INTERMITTENT FASTING AND CALORIE RESTRICTION - WHAT I'VE LEARNED

(Read about my 12 month's experience of IF here. Which caused my excellent blood results here!) 

Last week I was invited to address my local Humanist group (Taunton Humanists) on the subject of Intermittent Fasting (IF) - here are my notes for the talk I gave:

In the 1930s, studies on mice discovered that calorie restriction (CR) resulted in longer-living, thinner, healthier mice

( http://tpx.sagepub.com/content/37/1/47.full.pdf )

…and many studies since have confirmed this finding with a variety of animals – rats, rhesus monkeys, worms – and even yeast!

Around the middle of the last decade several scientist/researchers in the US and in Manchester here, revisited this research and began their own studies.

In August 2012 Dr Mike Mosley’s Horizon programme ,which investigated current US research into longevity, Calorie Restriction (CR) and Intermittent Fasting (IF), was broadcast.

(Here’s a review by Brad Pilon, author of Eat, Stop, Eat, who has been practicing IF since 2006. His is a website well worth browsing!

Dr Mosley first of all looked at CRONies (calorie restriction with optimum nutrition) who averaged 1900 calories per day as against the recommended 2500 calories (for men). He met a representative of this group, a 50-yr-old who turned out to have the body of someone in his twenties.

However, restricting calories every day is extremely difficult to maintain.

Then he looked at fasting for 3-4 days at a time. This produced similar results to the CRONie regime, but had to be repeated every couple of months

Then he looked at three modified fasting regimes - ADF/4:3/5:2 [I spoke about all these briefly] – in turn, and concluded that 5:2 was the regime most suited to today’s lifestyles.

5-6 weeks of 5:2ing made a great impact on his metabolism. To take one example, his insulin level – which was just above the danger level for diabetes at the beginning – was now in the middle of the recommended range. All the other metabolic health indices showed similar improvements.

What happens to the body when we fast?

First and foremost, we lower the level of IGF-1 (insulin-type growth factor one) in our bodies.  When IGF-1 levels drop – as happens in a fast state – the body slows production of new cells and instead repairs old ones. This is “autophagy”*, a word derived from the Greek for “self-eating”.

http://www.dailymail.co.uk/health/article-2098363/Fasting-help-combat-cancer-boost-effectiveness-treatments.html

[This was posted on the Mumsnet Tips and Links thread]

"...by a curious coincidence I used to work on the receptor for that hormone! 

The receptor for IGF1 is massively overproduced in many cancers, with the result that the cancer cells are very responsive to the hormone, thus growing faster than normal cells. This links in with the IGF1-deficient people featured in the Horizon documentary; they don't produce the hormone and so don't grow large, but they also don't develop full-blown cancer. I think that's because even if they did develop cancerous cells, they wouldn't get the chance to grow fast because there's no hormone about.

In the documentary there was some mention of the fact that decreased protein intake led to decreased production of IGF1, thereby driving the body into 'fix-it' mode rather than 'growth' mode (these aren't official terms, I'm paraphrasing). So logically those people who are doing this for health benefits such as increased production of neural cells probably ought to reduce protein intake, or at least not have too much of it for the last meal of the day.





Dr Mark Mattson is an expert on BDNF (brain-derived derived neurotrophic factor). As you fast you cause the bodies cells to self-repair – but fasting also causes new brain cells to grow. So fasting will delay the onset of age-related brain deterioration.

Mark Mattson:

“These responses are based on our recent animal and human studies:

1. A complete fast (no food) with hydration maintained with non-caloric beverages will be superior to consuming 600 calories on the fasting days.


2. Eating the 600 calories at one meal will be superior to eating several smaller meals spread throughout the day. By eating only one meal, the body goes essentially 24 hours with no food. This results in adaptive cellular stress responses which we believe is particularly good for the brain.


3. In the case of the 5:2 diet, we do not know whether better health benefits are realized with two consecutive days of fasting versus any two days of fasting during the week.

So let’s cut to the chase: it would be much better if you could just get through a fast day without eating at all. Obviously, very few people are able to, or want to go for 36 hours without food. So if you are going to eat a (600 for a man, 500 for a woman) calorie reduced meal, you are much better to consume that as one meal than to spread those calories throughout the day.
This is because the stress produced by going for 24 hours without actually has identifiable positive brain responses such as the growth of new brain cells. It’s like a workout for the brain. How to add that into an intermittent fasting or alternate day plan?

Easy. Either, take a note of what time you last ate on the feed day prior to your fast and then do not consume your 600 calorie fast day allowance until 24 hours has past. So, if you ate at 6pm on a feed day, do not eat your 600 calories until 6pm on the fast day. That way, you’ve gone 24 hours without food AND you get to eat (albeit a restricted) dinner! If that doesn’t grab you, eat breakfast on a fast day and then don’t eat again until your breakfast the next day.”

(Mark Butcher got this response from Dr Mattson when he emailed him (along with Drs Mosley, Longo and Varady)

*Autophagy:

Decreases unnecessary cellular processes during starvation or fasting

Rids the cells of clutter, which causes aging of cells and the body

Performs cellular remodeling, which is a form of internal spring cleaning

Suppresses cancer and tumor formation by blocking over-proliferation of cells

Destroys microbes and other infectious elements of cells

Regulates our immune system to fight future infections

Supplies us with energy during times without food

As a result, autophagy reduces:

Cancer

Insulin resistance

Infections

Aging

Heart Disease

Neurodegenerative diseases (Parkinson, Alzheimer’s, etc.)

Inflammation

Here's an excellent quote from Brad Pilon:

Basically, fasting gives your body a chance to house-keep,” he says. “Constant growth is not a good thing. There must be time for recovery and rebuilding at a cellular level if optimal health is the goal

My story (here I tell the tale of my experiences with IF over the past 12 months)

The great majority of fasters report that fasting gets progressively easier the more you do it. Generally, the feeling is of great surprise that it is as easy as it is!

Finally, as Dr Mosley says in his book, it’s better if you have some company when you start fasting – or join an online forum. Here are two that I can thoroughly recommend:

The FastDay Forum and website

And:

The current Mumsnet 5:2 thread. The opening post on this thread is an absolute mine of information on this subject. There are other associated threads on weight maintenance, exercise, inspirational stories, etc, here.

There are literally thousands of poster on these forums who are not only successfully losing weight but are reporting better health in all regards.

Summary: This eating regime is not a diet – this is the way naturally thin people eat - feasting at times and other days not eating much at all!

And it mimics the fact that we are adapted to alternating periods of fasting by our likely evolutionary history. [When people are quick to dismiss the diet as a fad, it's good to remind them that a way of eating that mimics patterns that existed for hundreds of thousands of years isn't really faddish.]

Our species had to survive through periods of global cooling, in temperate areas where food is scarce for long periods. On many days, the only available food might well have been a few scraps from the previous day. The real dietary "fad" is unlimited access to food, 24/7, with zero effort involved to get it.

There are many inspirational posts on the two forums I recommend above – but I’ll just include the one:

Hi there - I have just found the forum, and am thrilled that there are so many 5:2 ers out there! My husband and I have been fasting for almost 6 months with amazing results. Weight loss has been steady at about 2 pounds a week mostly, so I have lost one and half stone from 11 st 11lbs to 10 st 3 lbs and my husband from 16 st 10 lbs down nearly 3 stone to 13 st 12 lbs. BUT - we didn't really go on it for the weight loss - I have a chronic pain/fatigue condition (so of course weight loss was important too), and my husband …has chronic renal failure and was nearing dialysis. The effects of the 5:2 have been amazing - my pain and fatigue has reduced considerably, and I am much lighter and 'nimbler' on my feet. The absolutely amazing thing though is that my husband’s kidney condition is improving (and he had been told it was a definite deterioration towards dialysis/transplant). His eGFR (estimated glomerular filtration rate) in November was 17.9% and on his last visit to the consultant in February it had risen to 21.4% - too much to be just a blip or variation in measurements. We are looking forward to his next results. Perhaps this is the cellular regeneration happening triggered by the drop in IGF. We are so excited, it has given us another year before dialysis has to begin (if at all!!)”

Other associated links:

http://www.healthyfellow.com/511/alternate-day-fasting-interview-part-1/

(Interview with Dr Krista Varaday)

http://www.cavemandoctor.com/2012/04/06/autophagy-turning-stress-into-health/

(Guide to autophagy)

http://gettingstronger.org/2011/05/intermittent-fasting-for-health-and-longevity/

(IF explained in very clear language in 6 short videos)

http://www.precisionnutrition.com/intermittent-fasting

(Experiments in IF by a MD)

http://vimeo.com/44450267

(The men who made us fat – BBC – part one of three)

http://vimeo.com/44450267

http://www.medichecks.com/index.cfm?s=5&d=6

(Sister and brother blogging about their experiences with IF – and logging their IGF-1 at intervals)