Please Explain Read online

  This book is dedicated to my mother and my father, who gave me life, love, libido and the licence to be myself.

  Table of Contents

  Cover Page

  Dedication

  Celery with Negative Kilojoules

  Near-Death Experience—The Living End

  Leprosy, Limbs and Lies

  Where Did the Day Go?

  Ovarian Cancer and Pap Smears

  It’s All a Bit of a Yawn

  Halley-less Comet

  Psychic Sleuth

  Sleepy Time High

  The CIA Made AIDS?

  The X-Chromosome eXplained

  She Smells Seasmells (Ozone)…

  How to Make a Wee Difference!

  Poisonous Potatoes

  ‘A Salt’ the Water to Make it Boil

  Is This Space Empty?

  Bacteria vs Virus

  Mashed Facts

  Mellow Yellow

  Oxymoron

  Galileo and the Leaning Tower of Pisa

  Can Diamond Cut It?

  Reincarnation—Again

  Women Speak More Than Men (It’s All Talk)

  Would You Like Dressing on That Wound?

  Hashish Assassin

  The Lion’s the Mane Man

  Mobile Phone Cooks Egg (Poaching the Truth)

  They Snow This, They Snow That…

  Push My Button

  The Gum and the Restless

  Moondance

  CSI—Bite the Bullet

  Silver Jubilee Book Launch, Bondi Beach 2006

  Acknowledgments

  Other Dr Karl titles

  Copyright

  About the Publisher

  Celery with Negative Kilojoules

  My teenage daughter and her friends were recently talking about ‘negative kilojoules’. They were curious about whether eating celery would make you lighter—supposedly because digesting celery requires more energy than is actually present in the celery. (As an aside, my teenage son would never have given negative kilojoules a thought in his whole life. Is this a generic boy–girl difference?) So I had to check out this ‘negative kilojoules’ theory.

  Even though I trained as a medical doctor, the lectures on Nutrition came to a grand total of only eight hours over the whole course. And because nutrition is a huge topic, I knew that that eight hours wouldn’t cut it. So I consulted the experts, the nutritionists who spend years studying this enormous body of knowledge. They told me that no-one had ever done an experiment where people were fed nothing but celery. This is partly because the volunteers would soon become ill on a diet totally lacking in proteins or fats and partly because celery has so few kilojoules that any measurements would be difficult to calculate.

  Negative kilojoules

  Celery is about 95% water, 2.2% digestible carbohydrates and 1.8% indigestible carbohydrates, as well as insignificant amounts of protein and fat.

  BUT there are a small number of kilojoules found in celery…not many…but there are some!

  The BMR is a measure of the amount of energy needed to keep you alive when you are resting, in a fasted state, lightly clothed and in an environment with a comfortable temperature.

  Basal Metabolic Rate—101

  One way to get to the bottom of this ‘negative kilojoules’ story is to look at the Basal Metabolic Rate (BMR)—a measure of the amount of energy needed to keep you alive when you are resting, in a fasted state, lightly clothed, and in an environment with a comfortable temperature.

  Technically, the Basal Metabolic Rate is a measurement of how many millilitres of oxygen you breathe in for every gram of body weight per hour. At rest, human beings typically breathe in about 0.3 ml of oxygen per gram of body weight per hour. Nutritionists measure the BMR by putting a volunteer in an airtight box and measuring how much oxygen they burn up and how much carbon dioxide they generate. These changes in oxygen and carbon dioxide are easy to measure when you consume a huge meal of steak and lots of potatoes—and almost impossible to measure when you have a small meal of a few sticks of celery.

  About 70% of your total daily energy expenditure is spent in keeping your organs running (e.g. liver, skeletal muscle, brain, kidneys and heart)—the BMR, while another 10% comes as a side effect of burning up your food. The remaining 20% comes from physical activity. You can see how, if you increase your exercise just a little and maintain the same food intake, you can lose weight. For example, walking uses about 2000 kJ per hour.

  Basal Metabolic Rate—102

  However most of us don’t think in terms of O2ml/gm/hr—we think in kilojoules.

  The ‘average’ man uses about 11 000 kJ per day, while women use around 8000. Of course, this will vary according to your weight, age, gender, coffee habit, exercise program, genes that your parents gave you, height, surface area, muscle mass—and yes, how much you eat.

  Back in 1918, J. Arthur Harris and Francis G. Benedict published their paper ‘A Biometric Study of Human Basal Metabolism’. They measured the BMRs for 136 men and 103 women and then did a ‘partial correlation coefficient analysis’ for any factors that might have an effect on BMR—a big task in the days before electronic calculators and computers. The equations—the original century-old ones for the total heat produced in 24 hours—are still a reasonable approximation:

  Men, H = 66.4730 + (13.7516 x W) + (5.0033 x S)—(6.7550 x A), Women, H = 655.0955 + (9.5634 x W) + (1.8496 x S)—(4.6756 x A),

  where H is the total amount of heat produced/energy burnt in 24 hours in kilocalories, W = weight in kilograms, S = height in centimetres, and A = age in years. To convert kilocalories to kilojoules, multiply by 4.2. (According to current wisdom in the book trade, each equation in a book reduces the sales by 50%. That’s why I’ve cleverly hidden these equations deep inside the chapter and bunched them up so that you can skim right over them and ignore them.)

  Food Tax Overview

  Surprisingly, just to digest an average meal, human beings increase their BMR by 50%—but only for about four hours. In other words, it costs energy to digest the meal. (This might be the basis of the ‘negative energy in celery’ myth.) Nutritionists call this extra energy the ‘Thermic Effect’—a kind of ‘Energy Tax’. It is also called the SDA (Specific Dynamic Action)—but whatever you call it, it takes energy to digest food.

  The question is—how much of the energy in the food is needed to digest it? To answer this, you need to know what your body does to get the energy out of the food that you eat.

  Food Tax Breakdown

  If you have ever eaten a tough steak, you might think that a lot of the energy that it takes to get the nutrition out of your food comes from chewing. But no, chewing the food takes only 1–2% of the total energy in the food. The vast majority of the extra energy needed to digest the food is burnt in the gut.

  Ultra-marathon Humans

  The sport called the ‘ultra-marathon’ can last up to six days. And the athletes taking part might not beat the Snake Kings of BMR for the highest BMR title, but they do amazing feats. An article in the journal Nature reported that the athletes ‘…Trek 125 kilometres, and cycle 250 more. Kayak 131, rappel through canyons for another 97, and swim 13 in churning whitewater. Throw in some horseback riding and rock climbing; spread it all over six days in the blistering Utah heat; and never stop to sleep.’

  One of the biggest of these events, the ‘Primal Quest Expedition Adventure Race’, has teams of four athletes, racing across some 700 km of very difficult terrain. The winning team gets US$250 000 in prize money.

  For some unknown reason, these athletes reach their ultra-marathon peak in their mid-30s—amazingly late in life for such a demanding sport. One theory says (with good evidence) that it helps a lot to get the ‘right’ genes from you
r parents. Another theory says (also with good evidence) that the brain of a good ultra-marathoner is heavily involved, for example, in coordinating all the different biochemistries from the overworked lungs, legs and other parts of the body.

  In one day, the athletes burn up 84 000 kJ of energy—about 10 times the ‘resting’ BMR of an average athlete. It’s very difficult to eat this much.

  About half of this energy is used in three stages. Some of the energy activates the muscles of your gut to mash up your food and push it along the 10-m length of your gut. This helps break down the food into small blobs ranging in size from a fingertip to the head of a matchstick. More of the energy is used to make special chemicals (enzymes) which further break the food down from little blobs into individual molecules. And in the third stage, more energy is used to pump these tiny molecules across cell membranes and into the cells that form the lining of your gut.

  The other half of the digestive energy is used inside the cells lining your gut. This energy is used to stitch together the very small molecules into bigger and more useful molecules. For example, individual amino acids get joined to make proteins.

  You might ask—why break the molecules down, only to build them up again? Because if only extremely small chemicals can get across the lining of your gut, bigger things (like bacteria and viruses) will find it really hard to invade. All of this activity—chewing food, breaking chemicals down and building them up again—temporarily increases your BMR from 1 to 1.5.

  Diversion—Kings of Metabolic Rate

  If human beings exercise really hard, for example in an Olympic 100-m sprint, they can crank up their total energy expenditure to 20 times normal—but only for 10 seconds or so. Horses, however, can do much better. In the Melbourne Cup, thoroughbreds can reach a BMR of 45 times normal for a few minutes.

  Snakes seem to be the Kings of Metabolic Rate—because of their enormous meals. Human beings might eat a meal equal to 1% of their body weight, but a snake can readily eat 25% of its body weight. When the Sidewinder Rattlesnake (Crotalus cereastes) does this, it can increase its Metabolic Rate up to 17 times normal. The Metabolic Rate reaches this peak about 24 hours after the snake has started to eat, and stays above seven times normal for about three days. No human beings could do this.

  There is a report of a Burmese Python (Python molurus) reaching a Metabolic Rate of 45 times its BMR after eating a meal equal to its own body weight.

  Snakes are also the Kings of Gluttony. It seems that the ‘record’ for a snakes’s meal is about 1.6 times its own weight!

  High Energy Burning

  Another animal that burns up energy at a massive rate is a frog attracting its mate by calling. A good set of calls gives frogs a better chance of getting a mate, so they have to go way beyond the occasional weak croak.

  Calling is so important in one particular frog species that they compress their whole chest to force a massive blast of air through their vocal cords. These chest muscles are huge—20% of a frog’s total weight. And the muscles are special as well. They are packed with blood vessels and mitochondria, so that they can keep on contracting powerfully for a long time. When these frogs call for their mate, they are burning up energy at 20 times their resting BMR.

  As far as staying power is concerned, these frogs are between human beings and pythons. They can keep calling three times a second for seven hours.

  Kings of BMR Rock (Gutwise)

  Pythons live on a razor-thin edge between too much food and starvation, so they spend most of their time waiting. They have to wait. Mathematically inclined biologists have worked out the sad statistics for a python that might cruise around looking for food. They calculated that the extra food that the snake found would not compensate for the extra energy that it would have to burn up in hunting the food. In other words, a python that cruises around hunting for food would starve to death. For this reason the python has adapted a lifestyle of sitting and waiting for weeks, and sometimes months, without eating a meal.

  Pythons can really throttle back how much energy they use. When your standard python is not eating and just living off its energy stores, it will shrink its gut to stop the normal flow of digestive juices. After all, it takes lots of energy to make these juices. The python will also shrink its liver, kidney and even its heart, as starvation stares it in the face. So the python will stay completely still for days, weeks and sometimes up to six months waiting for dinner to come within range. And, of course, once our python swallows a few rats, its liver, heart and kidney will amazingly swell by up to 50% within a day or so.

  Save Energy by Being Blind

  Scientists have found incredible economies of energy in the animal kingdom. For example, Brian McNab, a biologist from the University of Florida, has been studying the Texas Blind Salamander. He thinks that he might have worked out why it is blind. The Texas Blind Salamander lives in underground caves where there is no light, and where the food supply is just small random scraps carried through by underground streams. Any animal that survives down there will have to conserve all its energy. And it turns out that in the eye, the retina and cornea burn up a huge amount of energy, the cells always being replaced by new cells.

  At some stage in the past, there was almost certainly a random mutation which resulted in a blind salamander. Because there’s no light in these caves anyway, the first blind salamander wouldn’t have been at a disadvantage. In fact, being blind would have saved energy. Presumably, this mutation gradually multiplied over the generations until, eventually, all the salamanders in this cave were blind.

  Back to Food Tax—The Wrap-up

  In pythons, the ‘Energy Tax/Thermic Effect’ can reach about 30%—so the snake gets only 70% of the energy in the meal.

  In human beings, the Thermic Effect is much less, perhaps because metabolic processes can be more efficient if they are regular (e.g. three meals per day). Interestingly, the energy needed to process a meal varies with the type of food consumed. This Energy Tax is about 25% for proteins; 2–3% for fats; and about 5–10% for average carbohydrates. So if you ate 100 kJ of each, after digestion you’d be left with 75 kJ from the protein, 97–98 kJ from the fat and 90–95 kJ from the carbohydrates. In general, nutritionists calculate that a reasonable Energy Tax for the average person’s diet is about 10%.

  But note that the Energy Tax is never greater than 100%, which is what the ‘celery negative kilojoule’ myth claims.

  The Energy Tax on fat is God’s little joke. Not only does fat have the highest number of kilojoules per gram of any food, it also has the lowest Energy Tax. This guarantees that eating fat will really stack on the blubber. Surprisingly, the Atkins diet (high fat, high protein and low carbohydrate) helps people lose weight—but only for a short time. This is because protein is the most ‘filling’ of all nutrients. Second, foods such as chocolate and ice cream are forbidden because they contain carbohydrates. But people can’t stand this diet for more than a few months. This is probably good because a long-term diet of lots of protein would overload the kidneys.

  Celery—The Bottom Line

  Nibbling on a stick of celery is nothing like chewing on a chunk of cow. Celery is about 95% water, 2.2% digestible carbohydrates, 1.8% indigestible carbohydrates, as well as insignificant amounts of protein and fat. The digestible carbohydrates in 100 g of celery will provide you with 32 kJ, while the indigestible carbohydrates will give you 16 kJ (because bacteria in your bowel ferment them to make energy). And the energy needed to process all of these carbohydrates will be about 4 kJ, leaving you with about 44 kJ—a small number, but definitely not a negative number. So you do get a few kilojoules from eating celery.

  One thing is certain, however—if your mouth is full of celery, there’s no room to stuff in fatty, high-kilojoule foods like chips and hamburgers.

  Is there a food that takes more energy to digest than there is energy in the food? Probably ice. You definitely burn up energy when you heat the ice into liquid water, and I am pretty sure that t
here are zero kilojoules in water. Black coffee, tea and diet cola also have no kilojoules—but they do contain caffeine, which will rev up your BMR by about 10%. However there is no research to show that caffeine addicts are any thinner than the rest of us…

  Less Than Zero?

  In the USA, various companies are now marketing drinks that they claim can help you lose weight. This is very interesting, considering that a study presented at Experimental Biology’s 2005 annual meeting found that soft drinks account for 9% of calories in the average American’s diet. (A decade earlier, white bread was the culprit.)

  How can drinks make you lose weight? By including stimulants that increase your BMR. Currently, flavour of the month is epigallocatechin gallate, an antioxidant found in green tea and caffeine.

  It all sounds boringly familiar. Heroin was introduced to combat addiction to morphine, valium was the ‘perfectly safe’ drug to help you sleep, and amphetamines would help you lose weight. Have these companies never heard of ‘side effects’? Better Living Through Chemistry is not always the way.

  Fibre and Carbohydrates—Confusing Definitions

  ‘Fibre’ is a confusing term, when it refers to food that you eat. Fibre, according to nutritionists, is definitely not bamboo stalks or the stuffing inside old mattresses. It’s an old term, used to refer to ‘indigestible carbohydrates’, which are in reality partly digestible. (Sorry about that—life can be confusing.)