Cookies help us deliver our services. By using our services, you agree to our use of cookies. More information

Body fat excess

From Bioblast
Revision as of 23:43, 3 January 2020 by Gnaiger Erich (talk | contribs)


high-resolution terminology - matching measurements at high-resolution


Body fat excess

Description

Body fat is conventionally expressed as BF%, which is the percentage of body fat mass relative to the total body mass. In the healthy reference population (HRP), there is no excess body fat, and the fraction of body fat in the HRP is expressed - by definition - relative to the reference body mass, M°, at any given height. Although M° is identical in females and males at any given height, the fraction of body fat is higher in females than males in the HRP.

Abbreviation: BF

Reference: BME

Body fat in the healthy reference population

If body fat is expressed as BF% = 100*mF/M (Gallagher et al 2000; Deurenberg et al 2001; Romero-Corral et al 2008; Bosy-Westphal et al 2009), then the body fat mass, mF [kg], is calculated from total body mass, M [kg],
mF = (BF%/100)*M                                           (Eq. 1)
Lean body mass, ML [kg], is the fat-free body mass, and is thus defined as ML M-mF,
M  ML + mF                          (Eq. 2)
In turn, M is the sum of the reference mass at a given height and excess body mass, ME M-M°,
M  M° + ME                                 (Eq. 3)
Excess body mass, ME, is due to accumulation of an excess fat mass, mFE, accompanied by a gain of excess lean mass, mLE, which includes increased bone mineral density, added bone mass and muscle mass due to the mechanical 'weight-lifting effect' (Iwaniec 2016 J Endocrinol). Thus Eq. 2 and 3 combined yield the definition for excess body mass,
ME  mLE + mFE                         (Eq. 4)
Inserting Eq. 4 into Eq. 3,
M = M° + mLE + mFE                           (Eq. 5)
The fat mass, mF, is defined as the sum of the reference fat mass and excess fat mass,
mF  m°F+mFE                           (Eq. 6)
Figure 1: Body fat mass, mF, normalized for reference body mass, M°, as a function of body mass excess, BME. Assuming a linear relationship of f(BME-1) (dashed lines), R2 is 0.969 and 0.985 for women and men, respectively. A logarithmic model (full lines) improves the fit slightly for both women and men (R2 = 0.979 and 0.988, respectively). The intercept at BME=1 is the relative body fat mass of the healthy reference population. For the two models, this is 0.24 to 0.27 for women and 0.13 to 0.15 for men. The linear slopes are not significantly different in women and men, at 0.59 and 0.54, respectively. The linear model, therefore, implies that an average fraction of 0.44 of the excess body mass is due to a gain of lean body mass, and a fraction of 0.66 is due to a gain of fat mass. Data were calculated from tabulated values in the original references, including European white populations, African Americans, Japanese and Asien Indian populations as indicated. The purported differences between Asian and non-Asien populations is based on BMI, ignoring the effect of height on BMI. In contrast, BME provides a unifying concept for ethnic groups of different evolutionary backgroud, with differences in body height as a key to normalize for appropriate reference body mass, M°. Althoug M° at any given height is identical in women and men, a well defined difference exists in the reference body fat fraction between women and men, independent of height and evolutionary background of the populations covered in the original publications.


Inserting Eq. 6 into Eq. 5 yields body mass as the sum of the reference mass minus reference fat mass (which is the reference lean mass, M°L = M-m°F), plus the total body fat mass and the excess lean mass,
M = M° - m°F + mF + mLE                 (Eq. 7.1)
M - M° = mF - m°F + mLE                 (Eq. 7.2)
Normalization for M° yields an expression related to the body mass excess, BME=M/M°
(M-M°)/M° = M/M°-1 = BME-1                                      (Eq. 8)
The excess lean mass normalized for M° is a function of BME (or BME-1),
mLE/M° = f(BME-1)                                           (Eq. 9)
Inserting Eq. 8 and 9 into Eq. 7.2 yields
BME-1 = mF/M° - m°F/M° + f(BME-1)                 (Eq. 10) 
Solving for the measured variable mF normalized for M°,
 mF/M° = (BME-1) - f(BME-1) + m°F/M°             (Eq. 11)
which finally shows the equation derived to plot the normalized body fat mass as a function of BME (or BME-1),
 mF/M° = (1-f)·(BME-1) + m°F/M°                 (Eq. 12)
In this plot (Fig. 1), the slope equals (1-f), and the intercept is the fat mass normalized for the reference mass at a given height in the HRP.


MitoPedia: BME

Questions.jpg


Click to expand or collaps

MitoPedia: BME

TermAbbreviationDescription
BME cutoff pointsBME cutoffObesity is defined as a disease associated with an excess of body fat with respect to a healthy reference condition. Cutoff points for body mass excess, BME cutoff points, define the critical values for underweight (-0.1 and -0.2), overweight (0.2), and various degrees of obesity (0.4, 0.6, 0.8, and above). BME cutoffs are calibrated by crossover-points of BME with established BMI cutoffs.
Body fat excessBFEIn the healthy reference population (HRP), there is zero body fat excess, BFE, and the fraction of excess body fat in the HRP is expressed - by definition - relative to the reference body mass, M°, at any given height. Importantly, body fat excess, BFE, and body mass excess, BME, are linearly related, which is not the case for the body mass index, BMI.
Body massm [kg]; M [kg·x-1]The body mass M is the mass (kilogram [kg]) of an individual (object) [x] and is expressed in units [kg/x]. Whereas the body weight changes as a function of gravitational force (you are weightless at zero gravity; your floating weight in water is different from your weight in air), your mass is independent of gravitational force, and it is the same in air and water.
Body mass excessBMEThe body mass excess, BME, is an index of obesity and as such BME is a lifestyle metric. The BME is a measure of the extent to which your actual body mass, M [kg/x], deviates from M° [kg/x], which is the reference body mass [kg] per individual [x] without excess body fat in the healthy reference population, HRP. A balanced BME is BME° = 0.0 with a band width of -0.1 towards underweight and +0.2 towards overweight. The BME is linearly related to the body fat excess.
Body mass indexBMIThe body mass index, BMI, is the ratio of body mass to height squared (BMI=M·H-2), recommended by the WHO as a general indicator of underweight (BMI<18.5 kg·m-2), overweight (BMI>25 kg·m-2) and obesity (BMI>30 kg·m-2). Keys et al (1972; see 2014) emphasized that 'the prime criterion must be the relative independence of the index from height'. It is exactly the dependence of the BMI on height - from children to adults, women to men, Caucasians to Asians -, which requires adjustments of BMI-cutoff points. This deficiency is resolved by the body mass excess relative to the healthy reference population.
ComorbidityComorbidities are common in obesogenic lifestyle-induced early aging. These are preventable, non-communicable diseases with strong associations to obesity. In many studies, cause and effect in the sequence of onset of comorbidities remain elusive. Chronic degenerative diseases are commonly obesity-induced. The search for the link between obesity and the etiology of diverse preventable diseases lead to the hypothesis, that mitochondrial dysfunction is the common mechanism, summarized in the term 'mitObesity'.
Healthy reference populationHRPA healthy reference population, HRP, establishes the baseline for the relation between body mass and height in healthy people of zero underweight or overweight, providing a reference for evaluation of deviations towards underweight or overweight and obesity. The WHO Child Growth Standards (WHO-CGS) on height and body mass refer to healthy girls and boys from Brazil, Ghana, India, Norway, Oman and the USA. The Committee on Biological Handbooks compiled data on height and body mass of healthy males from infancy to old age (USA), published before emergence of the fast-food and soft-drink epidemic. Four allometric phases are distinguished with distinct allometric exponents. At heights above 1.26 m/x the allometric exponent is 2.9, equal in women and men, and significantly different from the exponent of 2.0 implicated in the body mass index, BMI [kg/m2].
Height of humansh [m]; H [m·x-1]The height of humans, h, is given in SI units in meters [m]. Humans are countable objects, and the symbol and unit of the number of objects is N [x]. The average height of N objects is, H = h/N [m/x], where h is the heights of all N objects measured on top of each other. Therefore, the height per human has the unit [m·x-1] (compare body mass [kg·x-1]). Without further identifyer, H is considered as the standing height of a human, measured without shoes, hair ornaments and heavy outer garments.
Lengthl [m]Length l is an SI base quantity with SI base unit meter m. Quantities derived from length are area A [m2] and volume V [m3]. Length is an extensive quantity, increasing additively with the number of objects. The term 'height' h is used for length in cases of vertical position (see height of humans). Length of height per object, LUX [m·x-1] is length per unit-entity UX, in contrast to lentgth of a system, which may contain one or many entities, such as the length of a pipeline assembled from a number NX of individual pipes. Length is a quantity linked to direct sensory, practical experience, as reflected in terms related to length: long/short (height: tall/small). Terms such as 'long/short distance' are then used by analogy in the context of the more abstract quantity time (long/short duration).
MitObesity drugsBioactive mitObesity compounds are drugs and nutraceuticals with more or less reproducible beneficial effects in the treatment of diverse preventable degenerative diseases implicated in comorbidities linked to obesity, characterized by common mechanisms of action targeting mitochondria.
ObesityObesity is a disease resulting from excessive accumulation of body fat. In common obesity (non-syndromic obesity) excessive body fat is due to an obesogenic lifestyle with lack of physical exercise ('couch') and caloric surplus of food consumption ('potato'), causing several comorbidities which are characterized as preventable non-communicable diseases. Persistent body fat excess associated with deficits of physical activity induces a weight-lifting effect on increasing muscle mass with decreasing mitochondrial capacity. Body fat excess, therefore, correlates with body mass excess up to a critical stage of obesogenic lifestyle-induced sarcopenia, when loss of muscle mass results in further deterioration of physical performance particularly at older age.
VO2maxVO2max; VO2max/MMaximum oxygen consumption, VO2max, is and index of cardiorespiratory fitness, measured by spiroergometry on human and animal organisms capable of controlled physical exercise performance on a treadmill or cycle ergometer. VO2max is the maximum respiration of an organism, expressed as the volume of O2 at STPD consumed per unit of time per individual object [mL.min-1.x-1]. If normalized per body mass of the individual object, M [kg.x-1], mass specific maximum oxygen consumption, VO2max/M, is expressed in units [mL.min-1.kg-1].

References

  1. Bosy-Westphal A, Plachta-Danielzik S, Dörhöfer RP, Müller MJ (2009) Short stature and obesity: positive association in adults but inverse association in children and adolescents. Br J Nutr 102:453-61. - »Bioblast link«
  2. Deurenberg P, Andreoli A, Borg P, Kukkonen-Harjula K, de Lorenzo A, van Marken Lichtenbelt WD, Testolin G, Vigano R, Vollaard N (2001) The validity of predicted body fat percentage from body mass index and from impedance in samples of five European populations. Eur J Clin Nutr 55:973-9. - »Bioblast link«
  3. Gallagher D, Heymsfield SB, Heo M, Jebb SA, Murgatroyd PR, Sakamoto Y (2000) Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. Am J Clin Nutr 72:694-701. - »Bioblast link«
  4. Iwaniec UT, Turner RT (2016) Influence of body weight on bone mass, architecture and turnover. J Endocrinol 230: R115-30. - »Bioblast link«
  5. Misra P, Singh AK, Archana S, Lohiya A, Kant S (2019) Relationship between body mass index and percentage of body fat, estimated by bio-electrical impedance among adult females in a rural community of North India: A cross-sectional study. J Postgrad Med 65:134-40. - »Bioblast link«
  6. Romero-Corral A, Somers VK, Sierra-Johnson J, Thomas RJ, Collazo-Clavell ML, Korinek J, Allison TG, Batsis JA, Sert-Kuniyoshi FH, Lopez-Jimenez F (2008) Accuracy of body mass index in diagnosing obesity in the adult general population. Int J Obes (Lond) 32:959-66. - »Bioblast link«


MitoPedia concepts: MiP concept 


Labels:






MitoPedia:BME