M. Lassek: Den Wechsel miteinander gestalten: Elternberatung und Übergang
AHS13 Will Lassek MD -- Why Women Need Fat: Three Evolutionary Puzzles
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Transcript of AHS13 Will Lassek MD -- Why Women Need Fat: Three Evolutionary Puzzles
WHY DO WOMEN
NEED FAT?
Will Lassek
Look here first
Who is the most attractive
imaginary woman?eg. animated films,
video games,comics, graphic novels
Jessica Rabbit“most attractive
imaginary woman”
650 undergradsof Steve Gaulin“sexiest cartoon
character”Cadbury contest
What is hermost
unusualattribute?
Jessica Rabbit
Waist/Hip Ratio: 38%
Waist/HeightRatio: 15%(10 inches)
38% 68% 74%
Playmate undergrad
WAIST/HIP
15% 10 in
36%24 in
44%28 in
Playmate undergrad
WAIST/HEIGHT
WHERE DOMEN LOOK
FIRST &LONGEST?
Cornellisen, et al. 2009
eye tracking:WAIST is
where men look first and most when judging attractiveness
Look here first
Why should we care what menfind attractive?
Look here first
Men should admire qualitiesthat help women havechildren that survive
HOW IS WOMEN’SWAIST FAT
CONNECTEDTO HAVING CHILDREN?
14161820222426283032
20 22 24 26 28 30 32 34 36Waist, inches
BM
IWaist & BMI (Body Mass Index)
small waistrequires low BMI
correlation = 0.93
Playmatesundergrads
Jessica’s BMI?
Jessica Rabbit
waist/height15%
predictedBMI:
10(from waist, hip, height)
Average weight of young US women by BMI
90
100
110
120
130
140
150
16 17 18 19 20 21 22 23 24 25
BMI
Pou
nds
BMI <20<120 pounds
Men prefer women with low BMI’s Martin Tovee, et al. 1999
attractivenessscores
0
10
20
30
40
50
14 15 16 17 18 19
BMI
Per
cent
Cumulative BMI % age 18-20, 1971-75(before the obesity epidemic)
half of young women had BMI’s <20
HOW DOES A MOTHER’S
SMALL WAIST & LOW BMI
AFFECT HER CHILDREN?
OVULATORY INFERTILITY & BMI: 116,671 nurses, Rich-Edwards 2002
21
BMI<21:HARDER
TOGET
PREGNANT
In foraging/subsistence populations thinner women have fewer children
Hadza
Marlowe 04
Andes
Mueller 79
Papua New
Guinea
Brush 93
0 1 2 3
Low BirthWeight
Preterm
Hospital
<1919-2425+
Lower BMI, bad for infants
(infant)Murakami 2005
Low BMI & fetal or infant death
the lower the BMI,the moreinfant deaths
23
England
BMITennant, 2011
17
PUZZLEWHY DO MEN PREFER WOMEN
WITH LOWER FERTILITY& LESS HEALTHY INFANTS?
AND (OR) WHY DO MOST YOUNG
WOMEN HAVE SMALL WAISTS& LOW BMI’S?
WHAT HAPPENS TO A FIRST-TIME
AMERICAN MOTHER EVERY 86 SECONDS?
WH, 1932 (1847) Catherine
FTA, 1932 (1929)
Evolution of pelvis in humans
pelvis changed to allowupright walking and running
a
Smallest pelvic outlet dimension: interspinous diameter ~ 9 cm
Interspinous
Average biparietal diameter at term: 9.5 cm
humans have much less ofbrain growthbefore birth,but head isstill too big
chimpanzee
human
Almost half of babies from “normal”vaginal deliveries have bleeding in brain
46%
Rooks, 2008
LARGER HEAD LEADS TO BLOCKED LABORAND DEATH IN CHILDBIRTH
Spain, ~1100 AD
HOW COMMON WASDEATH IN CHILDBIRTH
BEFORE C-SECTIONS?
WHICHSEX
LIVES LONGER?
Average age at death,US 1999-2010
60 62 64 66 68 70 72 74 76
men
women
Percent surviving to age 65,US 1999-2010
60 65 70 75 80
men
women
Average adult age at death:30,000 BC to 1799 AD
26 28 30 32 34 36
~3000 skeletons examined by Larry Angel, 1984
men
women
Sweden, 1800-1899Hogberg, 1985
1 in 14 mothers died in childbirth
Sierra Leone 2.0%Afghanistan 1.9Malawi 1.8Angola 1.7Niger 1.6Tanzania 1.5Rwanda 1.4Mali 1.2
Maternal deaths in 2000, WHO
many mothers still die inchildbirth
Sierra Leone 1/50
0
5
10
15
20
25
1 2 3 4 5 6Birth
% C
-sec
tion
sFirst C-sections by birth
most risk ofblocked labor with first birth
US, 1990
Every 86 seconds a first-time American mother has a C-section
WHAT IS THE BENEFIT OF A
SMALLER WAIST& LOWER BMI
IN A FIRST-TIME MOTHER?
33.4
33.6
33.8
34.0
34.2
34.4
34.6
34.8
10-14 15-19 20-24 25-29 30-34 35-39
BMI before pregnancy
Hea
d s
ize
cmLower BMI, smaller newborn
head for 1st birth
05
10152025303540
12 14 16 18 20 22 24 26 28BMI before pregnancy
Per
cen
t C
-sec
tion
sLower BMI, fewer C-sections
for 1st birth
less blocked babies
High blood pressure duringpregnancy can also be bad
preeclampsia/eclampsia
0
1
2
3
4
1 2 3 4 5 6 7Pregnancy
Per
cen
t More high blood pressure with
first pregnancy
468
1012141618202224
14 16 18 20 22 24 26 28 30
Per
cent
pre
ecla
mps
iaBMI & high blood pressure
in 1st time mothers
lower BMI,less risk
WHAT ARE THE BENEFITS OF A
SMALLER WAIST& LOWER BMI
IN A FIRST-TIME MOTHER? (2)
1. LESS RISK OF MOTHER & CHILD
DYING IN CHILDBIRTH2. LESS HIGH
BLOOD PRESSURE
WHAT HAPPENS TOWOMEN’S WAIST FAT
(AND WEIGHT)AFTER
HAVING A CHILD?
252627282930313233
15 15 20 25 30 35 40 45 50Age Group
Wai
st, i
nche
sMinimum waist (inches) in women
with children, US 1988-94
NP
120
125
130
135
140
145
150
18 22 26 30 34 38 42 46Age
Wei
ght,
poun
dsAverage weight in American women
before obesity epidemic 1959-61
as add 25-30 pounds,more new fat in waist
20 21 22 23 24 25 26
Age 17-18
All Adults
BMI
Average BMI in European women
122 pounds
150 pounds
WHY IS IT BENEFICIALTO HAVE MORE
WAIST FAT AFTER HAVING A CHILD?
0 1 2 3
LBW
Preterm
Hospital
Adjusted Odds Ratio
<1919-2425+
Bigger waist, bigger babies
(infant)Murakami 2005
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
0 1 2 3 4 5 6Births
Pel
vic
wid
th, c
mPelvic width and births, NHANES III
birth canal expands with each birth, soless blocked labor
LESS HIGH BLOOD PRESSURE2nd CHILD WITH SAME FATHER
30
40
50
60
70
80
90
100
110
120
38 40 42 44 46 48 50 52 54 56 58 60 62
Waist/Height x 100
Insu
linBigger waist, more insulin resistance
more insulin resistance =more sugar for baby
= bigger baby
708090
100110120130140150160170
36 38 40 42 44 46 48 50 52 54 56 58 60 62
Waist/height x 100
Tri
glyc
erid
esBigger waist, more triglycerides
more fat inmother’s blood =bigger baby
0102030405060708090
100
20 21 22 23 24 25 26 27 28 29 30 31+
Cumulative BMI in women 15+
Per
cent
BMI in women 15+ in 190 countries
2/3rds are 25+“overweight”
WHERE WOMEN
DON’T ADD WAIST FAT,
CHILDREN SUFFER
(CONTROLLING FOR INCOME)
5
10
15
20
<22 22 23 24 25 26 27 28 29+
Female BMI
Low
Bir
th W
eigh
t %
Low birth weight & average BMI in women (income controlled)
0
10
20
30
40
50
<23 23 24 25 26 27 28 29+Female BMI
Dea
ths
per
100
0 b
irth
sNewborn death rate & average BMI
in women (income controlled)
25
50
75
100
125
<23 23 24 25 26 27 28 29+
Female BMI
Dea
ths
per
1000
bir
ths
Child death rate & average BMI in women (income controlled)
SO, WHY DOES A WOMAN
NEED WAIST FAT?
WAIST FATDETERMINESTHE SIZE OF
HER CHILDREN
WHAT ABOUT
FAT in the HIPS
& LEGS?
Jessica Rabbit
HIP/HEIGHT= 53%(36 in)
53% 53%
Playmateundergrad
53%
BMI <20
Hip/height
Men’s ranking of desirability ofwomen’s body areas
Rank Score 1-5Chest 1 4.13
Buttocks 2 4.09
Legs 3 4.04
Hips 4 3.98
Montoya, 2006
Almost all cultures value fat in women’s legs & hips
Brown & Konner, 1987
What % of weight is fat?
Ambelosi baboon
What % of weight is fat?
bear ready to hibernate
What % of weight is fat?
typicalundergrad
height: 64”weight: 132 lb
BMI: 22.2fat: 32%(42 lb)
WHY DO WOMENNEED
SO MUCH FAT?
2/3rds of fat is in hips & legs
(white = fat)
LOWER BODY FATIS LOCKED AWAY
UNTIL LATE INPREGNANCY
1800
2000
2200
2400
2600
0 1-6 7 8 9 nurseMonths of pregnancy
COST
30%of fetalgrowth
Mothers eat less in late pregnancy& while nursing (calories/day)
AS EAT LESS,LOWER BODY FATIS MOBILIZED IN
LATE PREGNANCY& WHILE NURSING
~1 ounce/day
WHAT IS INONE OUNCE OF LOWER-BODY
FAT?
0 50 100 150 200 250
human
baboon
beef cow
guinea pig
sheep
rabbit
rat/pig
Maternal energy cost of nursing: cals/kgPrentice 1988
300 calories/day
2% FAT
WHAT IMPORTANTORGAN IN
A NEW BABYGROWS THE MOST
& ADDS THE MOST FAT?
Brain triples in size in 1st year
300
400
500
600
700
800
900
Bra
in w
eig
ht,
g
Fat = 52% dry weight of brain
ProteinFat
Nerve cells are mostly membranes made of fat with embedded proteins
Nerve cell membranes would cover 5 football fields
DHA = 1/3rd of membrane fat
DHA
DOCOSAHEXAENOIC ACID
DHA (docosahexaenoic acid) omega-3
22 carbons6 double bonds
omega-3 fats must come from diet
DHA is active in every part of nerve cell
Calderon 07makes & grows dendrites
transmits signal
makessynapse work
grows axon
preserves
60
65
70
75
80
85
low medium highMother's dietary DHA
% h
igh
er I
QChildren of mothers with more DHA
while pregnant have higher verbal IQ’s
Hibbeln, 07
420
440
460
480
500
520
540
1 2 3 4+
Milk DHA index
Mat
h Sc
ore
More DHA in mother’s milk: higherPISA math score in 28 countries
WHERE DOES MILK DHA
COME FROM?
Where does milk DHA come from?
BODY FAT80%
CURRENTDIET
Fidler 2000
DHA mainly from stored fat80% of 120 mg
MILK DHA = 96 mg*
ONE OUNCEOF FAT =
96 mg* DHA
*120 mg DHA/day* European mothers
SO, WHY DO WOMENNEED SO MUCHLOWER-BODY
FAT?
LOWER-BODYFAT PROVIDES
ESSENTIAL FATSNEEDED BY BRAIN
WHY AREOUR
NEWBORNBABIESSO FAT?
TYPICAL NEWBORNHAS 2 POUNDS OF FAT
WITH1500 MILLIGRAMS OF
DHA
(1.6%)
HOW CAN WOMEN STORE MORE DHA WHEN
DHA % IN FAT IS LOWBECAUSE OF
LOW DHA FROM DIET?
Percent DHA in body fatImaichi 65, Leaf 95
0.0 0.2 0.4 0.6 0.8 1.0 1.2
US
Japan
0
5
10
15
20
25
30
1 2 3 4 5 6+Milk DHA index
Fem
ale
obes
ity
%DHA in mother’s milk &
female obesity in 43 countriesUSA?
Japan?paleolithic?
161820222426283032
30 32 34 36 38 40 42 44 46 48 50 52 54Waist/Height x 100
BM
IWaist/Height & BMI (Body Mass Index)
small waistrequires low BMI
correlation = 0.93
Playmates undergrads
Jessica?
1%2%
5
6
7
8
9
10 to 14 15 to 19 20 to 29
BMI
Low
bir
th w
eigh
t %
Lower BMI mothers have more low birth weight babies