hours a day, for two weeks.
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On their fasting days they were allowed to eat until 10pm, then not eat again until 6pm the following evening. They were also asked to eat heartily the rest of the time to make sure they did not lose any weight.

The idea behind the experiment was to test the so-called ‘thrifty hypothesis’, the idea that since we evolved at a time of feast and famine the best way to eat is to mimic those times. At the end of the two weeks, there were no changes in the volunteers’ weight or body-fat composition, which is what the researchers had intended. There was, however, a big change in their insulin sensitivity. In other words,
after just two weeks of Intermittent Fasting, the same amount of circulating insulin now had a much greater effect on the volunteers’ ability to store glucose or break down fat.

The researchers wrote jubilantly that, ‘by subjecting healthy men to cycles of feast and famine we changed their metabolic status for the better’. They also added that, ‘to our knowledge this is the first study in humans in which an increased insulin action on whole body glucose uptake and adipose tissue lipolysis has been obtained by means of Intermittent Fasting.’

I don’t know what impact Intermittent Fasting has had on my insulin sensitivity – it’s a test that is hard to do and extremely expensive – but what I do know is that the effects on my blood sugar have been spectacular. Before I started fasting, my blood glucose level was 7.3 mmol/l, well above the acceptable range of 3.9 – 5.8 mmol/l. The last time I had my level measured it was 5.0 mmol/l, still a bit high but well within the normal range.

This is an incredibly impressive response. My doctor, who was preparing to put me on medication, was astonished at such a dramatic turnaround. Doctors routinely recommend a healthy diet to patients with high blood glucose, but it usually only makes a marginal difference. Intermittent Fasting could have a
revolutionary
, game-changing effect on the nation’s health.

My father was a lovely man but not a particularly healthy one. Overweight for much of his life, by the time he reached his 60s he had developed not only diabetes but also prostate cancer. He had an operation to remove the cancer that left him with embarrassing urinary problems. Understandably, I am not at all keen to go down that road.

My four-day fast, under Professor Valter Longo’s supervision, had shown me that it was possible to dramatically cut my IGF-1 (Insulin-like Growth Factor 1) levels and by doing so, hopefully, my prostate cancer risk. I later discovered that Intermittent Fasting had a similar effect on my IGF-1 levels. The link between growth, fasting and cancer is worth unpacking.

The cells in our bodies are constantly multiplying, replacing dead, worn-out or damaged tissue. This is fine as long as cellular growth is under control, but sometimes a cell mutates, grows uncontrollably and turns into a cancer. Very high levels in the blood of a cellular stimulant, like IGF-1, are likely to increase the chance of this happening.

When a cancer goes rogue, the normal options are surgery, chemotherapy or radiotherapy. Surgery is used to try to remove the tumour; chemotherapy and radiotherapy are there to try and poison it. The major problem with
chemotherapy and radiotherapy is that they are not selective; as well as killing tumour cells they will kill or damage surrounding healthy cells. They are particularly likely to damage rapidly dividing cells such as hair roots, which is why hair commonly falls out following therapy.

As I mentioned above, Valter Longo has shown that when we are deprived of food for even quite short periods of time, our body responds by slowing things down, going into repair and survival mode until food is once more abundant. That is true of normal cells. But cancer cells follow their own rules. They are, almost by definition, not under control and will go on selfishly proliferating whatever the circumstances. This ‘selfishness’ creates an opportunity. If you fast just before chemotherapy, at least in theory, you create a situation where your normal cells are hibernating while the cancer cells are running amok and therefore more vulnerable.

In a paper published in 2008, Valter and colleagues showed that fasting ‘protects normal but not cancer cells against high-dose chemotherapy’.
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They followed this with another paper in which they showed that fasting increased the efficacy of chemotherapy drugs against a variety of cancers.
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Again, as is so often the case, this was a study done with mice. But the implications of Valter’s work were not missed by an eagle-eyed judge called Nora Quinn, who saw a short article about it in
The LA Times.

I met Nora in Los Angeles. She is a feisty woman with a terrific, dry sense of humour. Nora first noticed she had a problem when, one morning, she put her hand on her breast and felt a lump the size of a walnut under her skin. After indulging, as she put it, in the fantasy that it was a cyst, it was removed and sent to a pathologist.

‘The reality of your life always comes out in pathology,’ she told me. When the pathology report came back it said that she had invasive breast cancer. She had a course of radiotherapy and was about to start chemotherapy when she read about Professor Longo’s work with mice.

She tried to speak to Valter, but he wouldn’t advise her because none of the trials he had run, up to that point, had been done with humans. He didn’t know if it was safe for someone about to undergo chemo to fast and he certainly wasn’t going to encourage people like Nora to give it a go.

Undeterred, Nora did her own research and decided to try fasting for a seven-and-a-half-day, water-only fast; it would cover before, during and after chemotherapy. Having discovered how tough it can be to do even a
four-day
fast while fully healthy, I’m surprised she was able to go through with it, though Nora says it’s not so hard and I’m just a wimp. The results were mixed: ‘After the first chemo I didn’t get that sick, but my hair fell out.’

So next time she didn’t fast, and she was only medium
sick. ‘I thought it wasn’t working. I thought, seven and a half days of fasting to avoid being medium sick, this is a really bad deal. I am so not doing that again.’

When it was time for her third course of chemo, she didn’t fast. That, she now feels, was a mistake.

‘I got sick. I don’t have words for how sick I was. I was weak, felt poisoned, and I couldn’t get up. I felt like I was moving through jello. It was absolutely horrible.’

The cells that line the gut, like hair root cells, grow rapidly because they need to be constantly replaced. That’s one reason why chemotherapy can make people feel really ill.