In our last lecture, we presented two models for visualization of the concept of energy
consumed and energy expended as strongly linked together. Each model requires estimating the amount
of energy consumed and the amount of energy expended [I recommend the easy way, by allowing
software, such as DietAnalysis+ or MyPyramid, to do the estimating for you]. After entering the
data into the model of your choice, you can assess the probable weight dynamics
(increasing, stable, decreasing) for yourself, based on the linkage of intake and output.
We spent the rest of the lecture examining strategies for managing the energy
consumed side of the ledger. The strong recommendation was to avoid fad diets and organized weight
loss programs, and instead control energy consumed by controlling portion sizes for energy supplying
food, while maintaining variety in the diet to assure that no nutrients would become deficient.
We shall now examine various strategies for managing the energy expenditure side of the ledger.
We can classify [being scientists, “we can” is usually translated into “we
should,” and in English means, “we intend to”] Human energy expenditures into the
following 5 groups:
1. basal metabolism (BMR),
2. nonexercise activity, including Activities of Daily Living (ADLs),
3. thermic effect of food (thermogenesis),
4. [intentional] physical activity, and
5. Savings (or contributions to the adipose).
Basal metabolism (BMR) is the amount of energy you use while “doing nothing;” BMR
tends to remain fairly constant over long periods of time (except after large changes in
intentional
activity levels). Non-exercise activity includes ADLs, and does not count as exercise. The thermic
effects of food are the Calories consumed in chewing, swallowing, digesting food to nutrients,
absorbing nutrients, and voiding undigested remains of food. The more I work with estimating Calorie
requirements of sedentary people, the more convinced I am that the thermic effects of food should be
included in BMR. It is only when the Humans go on their hunting and gathering expeditions that they
spend energy beyond BMR, but these hunting and gathering activities are ADLs, and don't count as
exercise [no matter how many steps your pedometer says you took hunting and gathering at your local
friendly supermarket, or favorite fast food restrauant drive-up window where you took exactly zero
steps]. Exercise is any physical activity you didn't have to do, but chose to do anyway. Exercise is
the only energy expenditure that you can control as part of a weight management program. After
accounting for all the above energy expenditures, any [and all] surplus is deposited in your savings
account at the First National Bank of Adipose-Tissue [FAT]. It is no easier to get energy out of
this account than it is to cash out your retirement plan (if you have one, such as an IRA, 403-b, or
401-k), and cashing it out is very hard to do until you are at least 55 years old and facing a
financial “emergency.”
While preparing for in-class lectures over several semesters, I developed a model to describe the
mechanisms Humans evolved to process energy, especially when the energy consumed is either
excessive or deficient. Such mechanisms were, at one time in our evolutionary history, critical to
our survival as the food supply alternated between plentiful (during the growing season) and very
scarce (during winters). The ability to store excess energy, and later retrieve it, became
increasingly important to us [and other omnivores (creatures capable of eating just about anything
that doesn't eat them first) like Bears] as the Ice Age became more severe year after year. Clearly,
we had some survival mechanisms to get through the Pleistocene Ice age, because the last time I
checked there still seemed to be at least a few living specimens of Humans on this planet. What we
did not have during the Ice Age was a calendar to tell us when the growing season was about to end,
so it came as a big surprise every year. The concept of predictable seasons has been with us for
only a few to several millennia.
Humans, as a new species (Homo sapiens), had to have a purely physiological
mechanism to store excess energy (as the opportunity arises), and later retrieve it (as the need
arises). You already know [from the “Energy” lecture, subheading “Physiology”]
that the liver:
1. intercepts excess sugar from the blood stream;
2. converts the glucose sugar to glycogen, using insulin [from the pancreas];
3. stores the glycogen in the liver;
4. when blood sugar drops too low, converts glycogen to glucose, using glucagon [from
the pancreas]; and
5. dumps the glucose back into the blood stream.
This well known process is able to manage blood glucose over periods of minutes to hours.
Adding a few refinements to this process may provide management of energy storage over periods of
months to years, and unfortunately for currently living Americans, even decades. The following is
my hypothesis for how the physiology of long term energy storage works to allow long term Energy
Storage, and Energy Retrieval [including annoyingly detailed Physiology].
The liver is known to intercept excess glucose from the blood stream (hepatic portal vessel) for
temporary storage either as glucose [very limited] or as glycogen (“animal starch”) in the
liver. Glucose can be stored for hours; while Glycogen can be stored in the liver (and muscle tissue)
for days, providing a good intermediate term storage of energy. The synthesis of glycogen from glucose
involves insulin. The retrieval of energy stored as glycogen requires that the glycogen be digested
back to glucose which involves another pancreatic enzyme, glucagon. The insulin - glucagon mediated
intermediate term energy storage system is considerably more complicated
than this ‘simple’ explanation, but the simplified version will suffice for the purposes
of a Nutrition course. However, the liver and muscle tissues have a limited capacity to store
glycogen, although it is greater than the capacity for glucose storage. And storage over a period
of days is insufficient to get us through a Pleistocene winter without grocery stores [worse even
than the winters of 1978-79, 1983-84, and perhaps 2008-09 in the Lake Michigan snow belt (Indiana);
actually the winters of 16th to 18th (or 19th) Centuries were much
worse, during the period known as “Little Ice Age.” The (Global) cooling began as early
as A.D. 1250 and (Global) warming didn't begin until around A.D. 1850 and has continued to today
(dates from www.windows.ucar.edu/tour/link=/earth/climate/little_ice_age.html)
[this warming event should continue to about 2400 - 2500, with or without Human schemes to reverse
the trend]. The year 1850 is also the approximate date of the Industrial Revolution, and the start
of the presumed “Human-caused” global warming (according to Al Gore, who is neither a
climatologist nor an atmospheric scientist) which ignores the 40+ year long hot, dry period ending
1300 A.D. at the end of a global warming event which began around A.D. 600, not to mention the more
severe (compared to the 1850 to 2009… event) global warming event of 220 million year B.P.
(before present), when our species wasn't even here].
When the capacity of the liver to store glycogen is exceeded, a longer term
storage option is needed to store the surplus energy. The mechanism for this is the conversion of
glycogen to fatty acids, then to fat which can be stored in the liver. If the liver were to
continue to add fat storage in itself, the resulting condition is called cirrosis which can
become fatal. The liver can avoid cirrosis by converting excess fat back to fatty acids for transport
via the blood stream to alternate fat storage tissues (adipose tissue). Adipose storage of energy as
fat occurs initially in sex-specific locations, but can spread into the abdomenal (the gut) and
thoracic (chest) cavities [where it becomes a serious medical issue]. Fat can be stored in adipose
tissues indefinitely… months to a life-time (where the lifetime can be shortened by the presence
of too much stored fat).
When blood glucose (at the hepatic portal vessel) drops, the liver returns some of the stored
glucose to the blood stream, which reduces the amount of stored glucose. A secondary source of
glucose for return to the circulating blood is from glycogen storage. This requires digestion of
glycogen to glucose, with glucagon to activate the appropriate enzymes. This glycogen to glucose
digestion can also provide glucose to replace the stored glucose. This, in turn, reduces the amount
of stored glycogen. The glycogen can be replaced by converting fat from the liver to fatty acids,
then back to glycogen (also stimulated by glucagon). Typically, liver stored fat is replaced only
from dietary fats and from surplus blood glucose.
When the liver cannot replace the stored glycogen from fat stored in the
liver, the liver will initiate mobilization of adipose fat. The adipose tissue will then digest fat
back to fatty acids and return the fatty acids to the blood stream for transport. The liver can then
take the fatty acids from the blood stream and use them to synthesize more glycogen. Clearly, this
hypothesis requires that the liver somehow communicates to the adipose tissue, to initiate fat
deposition in the adipose tissue, and to initiate mobilization of adipose-stored fat to meet current
energy needs. In 2007, it was reported in Science, the journal of the American Association
for the Advancement of Science (AAAS, pronounced triple-A, S), that researchers have discovered that
the liver does exactly this by communicating to the brain stem via the vagus nerve the message to
start fat deposition, or the message to start mobilizing fat. This message has two effects: the
message is relayed via the sympathetic nerve system directly to the adipose, and the hypothalamus
stimulates the production of appropriate hormonal signals (to the adipose) either to store more, or
to mobilize the existing stores of, fat. The hormones cause the deposition or mobilization of fat to
continue for some time after the nerve signal to start. In summary, it is relatively easy to get
more fat stored -simply consume too many Calories in your diet; but far less easy to get the fat
mobilized to be used as an energy source -the liver will try all other options before tapping
into the only long term energy storage system it has. The liver has obviously seen the Weather
Channel show, It Could Happen Tomorrow, and wants to maintain the long term energy storage in
case the Pleistocene returns tomorrow.
Since a temporary decline in Calorie intake actually triggers fat deposition,
and since the liver is programmed to manage energy resources by maintaining an energy reserve in
long term storage, ‘dieting’ is unlikely to be effecive in reduction of body weight for the
over-weight population. This leaves only the other side of the ledger, the energy expended.
In fact, the body can be “tricked” into mobilizing body fat as an energy source by
increasing energy expended, by increasing what Roizen & Oz call “intentional activity.”
Exercise is, at its simplest, any activity that you didn't have to do,
but did anyway. The best advice from MD's knowledgable in weight management for wellness is to hide
the bathroom scale, and use a tape measure to monitor shape, specifically: chest, waist and hips.
Most, and perhaps all, over-weight people will need to reduce calorie intake by using portion
control to limit calorie intake, while using a variety of foods to assure broad nutrient intake
guidelines are met. Unfortunately, the most critical change in the over-weight person's behavior
will be to increase energy output by increased “intentional activity.” It remains important
to recognize that slow weight loss is healthier than rapid weight loss, and that most rapid weight
loss results in eventually regaining at least as much weight as was lost [often more weight is
regained than was initially lost].
It seems counter-intuitive that if you need to lose weight, you should stop
watching your weight. However, the typical bathroom scale does not do a very good job of estimating
weight for several reasons. The instrument is not very precise, where “precise” is the
statistical term for “repeatability,” or if you step on and off the scale five times, you
may get as many as five different weights. Based on data collected by my students [one example was
quoted in the previous lecture (“Weight Management 1”); this example is typical of the tens
of data sets analyzed], weight fluctuates by about a half pound daily when weight is [statistically]
stable, in part due to hydration status [remember about 90 lbs of a 148 lb Human is water], so it is
difficult to interpret whether or not any detected change is real. But, most importantly, total body
weight is a lousy predictor of weight-related wellness issues; the critical weight is the weight of
internal [as opposed to sub-cutaneous (just under the skin)] fat, which normal bathroom scales can
not measure. The newer scales which also estimate body fat percent do a better job of estimating
internal fat [and are only slightly more expensive as good spring-type scales], but at relatively
low precision and with very high sensitivity to hydration (which explains the low precision). Daily
measured fluctuations in body fat percent [again on a patient with statistically stable body fat
percentage] are about 5% of the 20-day sliding average body fat percent. Finally, it has been
reported [correctly] that patients on properly designed weight management programs often lose up to
two dress sizes [for males, size of slacks] while gaining up to 15 lbs. This occurs because
muscle mass is more dense (lbs per cubic inches of body) than is adipose; so the smaller dress size
reported involved a loss of fat (cubic inches) and a gain of muscle (gain in pounds). The patients
in the study were frustrated by their failure to lose pounds, until it was pointed out to them that
their dress size had gone down. And, I would point out, this weight gain is healthy,
because it contributes to an increase in BMR and to wellness (improving the expected quality of
your life as a geezer).
The key element of the weight loss program above that produced a gain in
weight and a reduction in size is that it was a “properly designed” weight
management program, combining reduced portion sizes of high energy density foods and
increased exercise.
For now, exercise comes in only two categories: aerobic and anaerobic [in our next lecture
(“Fitness & Sports”), we will look at fitness training and sports, where we will need a
more detailed listing of types of exercise].
Aerobic means “with oxygen,” or any exercise where the
heart can supply oxygen at least as fast as the muscles are consuming it;
Anaerobic means “without oxygen,” or any exercise in
which the muscles are demanding oxygen faster than the heart can supply it.
Hopefully you have anticipated that this implies that exercise may put some stress on the
heart, so you have an uneasy feeling that you ought not to be doing too much exercise. If you
were thinking that, then you were absolutely correct [I prefer to think that you were in fact
thinking exactly that]. Prior to beginning exercise, you must know how much exercise you can
realistically tolerate without triggering the heart attack for which excess weight is one of the
several risk factors among over-weight patients. I would recommend first checking with your doctor to
determine if a stress test (or other assessment) will be needed to determine the intensity of
exercise you can tolerate. He/she should want to know what kinds of exercise you are considering, so
tell him/her. Heart attacks may drive weight loss, but are not the best treatment option for
over-weight patients.
During aerobic exercise, the heart is able to keep up with the increased oxygen demand by the
muscles. This should mean that the heart can also supply most of the increased glucose demand as
well. Although the muscles will consume some of their store of gylcogen, the heart will supply
sufficient glycogen from the liver to replace that used in the muscles. As a result, although
energy expended increases, the result will be to reduce the rate at which fat is deposited into
the adipose [i.e., limit further weight gain], but it may do little to reduce the total adipose
storage of fats [i.e., lose weight]. On the other hand, one of the muscles being exercised is the
heart, so cardiovascular (and respiratory) health will be improved [the minimum time frame for the
beneficial cardiovascular/respiratory health is weeks]. If the
aerobic exercise continues, at least two days a week for a few months or more, resting metabolic
rate may accelerate slightly. After about three months of regular aerobic exercise, the muscle cells
appear to develop more mitachondria [up to double the number in the sedentary muscles], and it is
probably the number of mitachondria you own that establishes the resting metabolic rate.
“Dance aerobics” sometimes produces “weight loss” by
mis-representing the weight loss. Some dance aerobics classes for weight loss put the scales on the
gym floor rather than in the locker room. The clients change into their suitably fashionable
Danskins™ in the locker room, then go out to the gym floor to weigh in. After the session, they
weigh out on their way to the locker room; showing a weight loss of 4 to 7 pounds (2 - 3 kilos).
However, the particpants are thirsy and drink a coupla pounds of water, then shower and change back
into their What Not To Wear street clothes. On the way out of the building, they pass by the
vending machines where they buy diet cola (they are still thirsty), and, of course, Snickers™
really satisfies, so they buy a candy bar too. By the time they get back home they may have gained
back a pound more than they “lost.” The mis-representation is that the “weight
loss” was 100% (salty) water, lost as sweat. The participants did not notice that they were
sweating because the air conditioner was running as a dehumidifier, so sweat immediately evaporated
[and women, even at dance aerobics class, “don't sweat”]. Four to seven pounds of water
lost as sweat is not unlikely, because athletes can lose up to 22 lbs (10 kilos) of water as sweat in
a single athletic event.
For the over-weight, sedentary person, aerobic exercise for two weeks to two
months is an excellent way to get started, because of the beneficial effects on cardiovascular and
respiratory health. It does, however, take a minimum of two weeks to see any appreciable
cardiovascular/respiratory benefits. For the sedentary population, it may take several two week
periods of cardiovascular workouts to raise cardiovascular health enough to be able to tolerate the
more strenuous exercise needed for weight management [longer for smokers]. You should know that the
simplest test of whether or not you are still in aerobic exercise is that you will be able to speak
in full sentences without catching your breath. For most of the over-weight population, two months
of strictly aerobic exercise is necessary to raise their cardiovascular health to minimal levels
needed to begin the weight management exercise they need. Walking with a friend (or spouse) with
whom you can chat while exercising is an excellent way to build your cardiovascular health. Since
most Americans normally walk at about 2 to 3 miles per hour, it is unlikely that they will
over-stress themselves in a 10 to 30 minute walk, while chatting (unless their stress test says
otherwise!). You should walk only half-way to ‘tired’ before turning around to return
home, so you can expect to get home today. Your first exercise walk should not exceed 5 to 10
minutes out, so you can make the 7 to 12 minute return trip safely. [And you can be almost
certain that the return trip will be at a slower pace!] You may sleep better
after even the first short walk (unless you have sleep apnea). The other advantage of limiting
yourself to 5 minutes out (and 7 minutes back) is that you are more likely to repeat the experience
“tomorrow” [defined as the “next time you exercise”] knowing that
it will be only a 10 minute walk than if you try for a longer walk. After you have tried this
a few times, it's OK to gradually increase the time (and therefore distance) you go. Ideally, you
should aim for two days a week for your walk, with a 10 to 20 minute duration.
Once you have successfully improved your cardiovascular health, you can shift to phase two of the
weight management program. Phase 2 adds some anaerobic exercise to your routine. Anaerobic exercise
begins when the muscles' oxygen demand exceeds the ability of the heart to supply oxygen. You can
determine that you have reached anaerobic exercise because you will no longer be able to chat with a
friend; you will not be able to speak an entire sentence without pausing to catch your breath.
Physiologically, exercise becomes anaerobic when the muscles shift to anaerobic respiration, or
lactic acid fermentation. Since the heart can not deliver oxygen as fast as the muscles use it, it
is safe to assume that the heart cannot supply glucose as fast as the muscles can burn it either.
The muscles must now rely heavily on stored (in the muscle tissue) glycogen as an energy source. At
about 20 minutes of glycogen-fueled cellular respiration, you trigger mobilization of adipose fat to
replace the depletion of glycogen storage in the muscle; importantly, the liver is not
involved in this utilization of fat reserves. The actual conversion of fat to fatty acids to
glycogen will usually begin at a pace that just meets the glycogen demand by the muscles until the
exercise session ends, then increase its speed, and can continue for up to two hours after
exercise ends. Once fat mobilization has been triggered [about 20 minutes of anaerobic exercise]
adding more exercise has no additional effect. Forty minutes does not get you four hours of
fat mobilization, but only two hours. Twenty minutes of anaerobic exercise followed by a minimum two
hour break, then repeating twenty more minutes of anaerobic exercise may trigger another two hours
of fat mobilization (in some, but not all, people). The old rule [from the last decade of the
20th Century] that the patient must exercise for 30 minutes to an hour [it seemed like a
good idea at the time, based on the presumption that fat is directly converted to glycogen to supply
energy to the muscles (which is only half correct)] has been replaced by the new 21st
Century idea [based on actual research, from which we learned the part about fat mobilization
continuing for two hours after exercise] that 20 minutes in the morning, and 20 minutes in the
evening is more effective [faster fat loss] and less stressful [lower risk of heart attack]. The
evening session will also promote sounder sleep, while the increase in intentional activity will
increase hunger, increasing the likelihood that you will eat breakfast [another counter-intuitive
observation of Humans and weight is that persons who skip breakfast gain weight more easily than
persons who eat breakfast].
Only athletically active adolescents can safely go from resting to anaerobic
exercise [and they shouldn't do so]. Young children give the appearance of going from resting to
intense activity quickly, but (1) they probably remain aerobic for most such activity, and (2)
they don't really rest while they are “resting.” The rest of us will require stretching
and warm-up (or aerobic exercise of the same muscles as will be used for the anaerobic exercise) for
at least 5 minutes before beginning the 20 minute anaerobic exercise. The stretching is intended to
loosen up the joints which will be used during the exercise session, to minimize the risk of joint
injury; the ‘warm-up’ is primarily to gradually increase the pulse rate and blood volume
pumped to minimize the risk of heart injury. The exercise session is followed by another 5 minutes of
cool-down (aerobic exercise of the same muscles) to avoid cramping. As for phase one, the goal is
to get anaerobic exercise at least two days a week. It would be much better at 3 to 5 days a week,
but not over 7 days a week. [I warn my Nursing students that if they tell patients this, their
patients will probably drop out of the program before they drive past the McDonald's™ drive-thru
on their way home from talking to their Nurse]. If you can manage to get two 20 minute anaerobic
exercise sessions a day on 2 days per week, you are very likely to lose 2 inches off your waistline,
and may gain up to 5 pounds, six months to a year into the program. You should also enjoy an
increased life expectancy [age at death for 50% of a same aged population of individuals following
the same exercise regime] and statistically significant decline in probability of developing
non-Alzheimer's, age-related dementia. When living beyond say 98 years without dementia becomes
unacceptable, all you have to do is cease exercising, eat junk food, drink diet cola, and watch TV
[which according to an ad on TV for TV back in January of 2009, shrinks your brain to a small lump
of jelly-like substance], and you too can become demented and die.
This was not a professional driver on a closed course; you can attempt
this at home. However, should you try this at home, you will experience a cascade of physiological
effects. At first, the anaerobic cellular respiration (lactic acid fermentation) will produce the
mildly toxic lactic acid as a by-product. The purpose of the cool-down period is to maintain the
elevated pulse rate long enough to supply Oxygen to support synthesis of pyruvate from the lactic
acid [reverse fermentation], then aerobic respiration of the pyruvate to CO2 and
H2O, but the increased blood flow will transport some of the lactic acid out of the muscle
tissue. It was probably the lactic acid in the blood supply to the adipose that triggered fat
mobilization in the first place [as soon as the concentration of lactic acid in the blood reached
the necessary threshold at about 20 minutes of exercise; it varies from one individual to another].
When the hypothalamus detects lactic acid in the blood [at a higher concentration than the threshold
for fat mobilization], it triggers anabolic steroid production in the pituitary gland, and the
anabolic steroid drives growth of muscle tissue by stimulating muscle stem cell division. Each new
muscle cell produced will have more than one mitachondrion (and remember, exercise, even aerobic
exercise, stimulated the production of mitachondria in existing muscle cells}. The increase in
mitachondria causes an increase in resting metabolic rate. Idle muscle tissues requires about 75
kilocalories per pound per day, compared to the huge 3 kilocalories per pound per day for fat
tissue. [For those of you who don't do algebra on a empty stomach, idle muscle can use up to 25 times
as much energy than idle fat (and all fat is idle) can.]
The simplest anaerobic exercise is a brisk walk. Remember, the average
American walks at about 2 to 3 miles per hour (and we suggested walking as the cardiovascular
exercise above). Now we want the patient to step up the pace, with a target of 4 miles per hour
(15 minutes to walk one mile, or about 1,250 steps on your pedometer after a ten minute walk).
Jogging would be acceptable, but most people associate jogging with “serious” fitness
exercise [the kind done by fitness freaks], and jogging is not friendly to your knees. There
are numerous books available explaining “how to jog,” or “how to walk.”
Unfortunately, nearly all of these books are wrong; they recommend jogging or walking patterns which
will damage the knees. The popular books on jogging and walking all suggest that you should
land on your heel and roll up to the ball of the foot, then push off with your toes. This ignores
the anatomic design of the Human leg. Most opposing pairs of muscles, such as the quadriceps -
hamstring of the thigh (origin, or fixed end, on hip; insertion, or movable end, just above the
knee; the quadriceps straightens the knee, and the hamstring bends the knee) and the biceps -
triceps of the upper arm (origin just below the shoulder; insertion just below the elbow; the biceps
bends the elbow, and the triceps straightens the elbow), are similar in size. The big exception is the
tibialis anterior (shin muscle, which lifts the toe end of the foot) and gastrocnemius (calf muscle,
which lowers the toe end of the foot) pair. Why is the calf muscle so large compared to the shin
muscle [rhetorical question]? If you stand and hop straight up, then land on the balls of your feet,
as soon as the balls of the feet contact the ground, the calf muscle will contract (as a reflex) and
absorb most of the blow. If you hop again, but this time land on your heels, the blow will be
transmitted bone to bone to the weak link in the leg, the knee [and will also be tranmitted bone to
bone to the hip, back bone, and eventually the skull will bounce on top of the back bone, joustling
the brain inside the skull; remember: “foot bone connected to the ankle bone, ankle bone
connected to the shin bone, shin bone connected to the knee bone, knee bone connected to the leg
bone…”]. Rather than following the advice of the authors of books teaching you to walk/run
incorrectly, you need to practice walking correctly. As the leg swings forward, you should do a
plantar flex (in gymnastics, a “point”) so the ball of the foot and toes contact the ground
first (using the calf muscle as a shock absorber), then lower the heel [optional] down to the ground.
Now lift the heel, roll up to the toes and flex (bend downward) the toes to push off for the next
step. This awkward-looking method of walking is instinctive in Humans; just watch an infant learning
to walk - they walk on the balls of their feet until their parents sneak up behind them, place their
hands on the toddler's shoulders, and push the toddler down to get heel contact. The toddlers finally
re-learn to walk incorrectly. A side effect of walking correctly [digitigrade] rather than the
customary flat-footed walk [plantigrade] is that balance is improved sufficiently that ankle strains
and sprains are less likely even in shoes without ankle support. The theraputic effect is a 15%
increase in metabolic cost of walking digitigrade compared to plantigrade (from the abstract of a
paper presented at the 2009 annual meeting of the Society for Integrative and Comparative Biology:
Wednesday, Jan. 7 Plantigrade foot posture increases locomotor economy in walking but not in
running humans. CUNNINGHAM, C; SCHILLING, N; ANDERS, C; CARRIER, D*; Univ. of Utah, Salt Lake
City; Friedrich-Schiller-Univ. Jena; Univ. Hospital Jena; Univ. of Utah, Salt Lake City).
Basically this means that when the walk cost 200 Calories (according to the software), it
actually cost 230 calories when done digitigrade; so you can tell the software that you spent 1.15
times your estimated time walking to get it to estimate your calories expended correctly for
digitigrade walking.
As you may have anticipated, the behavior modification we are looking for in the patients is not the usual weight loss diet version (restrict calorie intake), but on the calorie expended side of the ledger or balance scale. We want the patient to alter their long term behavior to include intentional physical activity. We will examine the options for exercise as a means of improving wellness in the next lecture, under the sub-heading “Fitness exercise” [mostly to keep this lecture within a reasonable file size so it downloads quickly, even with a dial-up service].
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