Pounds of flesh

In kindly sponsoring my effort in the Noosa Triathlon, where I’m supporting HeartKids (click on the button at the right to help) long-time commenter Jack Strocchi made a demand for a “pound of flesh” in return. Sad to say, I’m going to shortchange him. Based on past performance I expect to burn about 2500 calories (or about 10 Megajoules, just to make life hard for some of the computationally-challenged media figures we’ve been poking fun at lately). That corresponds to about 10 ounces (300g) of fat, most of which will be replaced in advance with a big pasta meal the night before the race. Of course, if I allow fluid loss, and weigh in just after the race, it will be more like 2kg.

One of the side benefits of taking up exercise is that I can now do all sorts of conversions of this kind. For example, a glass of red wine is about 150 calories (600 kJ)[1], and running uses about 75cals/km[2] so I have to run 2k to burn it, which seems like a fair deal. By contrast, despite their healthy image, a typical muffin is about 450cal/6km, definitely not worth it to me.

Perhaps I’m a bit too obsessed with numbers. But on matters of this kind, I’m with Lord Kelvin who observed

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.

Update A fun theoretical observation that just came to me, and which I don’t remember seeing anywhere else. It’s obvious and well known that, the heavier you are, the more energy you need just to move yourself about. In fact, a 50 per cent increase in body weight implies a 25 per cent increase in the energy intake needed to sustain a given level of activity (try this calculator). What this means is that there is a linearly increasing relationship between body weight and the energy intake consistent with maintaining that weight. Turning that around, any given energy intake is consistent with a unique stable weight, for given activity level. So, whatever your starting point, if you eat the amount consistent with your target weight, and change nothing else, you will end up there, sooner or later.

fn1. A "standard drink" is more like 100, but that's a small glass. If you are keeping count for driving purposes, two drinks of any kind usually amount to three standard drinks.

fn2. Surprisingly, so does walking. Energy consumption is determined mainly by distance travelled and body mass – the speed at which you go affects the rate of energy use, but not (much) the total over a given distance.

19 thoughts on “Pounds of flesh

  1. “Energy consumption is determined mainly by distance travelled and body mass ā€“ the speed at which you go affects the rate of energy use, but not (much) the total over a given distance.”

    I thought, based on nothing more scientific than something I once read somewhere by someone, that the benefit running offered over walking in terms of weight loss was that running was, mechanically speaking, considerably less efficient, so it took much more energy to move your body over a given distance.

    Very happy to be corrected.

  2. Pretty sure that in my case at least it’s running (at a moderate pace, let’s say “cantering”) that’s more efficient than walking (certainly than walking fast). I don’t have calorie counts for you sorry. I know that if I become a bit fatigued while walking somewhere my inclination has always been to run more, walk less. Born to run perhaps but I think it might apply to others as well, and I could rationalise it by analogy to things such as auto engines that operate at peak efficiency when somewhere above their idling or “walking” rev ranges.

    If your aim is to burn calories so as to lose weight, and if you don’t physically love the sensation of running, then you should opt for a walk over the same distance. You’ll lose at least as much weight but enjoy the exercise more and do less damage to your joints.

  3. Just to be even more obsessed about numbers and units of measurement: you should be using the symbol Ca which is, in nutrition, the traditional unit of measurement, also known as the large calorie or kilocalorie. The small calorie (symbol ca) is (was for us metric countrties) used in other fields as a standard measurement of energy. 1 Ca = 1000 ca.

  4. @doug I sort of knew this, but I plan to convert to kJ anyway, so I’ve never bothered getting it straight. Silly US Runkeeper app won’t allow kJ, despite many requests.

  5. My guess is that running is more mechanically efficient, but that the respiratory engine is less efficient at the required rate of use, and these effects roughly cancel out

  6. An Iphone app I once used allowed me to enter food eaten and exercise taken. As far as I can tell from the numbers it generated, it estimated about 19Ca/minute for steady running (I think it was 8mph) compared with 4Ca/min for walking at 3mph – both on flat terrain. Skipping was about 14Ca/min. UK app so imperial measures. If you’re time poor but have good knees, running seems to be a better way than walking to offset the red wine.

  7. Excercise is one possible way to burn fat. The other way to burn fat is to increase your metabolic rate. Your metabolic rate can be increased with changes in diet (hence Atkins and Paleolithic diets) and/or by increasing muscle mass (via weight lifting). Simply having more muscle tissue means burning more calories even when you’re asleep or reading a book. It’s almost like cheating.

    I spent several years trying to lose fat by swimming and running but I struggled and mostly went backwards. Then last year I switched to a strategy of boosting my metabolism and lost 17kg in 17 weeks.

    What I did involved a lot of time spent in the gym but none of it was cardio exercise. In other words there was no running, swimming, dancing, treadmills or the like but lots of lifting, squatting etc. I did sweat but I never puffed.

    I also radically changed my diet. I eat steak, sausages or eggs for breakfast and abolished cereal. Previously I had fanatically eaten raw oats for breakfast for years but now I try to avoid carbs (cereal, bread, potatoes, pasta) entirely during the working week and keep to a minimum on weekends. However I still eat lots of food, probably more than I used to.

    The muffins isn’t for me but not simply because of calories. A decent steak, like I just had for lunch, has many more calories but I won’t be doing any running.

  8. That’s pretty impressive weight loss Terje! I’ve lost about 10kg over 2 years by calorie counting and tracking my weight (adopted the ‘Hackers Diet’ approach) rather than altering my diet and metabolic rate.

    Have you noticed any other effects? I’ve had problems with cholersterol which is an important factor behind my reluctance to adopt a high protein diet

  9. Regarding carbo loading, I have observed in recent articles, that some of the Tour de France teams, who have large budgets and specialist nutritionists, and burn more kj than most, have changed from pasta to vegetables for their carbs.

  10. Adam – no noted side effects other than feeling great. That said I have not had a cholesterol test in the last 12 months.

  11. Any diet/exercise combination will work for healthily losing weight provided;

    (a) it still contains all essential nutrients in a balanced manner;
    (b) it does not introduce excess quantities of deleterious factors (salts, fats, sugars etc.); and
    (c) calorie intake is less than calorie output.

    I have tried a “no fats” diet and a “one meal a day” diet. They both worked essentially because they both meant giving up junk food (cakes, biscuits, chips, salted nuts and take-away food).

    Currently I am fat again (85 kg when I should be 75 kg). I find I can diet and exercise for about 6 to 9 months (losing up to 10 kg in the process) and then I lose discipline and put it all back on again in about the same time span. Any suggestions to prevent this backsliding? I am the shopper and cook for my family and I find being forced to be around tempting food so often is the problem. It’s relatively easy to avoide excess food until you have to cook big hearty meals for teenagers and stock the pantry with extras to stop these rake-thin teenagers (who eat an enormous amount of food) from complaining “I’m starving”.

    If I only had to shop and prepare food for myself I think I could keep to a sparse pantry and a low fat diet considerably more easily.

  12. John,

    Not that I want to defend the muffin, but the glass of wine will also place a load on your liver function, which will slow your metabolism and so result in a lot more of it being converted into fat. (Though I guess the sugar in the muffin will probably cause an insulin spike with its own effects on fat conversion). Still, the calculation is not as obvious. šŸ™‚

  13. Terje: thanks for the feedback
    Ikonoclast: I have suffered from a similar problem, with self-control the challenge – I even ask my wife to ‘hide’ the snacky foods in the pantry to avoid them. There was an interesting article in the Atlantic Magazine there was an interesting article on behaviour modification and sustained weight loss – it might give you some ideas.

  14. @Adam M

    Yes, will-power, or won’t-power as some jokers call it, is a tricky thing. But certainly, it is easier to avoid hunger pangs, mouth salivations and consequent snacking by actually avoiding the various stimuli that provoke appetite. For a well fed person, sight and aroma of food are the main culprits with aroma being the most potent. For a hungry person, you can add in the empty stomach feeling. As I said, it is hard to avoid the stimuli that provoke eating and over-eating when you are constrained to be the purchaser and cook for a household (with fit, active teenagers) that demands and indeed needs a relatively high calorie diet.

    I did have my best success with a one-meal-a-day diet. Eventually, after 6 months or so, I could not keep to it due to social and familial pressures. I had everyone from the family to the family doctor telling me it was not healthy to only eat one meal a day. What I did was eat a normal evening meal at 6:30 pm, a piece of fruit and then a high fibre breakfast cereal with skim milk at 7:30 pm (instead of dessert). Next morning I would have half a glass of orange juice and then through the daylight hours (approx 12 hours) I would live on black, unsweetened tea and a few glasses of water. Between about to 4 pm to 5 pm I would walk briskly for about 50 minutes.

    Black tea and lack of food through the day seem to have a shrinking effect on the stomach so that one soon feels full with the single evening meal. Hunger pangs and eating are thus controlled and snacking eliminated. However, the key would be to commit to such a regimen for life. When one is forced to lunch, for social reasons, then the lunch becomes the sole meal and the evening meal is skipped.

    I disagree with medical advice that this diet is not healthy, at least in my case. I seem to have a metabolism where my body can “run” quite happily on one meal a day if it is forced to. No doubt, this would not be true for all people especially those with diabetes, coeliac disease etc etc. Exercising after an 18 hour “fast” probably forces the body to mobilise and burn fats to replace the glycogen stores burnt during the actual exercise. I suspect that primitive man and woman (early hunter-gatherers) often ate in this fashion with a few left over berries or suchlike forming breakfast, water from local creeks during the day and a communal “feast” of hunted and gathered foods at twilight.

    It seems to me that is it the “civilized” standard of three meals a day (often with morning and afternoon teas in between) that is artificial. We may in fact be more properly adapted to the one meal a day regimen.

  15. Ikonoclast – your assertion is true. Where I think it can be unhelpful though is in the detail obscured within point (c). Metabolism and exercise both burn calories but metabolism does in 24×7. For a busy fat person serious calorie burning exercise is a tough ask. And calorie restriction is psychologically very difficult.

  16. …when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind…

    How do I love thee? Let me count the ways….

    (whenever I hear of culture I reach for my Browning).

  17. There are many reasons I love this blog, but most of them have been posted in this thread, some from unexpected sources. Here’s my 2c. I have lost 8 kg in about 3 months in a Terje-like process. However, my fat content has moved from about 22% to about 14%, meaning that I have gained muscle mass and lost more fat than my weight loss would show. In agreement with mine host, give me wine over muffins any day, although one needs to be aware that they actually metabolise differently.

    And finally, may I recommend the sport of “crossfit” to Prof Q. “Why suck at one sport when you can suck at three?” is a good option, but sucking at 27 or so must therefore be so much better. More seriously, the fact that you even ran 37 KM, no matter how long it took, is a matter for celebration. I look forward to your marathon time – you look after your knees.

  18. And, the answer to which is more efficient is ………….. walking, hands down.

    Table B: Your Calorie Burn Per Mile Walk vs Run
    .57 x wt in lbs .72 x wt in lbs

    your weight (in pounds) by the number shown. For example, if you weigh 188 lbs, you will burn about 107 calories (188 * .57) when you walk a mile, and about 135 calories (188 * .72) when you run a mile. (Plus afterburn)

    Then add 190 calories of afterburn. (For what it’s worth, I tend to think that the afterburn for marathon or triathlon, a really extended amount of exercise, is much higher. I remember the energy required to synthesize breast milk for instance from years ago. Chemical synthesis of proteins is quite expensive, and the amount necessary after a marathon has to be much higher.)

    So let’s say John weighs 80 kg. That makes him approx. 176 pounds. Multiply by 0.72 kcal per mile is 126.72 kcal per mile. 37 km is 22 miles and change, call it 22. That’s 2787 kcal for the run. Add in afterburn over 24 hours and it’s 2978. Since this is a long run I’d put the afterburn at 3 times that 190, so my estimate for total kcal consumed is 3358. If someone wants to be purist, they can use the 2978.

    That said, if John wants to raise his calorie burn per day when he’s not running, he could add muscle mass. This would raise the amount of mass he moves when he runs. It should also mildly increase his resting metabolic rate. One kilogram of muscle has an RMR of 13.2 kcal per day, and one kg of fat is 4.4 kcal per day RMR. But, the real world effect of increasing muscle mass is larger, because when a person is stronger they are more likely to use that muscle tissue. So your muscles won’t use 13.2 kcal per day, they will consume more kcal, and fat doesn’t rise above RMR. In the real world a gain of 5 kg of muscle (which is a lot) is probably worth 80 kcal per day. Over the course of a month, that’s like running an extra 25 km.

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