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Could fasting be good for us?

Radical diet ... intermittent fasting found to have health benefits.

Radical diet ... intermittent fasting found to have health benefits.

Fasting for your health’s sake never seemed smart to me.  Why starve for a day or so in the interests of detoxing, for instance, when there’s no real evidence that it works?  Then there’s those sinking blood sugar levels – a cause of grumpiness, energy dips and wavering concentration.

But what if short regular bursts of fasting could do us some good in other ways – by shoring up our defences against heart disease, diabetes or Alzheimer's? Fasting might carry the taint of fringe medicine but it’s also the subject of serious research, with some scientists suggesting it may reduce chronic disease, a theory stemming from studies that underfeeding leads to a longer life - at least if you’re a rat. 

“We forget that three meals a day with snacks in between hasn’t exactly been the norm throughout human history..” 

In the US, researchers at the National Institute on Ageing in Baltimore have found that restricting food - again in rats – is good for their brain cells. It helps boost levels of a substance called BDNF – short for brain-derived neurotrophic factor – thought to help protect human brains from Alzheimer’s disease. (Exercise may have the same effect too – but that’s another story).  

Meanwhile at the University of Adelaide’s Discipline of Medicine, research scientist Leonie Heilbronn is trying to find out if fasting every other day can help reduce cardiovascular disease in humans. The story so far is that intermittent fasting, as it’s known, lowers levels of cholesterol and other blood fats called triglycerides. What Associate Professor Heilbronn wants to nail down is what causes this effect – is it the fasting itself or any weight loss resulting from it?

“Studies are showing that fasting has health benefits in humans, but we also need to find out if people can actually do it – some people can get very grumpy,” says Heilbronn who, as her own guinea pig in a previous study, tried fasting herself. While she coped, some found it challenging. 

In her study, fasting means eating just one meal a day – an early breakfast before 8am. These fasting days alternate with days of eating normal meals.  If this kind of food restriction seems extreme, it’s because we forget that three meals a day with snacks in between hasn’t exactly been the norm throughout human history, especially for our hunter gatherer ancestors. 

“We’re more geared for feasting and famine,” says Heilbronn.

Nor was it unusual – and still isn’t in some communities –for people following religious calendars to fast or at least eat less at certain times of the year.

So could old fashioned fasting turn out to be an antidote to modern over eating?

It wouldn’t surprise Katherine Samaras, head of Diabetes and Obesity Clinical Studies at Sydney’s Garvin Institute of Medical Research. 

“There’s evidence that people who follow seasonal fasting, such as that embedded in the older faiths, live longer - this is after controlling for other factors like alcohol consumption, smoking and other lifestyle factors,” she says.

Still, it’s early days with this research and we’re a long way off prescribing regular fasting for anyone for the sake of their heart or brain but it does give food for thought – or should that be less food for thought?

“There are a number of important messages we can take from these research findings,” says Associate Professor Samaras. “The first is that we shouldn’t chronically overeat, even if we are maintaining a healthy weight. The second is that it’s not unreasonable to periodically eat a bit lighter than usual. 

“The third and perhaps most important is that studies in humans suggest that the health benefits of fasting  were obtained by light, restricted eating, and not the sort of faddish longer term fasts of three days or more which can result in dangerous shifts in blood minerals and excessive loss of muscle mass.”

Have you tried fasting?

42 comments so far

  • Every 3rd day I fast. Hunters in the olden days used to do it while they were out hunting animals as it cleared their mind and made them more efficient predators. I studied this extensively while in transit.

    Devout Lutheran
    Date and time
    May 09, 2012, 10:36AM
    • Yep, this seems like a good idea. There is increasing research that you get the benefits of calorie restriction by eating normally, and practising intermittent fasting. And it feels good, too.

      Date and time
      May 09, 2012, 11:41AM
    • Yeah great idea on those days in the office people take the long way around your desk so they don't get caught in one of your animal traps. People you meet wonder why you started salivating when they talk to you. You start to think children are not only cute but tender. And when you get home from work your pets refuse to stop hiding from you.
      There is so much need for the hunter instinct in today's consumerist society.

      Cook Cook
      Date and time
      May 10, 2012, 8:42AM
  • Fasting helps us gain our ideal body mass and affects the fat burning metabolism of our perfect machines. As an amateur body bulder I see it as my responsibility to maintain a perfect figure to inspire people of larger-than-usual mass to work towards their goal. Perfect aesthetics is something we should all strive for.

    formerly of Florence
    Date and time
    May 09, 2012, 10:41AM
    • Here's a hint, might cure you of that blighted narcissism: NO ONE CARES. No-one is impressed. Sorry! =D

      Ms Anthropist
      Date and time
      May 10, 2012, 7:57AM
    • Something tells me 'David's comment was tongue in cheek

      Date and time
      May 10, 2012, 8:27AM
  • Yes I have tried IF, it is a great way of increasing the pleasure of a meal, because you know how good stuff tastes when you are ravenous. The benefits you mention are a little hard to test. If you have been on a carb based diet I think the effects will be a lot of discomfort as you will feel the lack of regular sugar hits, probably feeling really unplugged or lacking energy..if you have a carb restricted diet and have adapted to burning fat missing a meal is no big deal, and these days I can miss them without discomfort, though after 12 hrs everything smells delicious. Food was never as certain as it is in the modern era, it is natural to go for short periods like a day without eating.

    Lean Too
    Date and time
    May 09, 2012, 11:29AM
    • Really? I find if I eat protein I need carbs, potatoes veggies or rice to help it go down or I'm hungry a half hour later and feel like crap. Carbs satisfy me long term.

      Currently IF now. Ate a chocolate muffin, and a latte for breakfast haven't eaten for 12 hours and feel fantastic. Could easily go 24 more hours. If I was to say eat eggs for breaky I would be tired after 20 minutes and need to eat.

      BIG PROBLEM tho, while exercise should be done on an empty stomach you can't do it on a fast. Your body will release heaps of cortisol which will make you stressed and burn out your muscles.

      In hindsight IF really means say pushing breakfast back to 1 o'clock. Gives the body the night to digest and the morning to get going and undertake cellular repair.

      Date and time
      May 10, 2012, 6:44PM
  • I fast once a week for 24 hours and skip breakfast another day to go paddling. Never get ravenous, probably because I follow a high-fat, low-carb diet

    Date and time
    May 09, 2012, 12:02PM
    • "not the sort of faddish longer term fasts of three days or more which can result in dangerous shifts in blood minerals and excessive loss of muscle mass"

      Utter bollocks. I have done 10 days fasts and periodically do 3-4 day fasts having nothing but vergetable/fruit juice to maintain vitamin & mineral intake.

      Muscle mass is not lost although lots of excess fat is. I always end the fast feeling fantastic, sleeping better and the first meal of roast vegetables to break the fast is like manna from heaven.

      Done properly fasting is fantastic and can be done for longer periods than a day.

      I agree it probably helps to be relatively healthy prior to the fast and not leap from a McDonalds diet into a fast. For what it is worth I tend to follow a paleo diet as much as possible.

      Fasting does give you an immense appreciation of real food. Is interesting that all I crave is nice roast vegetables - I do not crave fat sugary foods while fasting at all nor meat or grains.

      To note that the cravings are quite manageable and barely noticeable while fasting properly. It's not like I spend the entire time thinking about food. It is quite liberating mentally just doing away with the need to eat for a few days. Juices take only a few minutes to prepare.

      I also walk 4-5 kilometres per day and/or go to work while fasting so you can still be relatively active - although serious cardio is a no no obviously.

      Date and time
      May 09, 2012, 12:12PM

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