When was the last time
you were on a fast, eating a lot less than normal? The time you had the flu? That
medical procedure that required a 12 hour fast, but delays extended it to 16
hours? Not much choice there, but have you ever deliberately chosen not to eat?
Well, a few readers are hearing about the concept of occasional or intermittent
fasting (IF) for good health and a long life. One big fan of the idea is Michael Mosely (see pic), who has written a book on the concept of IF. It got a “leg up” on the back of his TV documentary on IF.
5:2 eating
The idea is simple. Eat
normally, and healthily I presume, for five days and for two non-consecutive
days eat only 500-600 Cals (2100 – 2500 kJs). Proponents excitedly explain that
you will lose weight. No surprises there. Eat less food and we all lose weight.
But is there more to this?
Early this year there
appeared an interesting and balanced article in the Scientific American on IF. I recommend it to you as I won’t be repeating much
of its information. It mentions Mark Mattson, Institute of Aging in the US, who
has studied the area for many years and believes that IF is both brain and heart-protective. His work also suggests that periodic fasting might protect
the neurons, lowering the risk of Parkinson’s Disease and dementia. He thinks
that IF better mimics how we ate during most of evolution, and offers a
survival advantage. If you could go a few days without food, yet still gather
and hunt smart, you pass down clever genes. Most studies have been done on
laboratory animals. Even if they are encouraging, they aren’t persuasive.
IF not protective against cancer
A recent review of both regular fasting and IF in
humans found no protection against breast cancer, but an increase in the risk
of other cancers. Long-term Calorie restriction did see a non-statistical trend
to cancer protection in mice, but nothing to get excited about. Their
conclusion was to stick to what we have said for years: don’t get fat and eat
well. You can’t sell a book with that kind of advice.
**No proof that IF better that good wholesome eating**
One thing I can’t do is separate
the benefit of eating well and remaining a reasonable weight from the potential
benefits of doing that AND following the 5:2 or IF routine. I know my own Basal
Metabolic Rate is 1800 Cals (7500 kJs), done under proper laboratory
conditions. I might need 3000 Cals (12500 kJs) or more on a very active day. If
I eat less than a quarter of my needs on two days of the week, I just don’t
think I can be active as well.
Here is the constant problem we
face when trying to advise people of a so-called perfect health-enhancing diet –
we live too long. That is, too long to make an assessment of any new diet theory,
such as IF or the Paleo Diet. We would need many thousands of
people following a new non-traditional diet idea for 60-100 years to then be
able to say: “This diet, on average, will give you a lifespan of 120 years.”
The best we can do is observe
those that have eaten a specific style for hundreds of years and lived to a
good age, reasonably free of disease, and marry that with science of physiology
and aging. The traditional Japanese and Mediterranean diets are the most
realistic models we have at the moment.
What does it all mean?
Diet sensations come and
go, get recycled, repackaged and return because
diet ideas are a commodity. Emphasise a need or concern, supply a solution and
six months as a new diet book, with its accompanying cookbook. OK, so I’m not
excited by IF, mainly because I haven’t enjoyed hunger nor do I think well when
starving. I much prefer that we ate for nutrition, health, enjoyment, community
and prepared food for pleasure and discovery.
So, if you like the idea,
try it. I don’t think you will come to any harm. You probably won’t have the
energy to exercise much on the semi-fasting days. As I have said before, you
are your own boss. No evangelistic dogma from me. However, if you are an IF
devotee, I would really love to hear of your experiences.
IF may be considered
natural, but I think that eating when you are hungry, and drinking when you are
thirsty, also neatly fit into a natural philosophy.
3 comments:
Thanks for the article Glen.
I have been trialing IF for the last 2 months. When I am fasting I feel great, i have plenty of energy and even sleep better.
It is not always easy and I found that If you are not in good shape (Tired, run down, ill) it is not a good idea and has more negatives than positives. One advantage of IF is it highlights how much you eat habitually rather than through genuine hunger.
In contrast to me My wife tried it for a while as well and it did not suit her at all. She felt faint, felt agitated etc...)
So my opinion so far is horses for courses. and it is a complement to good diet and exercise not a easy substitute for it.
Cheers
David
Great article Glenn. I love Michael Mosley's shows, I always enjoy them immensely even if I don't necessarily agree with 100% of them. Something I wondered after watching the IF show, was whether or not WHEN his blood tests were taken affected the results. Ie, if 2 blood tests were taken, one at the end of his eating days, and one after fasting, would his blood test results show significantly different results?
The initial few days of doing Intermittent Fasting can be difficult as we will most probably be voracious a few hours before our feeding period starts. So that you can minimize this appetite and get away from hungers, we should drink a lot of water and chew some sugar less chewing gum. We should be able to resist the hunger with just a little bit of self-control. Intermittent fasting consists in having periods of fasting and periods of feeding. There are different ways of doing this. One of the most famous ways of Intermittent fasting is too fast for around 16-18 hours and then eat for 6-8 hours.
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