BBC: Intermittent fasting: The good things it did to my body

kendrafallon

The article can be found at: http://www.bbc.co.uk/news/magazine-25549805

3 January 2014 Last updated at 00:23

Intermittent fasting: The good things it did to my body
By Peter Bowes BBC News, Los Angeles

Many of the changes in my body when I took part in the clinical trial of an intermittent fasting diet, were no surprise. Eating very little for five days each month, I lost weight, and I felt hungry. I also felt more alert a lot of the time, though I tired easily. But there were other effects too that were possibly more important.

During each five-day fasting cycle, when I ate about a quarter the average person's diet, I lost between 2kg and 4kg (4.4-8.8lbs) but before the next cycle came round, 25 days of eating normally had returned me almost to my original weight.

But not all consequences of the diet faded so quickly.

"What we are seeing is the maintenance of some of the effects even when normal feeding resumes," explains Dr Valter Longo, director of USC's Longevity institute, who has observed similar results in rodents.

That was very good news because that's exactly what we were hoping to achieve."

Clinical tests showed that during the diet cycles my systolic blood pressure dropped by about 10%, while the diastolic number remained about the same. For someone who has, at times, has borderline hypertension, this was encouraging. However, after the control period (normal diet), my blood pressure, like my weight, returned to its original - not-so-healthy - state.

The researchers will be looking at whether repeated cycles of the diet could be used to help manage blood pressure in people over the longer term.

Arguably, the most interesting changes were in the levels of a growth hormone known as IGF-1 (insulin-like growth factor). High levels of IGF-1, which is a protein produced by the liver, are believed significantly to increase the risks of colorectal, breast and prostate cancer. Low levels of IGF-1 reduce those risks.

"In animals studies we and others have shown this to be a growth factor that is very much as

sociated with ageing and a variety of diseases, including cancer," says Longo.

Studies in mice have shown that an extreme diet, similar to the one I experienced, causes IGF-1 levels to drop and to stay down for a period after a return to normal eating.

My data showed exactly the same pattern.

"You had a dramatic drop in IGF-1, close to 60% and then once you re-fed it went up, but was still down 20%," Longo told me.

Such a reduction could make a significant difference to an individual's likelihood of developing certain cancers, he says. A study of a small population of people in Ecuador, who have much lower levels of IGF-1, because they lack a growth hormone receptor, showed that they rarely develop cancer and other age-related conditions.

My blood tests also revealed that the major inhibitor of IGF-1, which is called IGFBP-1, was significantly up during the fasting period. Even when I resumed a normal diet, the IGFBP-1 level was elevated compared with my baseline. It is, according to Longo, a sign that my body switched into a mode that was much more conducive to healthy ageing.

Data from other participants in the study is still being analysed, but if they also show lower levels of IGF-1 and higher levels of IGFBP-1, it could help scientists develop an intermittent fasting regime that allows people to eat a normal diet for the vast majority of the time, and still slow down the ageing process.

One idea being explored by Longo is that a five-day intervention every 60 days may be enough to trigger positive changes in the body.

"This is exactly what we have in mind to allow people, for let's say 55 every 60 days, to decide what they are going to eat with the help of a good doctor, and diet in the five days. They may not think it is the greatest food they have ever eaten, but it's a lot easier, let's say, than complete fasting and it's a lot safer than complete fasting and it may be more effective than complete fasting."

The very small meals I was given during the five-day fast were far from gourmet cooking, but I was glad to have something to eat. There are advocates of calorie restriction who promote complete fasting.

My blood tests also detected a significant rise in a type of cell, which may play a role in the regeneration of tissues and organs.

It is a controversial area and not fully understood by scientists.

"Your data corresponds to pre-clinical data that we got from animal models that shows that cycles of fasting could elevate this particular substance, considered to be stem cells," said Dr Min Wei, the lead investigator.

The substance has also been referred to, clumsily, as "embryonic-like".

"At least in humans we have a very limited understanding of what they do. In animal studies they are believed to be 'embryonic-like' meaning... they are the type of cells that have the ability to regenerate almost anything," says Longo.

t would be highly beneficial if intermittent fasting could trigger a response that enhances the body's ability to repair itself, but much more research is required to confirm these observations.

This diet is still at the experimental stage and data from the trial are still being studied. Other scientists will eventually scrutinise the findings independently, and may attempt to replicate them.

"We generally like to see not only an initial discovery in a trial but we like to see confirmatory trials to be sure that in the broadest kind of sense, in the general population that these findings are going to be applicable," says Dr Lawrence Piro, a cancer specialist at The Angeles Clinic and Research Institute.

"I do believe fasting to be a very effective mechanism. They are pieces of a puzzle, that puzzle is not fully revealed yet, the picture isn't clear yet but there's enough of the picture clear. I think we can be really excited that there is some substantial truth here, some substantial data coming forward and something that we can really be hopeful about."

Future clinical trials will focus on "at-risk" members of community - those who are obese - to gauge their response to a severely restricted diet.

But if this diet, or another intermittent fasting diet, is eventually proven be effective and sustainable, it could have profound implications for weight loss and the way doctors fight the diseases of old age.

This is the third part of a series. See also: Fasting for science (http://www.bbc.co.uk/news/magazine-25498742) and Sitting out the hunger pangs (http://www.bbc.co.uk/news/magazine-25498743).

Peter Bowes

The popularity of intermittent fasting has grown over the past year or so. The 5:2 diet, which involves dramatically reducing your calorific intake on certain days of the week, is one example. But more clinical data is needed to confirm the benefits of such regimes.

I. I love to eat. I enjoy a big, healthy breakfast, exercise a lot and - left to my own devices - snack all day before digging in to a hearty evening meal.

Insulin-like growth factor 1

IGF-1 is a protein produced by the liver when it is stimulated by growth hormone circulating in the blood
It plays a role in the growth of muscle, bones and cartilage throughout the body, and is critical to growth and development during childhood
Lower levels of IGF-1, induced by calorie restriction, have been shown in rodents to slow the ageing process and protect against cancer
IGF-1 levels in adult humans vary according to age and gender

jetlag

No way I could fast for 5 days in a row, but the results are interesting (and nothing new) but it's good to see more studies going on.

mumblemagic

I would have liked to know of any downsides - the article reads more like an advert and a minor stab at the scientist's seeming hypocrasy than a balanced journalistic peice.

Anyone have any further information?

FP4HSharon

I would have liked to know of any downsides - the article reads more like an advert and a minor stab at the scientist's seeming hypocrasy than a balanced journalistic peice.

Anyone have any further information?

On the downsides...research shows IF produces amazingly good results for men of any size and OBESE women. HOWEVER, if a woman is NOT obese, then it actually has negative health effects. You can read the details at this article...

http://www.paleoforwomen.com/shattering-the-myth-of-fasting-for-women-a-review-of-female-specific-responses-to-fasting-in-the-literature/

mumblemagic

I would have liked to know of any downsides - the article reads more like an advert and a minor stab at the scientist's seeming hypocrasy than a balanced journalistic peice.

Anyone have any further information?

On the downsides...research shows IF produces amazingly good results for men of any size and OBESE women. HOWEVER, if a woman is NOT obese, then it actually has negative health effects. You can read the details at this article...

http://www.paleoforwomen.com/shattering-the-myth-of-fasting-for-women-a-review-of-female-specific-responses-to-fasting-in-the-literature/

Thanks, that's really interesting. Wasn't considering intermittent fasting anyway, but now I'm definitely avoiding it!

justinproulx1

I love intermittent fasting seen great results with it. But i do it with 12 hour windows not 5 days. thats ridiculous

kagevf

i do IF everyday 16:8 . i like to eat anything without gaining weight. its not for everyone. you can still lose the weight by being on deficit. but i like my ice cream , chocolates and pizza .

mumblemagic

i do IF everyday 16:8 . i like to eat anything without gaining weight. its not for everyone. you can still lose the weight by being on deficit. but i like my ice cream , chocolates and pizza .

Yeah, I like Ice cream, chocolate and pizza too! I've been in a plateau for a while (holiday + stress + xmas = eating more and exercisign less than I need to do lose weight), but when I was losing weight I was still able to eat all those things, providing I built it into my day with a run and/or healthier food the rest of the time.

Dragonwolf

I would have liked to know of any downsides - the article reads more like an advert and a minor stab at the scientist's seeming hypocrasy than a balanced journalistic peice.

Anyone have any further information?

On the downsides...research shows IF produces amazingly good results for men of any size and OBESE women. HOWEVER, if a woman is NOT obese, then it actually has negative health effects. You can read the details at this article...

http://www.paleoforwomen.com/shattering-the-myth-of-fasting-for-women-a-review-of-female-specific-responses-to-fasting-in-the-literature/

Thanks, that's really interesting. Wasn't considering intermittent fasting anyway, but now I'm definitely avoiding it!

One thing to note on that is that the few studies that do involve women are alternate-day fasting. Many women have reported that they don't have the problems mentioned in the studies, likely because they're doing 16:8 ("leangains") IF, and therefore not going full days without eating.

IF is generally just a different way of allocating calories. Over the course of the week, most people consume the same amount whether they're IFing or not, it's just a difference of when those calories are consumed. The result is that you can eat a high-calorie food, such as pizza or ice cream, and not have to worry about going over your calorie allotment (particularly if you're a small person with a lower average daily calorie allotment), either because you're eating two-days worth of food in one day, or because you're eating a day's worth of food in a half a day (or less).

ItsCasey

I would have liked to know of any downsides - the article reads more like an advert and a minor stab at the scientist's seeming hypocrasy than a balanced journalistic peice.

Anyone have any further information?

On the downsides...research shows IF produces amazingly good results for men of any size and OBESE women. HOWEVER, if a woman is NOT obese, then it actually has negative health effects. You can read the details at this article...

http://www.paleoforwomen.com/shattering-the-myth-of-fasting-for-women-a-review-of-female-specific-responses-to-fasting-in-the-literature/

Some women - in fact, some men - have difficulty with intermittent fasting. Some don't. I've been practicing various forms of IF for more than 2 years, and I do not have irregular periods or sleeplessness or any of the other problems the Paleo blog mentions. The problem is that there will inevitably be people who participate in these studies who just aren't suited to it, but they keep doing it anyway, and it causes all sorts of peripheral stress in their bodies.

Any regular practitioner of IF will tell you that it works for some and not for others. If you're interested, you should try it, and be open to the fact that it's not a test of strength or willpower. There is no pass or fail. It's either something you like and that works for your lifestyle and eating preferences, or it's something you don't like and just leaves you hungry and moody all the time.

There are definitely people who abuse IF by going completely off the dietary rails for a weekend, then fasting for 36 or 48 hours, and calling that IF. I have never seen an IF protocol that promotes that sort of crime-and-punishment behavior, but there are certainly well-known fitness professionals who do it, which causes people to think that's what intermittent fasting is about.

And I have never heard of a 5-day fast. I think the most that the well-known IF protocols recommends is 24 hours (Eat Stop Eat).

Katosan63

I would have a lot of trouble fasting for 5 days in a row myself but I have had success on the 5:2 plan (2 days of 500 cal 5 days 2,000.) I'm a 50 yr old woman and I've lost 12lbs since Halloween and only gained a few lbs over the holidays and it's 1-3-14 and I'm back on track with only one fast day since 12-19-13. Good luck!

Fitmom4boys

I was playing around with IF before the holidays and had dropped 2 lbs and I had been stuck forever! I am going to try to program in 2 days a week iIF type of plan....and stick to a lifing / running plan too! I hate eating breakfast so the IF days are not at all hard to pull off!