One man went to enormous lengths to reduce the width of his girth. Dr Karl weighs up the effects of fasting on the body.

Extreme weightloss: treating obesity by total starvation can be dangerous

Back in June of 1965, a Scotsman weighing 207 kilograms, described as “grossly obese” and hereafter known only as Mr A B, turned up at the Department of Medicine at the Royal Infirmary in Dundee.

He was sick of being fat and wanted to lose weight by eating nothing and living off his body fat. He told the hospital staff he was going to fast flat out, whatever they said, so they may as well monitor him along the way.

He ended up fasting for one year and 17 days that’s right, he ate no food at all for over a year. He lived entirely off his copious body fat, in the end losing about 125 kilograms of weight.

Treating obesity by total starvation can be dangerous. There are many reports of total starvation leading to death. For example, some people have died of heart failure during the fast, while another died on the 13th day of his fast from small bowel obstruction. Some people have died during the re-feeding period after the fast one from lactic acidosis.

But to counter this, going hungry is natural. Humans like us (that’s Homo sapiens) have been around for the last 200,000 years and for most of that time, food was not always at hand. We evolved to survive with not enough food. Some studies actually show that fasting (or at least, calorie restriction) can have health benefits under certain circumstances.

Once you stop eating, your body gets its energy from the glucose in your bloodstream and liver, thanks to your last meal. You carry a semipermanent 0.5 to 1 kilogram of solids in your gut. The glucose from this runs out after about eight hours.

Then you start burning up a chemical called glycogen. Glycogen is simply a whole bunch of glucose molecules loosely stuck together. It’s stored in your liver and muscles. Glycogen is really easy to break down into the individual glucose molecules from which it was made. You can burn glycogen to get the glucose you need for about another 36 to 48 hours.

After two or three days of fasting, you get your energy from two different sources simultaneously. A very small part of your energy comes from breaking down your muscles but you can avoid this by doing some resistance training, otherwise known as pumping iron. The majority of your energy comes from breaking down fat.

But very soon, you move into getting all your energy from the breakdown of fat. The fat molecules break down into two separate chemicals glycerol (which can be converted into glucose) and free fatty acids (which can be converted into other chemicals called ketones). Your body, including your brain, can run on this glucose and ketones until you finally run out of fat.

The average non-obese 70-kilogram male carries about 8,000 kilojoules of energy in glycogen, and about 400,000 kilojoules in his body fat.

In the case of our big Scotsman, Mr A B, the staff in the medical school at the University of Dundee kept a close eye on him. He did not eat any food, but the staff gave him yeast for the first 10 months and multi-vitamins every day. Potassium is essential for the proper working of the heart, and when his potassium levels got a little low around the 100-day mark, he was given potassium tablets for about 70 days. He defaecated infrequently, roughly every 40 to 50 days.

Blood samples were taken every fortnight, and his carbohydrate metabolism was checked on nine occasions during the 382 days of his fast. Surprisingly, for the last eight months of his fast, his blood glucose levels were consistently very low. They were around two millimoles, which is about half of the bottom end of the normal range. Even so, he did not suffer clinically from this abnormally low blood glucose level.

His weight dropped from 207 kilograms to 82 kilograms. Some five years later, he had regained only 7 kilograms.

In humans, fasting seems to have health benefits for high blood pressure, diabetes, asthma and epilepsy in children. In animals, fasting seems to reduce the cognitive decline that happens in conditions such as Parkinson’s disease and Alzheimer’s disease.

One problem with fasting is that you can get cranky and irritable (and sometimes hungry). Another is the lack of companionship with your fellow humans. After all, the word ‘companion’ comes from the roots ‘com’ meaning ‘with’ and ‘panis’ meaning ‘bread’. If you spend lots of time not sharing meals with your kith and kin, you run the risk of becoming an outsider.

So to keep your friends, continue breaking bread just don’t eat it.

Tags: obesity, anatomy

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Published 24 July 2012

2012 Karl S. Kruszelnicki Pty Ltd

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24 Jul 2012 8:47:21pm

Did he drink water while he was fasting? If so, how much? Was it irregular amounts?

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25 Jul 2012 10:02:37am

Hi Chris, yes he was given water, along with all the electrolytes the human body requires, that he wasn’t getting from the food. Not sure of the amounts though, check out marksdailyapple.com for interesting articles on water consumption.

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25 Jul 2012 12:23:18pm

He’d have to be drinking more water than your average person, because the human body gets the majority of its water from food.

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25 Jul 2012 2:53:49pm

It’s unlikely he would have survived very long without drinking water, despite the lypolisis process liberating some water.

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26 Aug 2012 2:13:17pm

he did have water, just not food.

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25 Jul 2012 1:06:21pm

Excellent and well timed article.

It is now the month of Ramadan the month of fasting for 1.3 billion Muslims around the world or so where they fast from dawn until sunset.

Truly an amazing collective feat…

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26 Jul 2012 12:43:55pm

Not really – the overwhelming majority more than make up for the day-time fast by over-eating after sunset – not a healthy action.

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29 Jul 2012 9:07:20pm

thats not fasting

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03 Aug 2012 12:38:24am

I seriously do not get the connection between a bloke who didn’t eat for over a year to people over eating each night for a month.

I know how it works, I have Muslim friends.

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16 Aug 2012 1:47:09pm

What a joke that is to relate Ramadan to Fasting. Don’t eat while the sun is out, then pig-out? How about No eating at all for a day or two? It’s a farce.

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25 Jul 2012 3:55:04pm

The amazing amount of time and money dedicated to weight loss is testament to the degree of difficulty. Having saidthat,restriction of calories is the most important method of utilising stored fat for its biological purpose; to tide humans over times of decreased intake. If only people were not in such denial!

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25 Jul 2012 8:25:30pm

Thanks for another fascinating article Dr Karl.

There are three points that really stood out for me in the article;

1) Resistance training is very beneficial to fat loss & health – Anja Taylor from Catalyst presented some excellent information in a recent episode titled ‘Excercise is Medicine’.

2) An appropriate amount of healthy body fat is necessary for good metabolic function & is also life sustaining when food is scarce.

3) When loosing weight becomes an obsession, it can have a negative impact on personal relationships & social interaction.

The best thing to do is just avoid all the problems with obesity in the first place, by making good choices to eat healthy, enjoy regular excercise & continue ‘breaking bread’ with friends to help nurture a cheerful personality.

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26 Jul 2012 11:04:44am

How can one perform “Resistance training” when one is starving? Carbohydrates are needed for activity.

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26 Jul 2012 7:16:15pm

Hi Kevin,

The question you asked is a good one & the simple answer is…’with difficulty’.

However, in a starvation situation without any carbohydrate intake, Dr Karl pointed out that your body will get all its energy from the breakdown of fat.

So, it’s the breakdown of fat that will give you the energy to do the ‘resistance training’ that will in turn prevent your muscles from breaking down. In a survival situation, ‘resistance training’ will probably be in the form of ‘looking for food’ rather than pumping weights.

Kind regards,

P.S. Sorry for the atrocious spelling mistakes in my previous message;
excercise should be spelt – exercise
loosing should be spelt – losing

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28 Jul 2012 12:03:20pm

Easily. The body will slip into ketosis and convert fat into ketones which the brain and heart find easier to use. This is why there are positiv aspects. You can do the same by restricting your carbs to less than 20g per day. There is ZERO need for carbohydrates in the human diet as the body can produce what it needs by way of glucose from gluconeogenesis in the liver. This amounts to roughly 100g per day for the brain, then slowly reduces as the body become more keto adapted. In fact, not eating carbohydrates and increasing your fat intake is an excellent way to lower cholesterol. Ive been carb free for 1.5 years and my triglycerides are down to 71 from 252. I have the lipid profile of a 6 month old at 33.

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20 Sep 2012 1:18:55pm

Walt, I agree.

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29 Jul 2012 9:03:44pm

Carbohydrates are definitely NOT required for activity. An increasing number of athletes are finding they perform better on a low carb approach. “Bonking” as some call it, occurs because most athelets are fuelling their activity with glucose, which as you can see from Dr Karl’s article, accounts for a very small percentage of total energy storage in the body.

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25 Jul 2012 10:56:41pm

Three cheers for all this. How does it compare with comment that we shouldn’t miss meals?

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26 Jul 2012 2:46:57pm

Dear Dr Karl, fascinating article, I teach physical and emotional fitness and one thing i have been telling woman between the ages of 40-65 who cant lose weight and dont eat very much is not to eat too little because the body goes into starvation mode and retains all the food and doesnt burn it off, ( a fallback to our evolution from our cave days in case of famine). is this not accurate? I would love to get your thoughts on this if you are willing. I also worry about youth reading this and thinking they can do this method too. i add i realise this article would not be fully responsible for any thing like that if it were to happen.Plus im sure they like Coke too much anyway unfortunately.

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28 Jul 2012 9:09:37pm

Hi Glynis,
Maybe suggest induced ketosis to your clients? There’s a lot to be learned from keeping a 65% fat, 30% protein, 5% carb setup.

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13 Aug 2012 3:59:39pm

In the majority of cases, I believe this is an excellent approach.

Be mindful that clinicians, and Diabetes Australia are very cautious about such an approach. As far as I can understand it is primarily due to their concern about a diabetic having a hypo attack.Maybe because they don not believe most people do not monitor their blood sugar closely enough, even when implementing considerable dietary changes. This is why most still recommend a higher percentage of carbohydrates in a diabetic diet, including potatoes.

I have to add that I am a diagnosed Type 2 diabetic, and I have taken on board a low carb diet, with excellent results. I am working at eliminating my insulin resistance over time with the low carb diet causing change to the fat levels within the cells, which will take some time, from what I understand.

Bottom line, a dietary specialist or exercise trainer would be well advised to ensure that they provided appropriate caveats, when recommending a low carb diet to anyone. Particularly when they don’t know if the person is diabetic to start with.

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26 Jul 2012 3:31:37pm

I went on a diet and exercised and lost about 20 kilo’s then hit a sticking point where what I was doing didn’t lose the final few kilo’s. I did a one day a week fast which was not too hard and lost another 5 kilos and felt much better.

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26 Jul 2012 8:42:37pm

Using some google searches based on a hyman being 100watts/ hour which I hopefully remember correctly from listenin to Dr Karl.

I come up with near 42 days to burn 120 kg of fat. How did this guy conserve so much energy to last over 1 year on that ?

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27 Jul 2012 3:07:27pm

Fat contains about 38 kJ per gram.
In the process of losing his weight he used 125kg of fat to live on consuming 125000 * 38 = 4,750,000 kJ of energy.
At about half-weight point during his weightloss (weighing about 145kg) he would have needed about 13200 kJ per day to maintain his weight.
Dividing the 4.75 million kJ by 13.2 thousand gives the approximate number of days he needed to lose 125 kg, which is almost exactly 360 agreeing very well with the story.

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27 Jul 2012 11:00:14am

I became sick a year before the water scare in Sydney in the mid-nineties. All I could eat for a week was half a pear and half a bowl of cereal and dropped from high 80s to 78 kg (I am 184 cm). This means that I would have lost 500 kg if I had kept it up for a year (and remained active). The fat returned very quickly plus some more when I began eating normally again so I don’t think its a great idea. Losing it slowly with a better diet might be a better idea.

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28 Jul 2012 10:20:14am

Interesting article, and one made more personal because I was delivered at the Royal Infirmary 4 months earlier. 🙂

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16 Aug 2012 5:58:23pm

Some of the responses that I read in the comments section are a worry. Thank goodness Dr Karl and the like practice evidence based science/medicine.

Where do some people get their ideas from? Before people come on here and state their opinion as fact perhaps they should do some research from reputable sources on the matter.

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13 Sep 2012 5:11:24pm

He was given vitamins,electrolytes and Yeast. Surely these are foods in every other sense of the word, aren’t they?

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23 Sep 2012 6:28:52pm

Vitamins/electrolytes are no food as they are not used for energy.

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