confirmation - calories are impractical

Discussion in 'Food and nutrition' started by TC, Feb 27, 2006.

  1. TC

    TC Guest

    very interesting reading:

    http://www.animal-science.org/cgi/content/full/81/13_suppl_1/E27


    It is a long treatise so I'll leave it to you guys to read.


    But here are a few interesting excerpts:


    *******
    "The general equation ME = RE + HE has been recognized since the days
    of Von Liebig, but, for many years, the primary effort of energetics
    researchers was to describe and quantify the ME of food and heat
    produced (HE), with retained energy (RE) seemingly a secondary
    consideration. Lawes and Gilbert (1861) first employed the comparative
    slaughter method in experiments. Those experiments were of considerable

    interest because they demonstrated for the first time that
    carbohydrates were the major source of energy leading to the synthesis
    of fat."
    ****


    The term efficiency demands a numerator and a denominator along with
    terms and units of each. All have taken many forms when used to define
    "beef cattle energetic efficiencies" particularly when gross, partial,
    or net efficiencies are defined. The numerator is the caloric content
    of the product (megacalories of product) or its proxy, whereas the
    denominator is defined in units of diet (diet input). The units of diet

    can be weight, or megacalories or joules of GE, DE, TDN, ME, or NE.
    Additionally, the diet input can be divided into that provided for
    animal maintenance and that provided for product above maintenance;
    e.g., product/(total ME minus ME required for maintenance). Thus,
    enumerable ratios have, and are, being used to describe "energy
    efficiency of beef production." These efficiency ratios always embody
    three components:


    Diet energy cost of maintaining the animal per unit of time.


    Diet energy cost per unit of product.


    Rate of product per unit of time (product/fixed maintenance cost).


    However defined, the determination of partial efficiencies, e.g., body
    tissue energy gain/ME above maintenance, would appear to be a
    straightforward, simple process. But in practice, it becomes a complex
    problem with multiple levels of confounding, making it difficult, if
    not impossible, to precisely define the partial efficiency or
    maintenance energy requirement of the producing animal. A prime example

    of this complication is the frequently observed shifting maintenance
    requirements as animals adapt to changing levels of alimentation. For
    example, Marston (1948) reported a shifting of fasting heat production
    (FHP) of sheep in direct proportion to their prior plane of nutrition.
    Additional frequent confounders include changing diet digestibility,
    pattern of fermentation, microbial growth, and protein supply
    concomitant with changing levels of production or alimentation. Add to
    these the changing nutrient flux, metabolism, hormonal control, and
    product composition likely with changing level of alimentation and the
    simplicity of measuring or calculating "partial efficiency" becomes
    even murkier.
    *********


    Thermogenesis of individual human subjects associated with activities
    that are not purposeful exercise has been shown to be highly variable,
    heritable, and predictive of weight gain (Snitker et al., 2001) and low

    in obese individuals (Schoeller, 2001). Snitker also found that the
    measurement in respiration chambers of these "activities of daily
    living" correlates (r = 0.53) to individuals' free-living activity.
    These types of movements, sometimes called fidgeting, can elevate
    sitting or standing thermogenesis by 50 to 80% (Levine et al., 2000)
    and can be monitored in free-living individuals with inclinometers and
    accelerometers (Levine et al., 2001a). General usefulness of these
    monitors is apparently limited by the need to calibrate them to
    individual subjects (Levine et al., 2001b).
    *********


    A lot of the treatise talks about cattle, but a lot of the introductory

    stuff talks about the development of our understanding of energy
    efficiecies in animals in general which applies to the human animal.


    It seems to confirm a few of my points,


    1) "Those experiments were of considerable interest because they
    demonstrated for the first time that carbohydrates were the major
    source of energy leading to the synthesis of fat."


    2) "However defined, the determination of partial efficiencies, e.g.,
    body tissue energy gain/ME above maintenance, would appear to be a
    straightforward, simple process. But in practice, it becomes a complex
    problem with multiple levels of confounding, making it difficult, *if
    not impossible*, to precisely define the partial efficiency or
    maintenance energy requirement of the producing animal."


    3) "These types of movements, sometimes called fidgeting, can elevate
    sitting or standing thermogenesis by 50 to 80% (Levine et al., 2000)
    and can be monitored in free-living individuals with inclinometers and
    accelerometers (Levine et al., 2001a). General usefulness of these
    monitors is apparently limited by the need to calibrate them to
    individual subjects (Levine et al., 2001b). "


    So carbs have a major role to play in fat genesis and it is virtually
    impossible to apply calories to accurately predict weight gain or loss.



    TC
     
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  2. Max C.

    Max C. Guest

    Wow... this has been posted for hours and not one of the usual
    unscientific, obscenity-peppered replies have been made to it. Could
    it be that science is *finally* starting to prove too much for the many
    pseudo-scientific mindless zombies in this group?

    One can always hope.

    Max.
     
  3. TC

    TC Guest

    Max C. wrote:
    > Wow... this has been posted for hours and not one of the usual
    > unscientific, obscenity-peppered replies have been made to it. Could
    > it be that science is *finally* starting to prove too much for the many
    > pseudo-scientific mindless zombies in this group?
    >
    > One can always hope.
    >
    > Max.


    I'm hoping that people are reading what I post and putting some thought
    into what is being said as well as the ramifications. Instead of just
    knee-jerk-reacting to what they think I say or mean.

    Monitoring and counting calories is simply not a practical approach nor
    has it been an even remotely successful approach to predicting weight
    gain or loss in animals. Time to give up the ghost and stop beating the
    dead horse. Time to examine the alternatives.

    TC
     
  4. TC wrote:
    > Max C. wrote:
    > > Wow... this has been posted for hours and not one of the usual
    > > unscientific, obscenity-peppered replies have been made to it. Could
    > > it be that science is *finally* starting to prove too much for the many
    > > pseudo-scientific mindless zombies in this group?
    > >
    > > One can always hope.
    > >
    > > Max.

    >
    > I'm hoping that people are reading what I post and putting some thought
    > into what is being said as well as the ramifications. Instead of just
    > knee-jerk-reacting to what they think I say or mean.
    >
    > Monitoring and counting calories is simply not a practical approach nor
    > has it been an even remotely successful approach to predicting weight
    > gain or loss in animals. Time to give up the ghost and stop beating the
    > dead horse. Time to examine the alternatives.


    What in the hell are you babbling about now?

    Damn, if I know.

    Damn, if I care.

    Just thought that you might want to know.
     
  5. TC

    TC Guest

    Mr-Natural-Health wrote:
    > TC wrote:
    > > Max C. wrote:
    > > > Wow... this has been posted for hours and not one of the usual
    > > > unscientific, obscenity-peppered replies have been made to it. Could
    > > > it be that science is *finally* starting to prove too much for the many
    > > > pseudo-scientific mindless zombies in this group?
    > > >
    > > > One can always hope.
    > > >
    > > > Max.

    > >
    > > I'm hoping that people are reading what I post and putting some thought
    > > into what is being said as well as the ramifications. Instead of just
    > > knee-jerk-reacting to what they think I say or mean.
    > >
    > > Monitoring and counting calories is simply not a practical approach nor
    > > has it been an even remotely successful approach to predicting weight
    > > gain or loss in animals. Time to give up the ghost and stop beating the
    > > dead horse. Time to examine the alternatives.

    >
    > What in the hell are you babbling about now?
    >
    > Damn, if I know.


    Exactly.
     
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