Obesity epidemic and carbohydrates

Carbohydrates andCarbohydrates and
Obesity epidemicObesity epidemic
Dr.Khaled Mahmoud Abd ElazizDr.Khaled Mahmoud Abd Elaziz
Associate professor of public health andAssociate professor of public health and
preventive medicinepreventive medicine
Faculty of Medicine Ain Shams UniversityFaculty of Medicine Ain Shams University
Cairo EgyptCairo Egypt
Khaled M. Abd ElazizKhaled M. Abd Elaziz

The Epidemic distributionThe Epidemic distribution
Definition of obesityDefinition of obesity
Root causes of epidemicRoot causes of epidemic
Classification of Carbohydrates and glycemicClassification of Carbohydrates and glycemic
indexindex
Studies with low carb for weight reductionStudies with low carb for weight reduction
Effect of low carb on severe obesityEffect of low carb on severe obesity

The Fat World (Globesity)The Fat World (Globesity)

Ancient Egypt:Ancient Egypt:
Lipid disorders cannot be measured;Lipid disorders cannot be measured;
but premature atheromatous disease and obesitybut premature atheromatous disease and obesity
occurred, and cholesterol-rich foods (i.e., beef,occurred, and cholesterol-rich foods (i.e., beef,
pork, and eggs) were plentiful for the upper classes thepork, and eggs) were plentiful for the upper classes the
group that usually was embalmed. The diet of the lowergroup that usually was embalmed. The diet of the lower
classes was primarily vegetarian, sotheoretically theclasses was primarily vegetarian, sotheoretically the
prevalence of atheromatous disease should have beenprevalence of atheromatous disease should have been
lower at the bottom of the social and economic scale.lower at the bottom of the social and economic scale.
Unfortunately, well preserved bodies of poorer EgyptiansUnfortunately, well preserved bodies of poorer Egyptians
are too few to permitare too few to permit comparison.comparison.

Obesity in the past meant WEALTHObesity in the past meant WEALTH

Obesity epidemic and carbohydrates

Obesity PandemicObesity Pandemic
Alarming increase over the past twoAlarming increase over the past two
decades--- considered a pandemic rightdecades--- considered a pandemic right
nownow
WHO estimates 315 millions are clinicallyWHO estimates 315 millions are clinically
obese personsobese persons
1 billion people around the globe are1 billion people around the globe are
overweightoverweight
22 million children under 5 around the world22 million children under 5 around the world
are either obese or overweightare either obese or overweight

Obesity in USAObesity in USA
--2 out of 3 adults in US are over weight 76%2 out of 3 adults in US are over weight 76%
1 out of three adults are obese 33%1 out of three adults are obese 33%
9 millions US children are obese9 millions US children are obese
-the second leading cause of preventable-the second leading cause of preventable
death in the United Statesdeath in the United States
--An estimatedAn estimated 325000 deaths and between 4.3%325000 deaths and between 4.3%
and5.7% of direct health care costs (approximatelyand5.7% of direct health care costs (approximately
$39-$52 billion)$39-$52 billion)
Deaths related toDeaths related to obesity annually equals (alcohol,obesity annually equals (alcohol,
drug abuse, Motor vehicle accidents, murders,drug abuse, Motor vehicle accidents, murders,
fires, suicides COMBINED)fires, suicides COMBINED)

Enigmatic epidemicEnigmatic epidemic
According to the Center For Disease Control (CDC), theAccording to the Center For Disease Control (CDC), the
percentage of overweight children aged 6-11 years haspercentage of overweight children aged 6-11 years has
almost doubled since the early 1980's. The percentage ofalmost doubled since the early 1980's. The percentage of
overweight adolescents has risen by nearly 300 percent.overweight adolescents has risen by nearly 300 percent.
Huge health problem that is not taken care of by policyHuge health problem that is not taken care of by policy
makers.makers.
An epidemic that has too many root causes could beAn epidemic that has too many root causes could be
interplayinginterplaying

Obese and overweight face risksObese and overweight face risks
cardiovascular diseases and anginacardiovascular diseases and angina
Diabetes Type IIDiabetes Type II
cancerscancers
musculoskeletal conditionsmusculoskeletal conditions
hypertension/ high blood cholesterolhypertension/ high blood cholesterol
StrokeStroke
Gall stonesGall stones
gout osteoarthritisgout osteoarthritis
sleep apneasleep apnea
Respiratory diseases (asthmaRespiratory diseases (asthma
Pregnancy complications and poor reproductive healthPregnancy complications and poor reproductive health
bladder problemsbladder problems
psychological disorderspsychological disorders

The toxic environment
880 calories for only 2 US dollars

Obesity ?????Obesity ?????
Defined as a complex, multifactorial,Defined as a complex, multifactorial,
chronic disease involving environmentalchronic disease involving environmental
(social and cultural),(social and cultural),
genetic, physiologic, metabolic, behavioral,genetic, physiologic, metabolic, behavioral,
and psychological componentsand psychological components

ObesityObesity
Measured by BMI levels:Measured by BMI levels:
normal range 18.5-24.99normal range 18.5-24.99
overweight 25-29.99overweight 25-29.99
Grade I obesity 30-34.99 moderate riskGrade I obesity 30-34.99 moderate risk
Grade II obesity 35-39.99 severe riskGrade II obesity 35-39.99 severe risk
Grade III > 40.0 very severe riskGrade III > 40.0 very severe risk

Developed vs Developing countriesDeveloped vs Developing countries
In Egypt and developing countriesIn Egypt and developing countries
overweight could reach 66%overweight could reach 66%
Why there is an epidemic thereWhy there is an epidemic there

The consistent finding is that women in familiesThe consistent finding is that women in families
that are resource-constrained as measured bythat are resource-constrained as measured by
poverty, food insecurity or both – are more likely topoverty, food insecurity or both – are more likely to
be obese.be obese.
Poverty and food insecurity were not shown to bePoverty and food insecurity were not shown to be
associated with obesity in men.associated with obesity in men.

Food insecurity is associatedFood insecurity is associated
with obesitywith obesity (To wnse nd 20 0 1 )(To wnse nd 20 0 1 )
Percent of overweight
women
Food
Secure
Mildly
Food
Insecure
Moderatel
y Food
Insecure
34% 41% 52%

The obesity pandemic originated in the US andThe obesity pandemic originated in the US and
crossed to Europe and the world’s other richcrossed to Europe and the world’s other rich
nations before, remarkably, it penetrated even thenations before, remarkably, it penetrated even the
world’s poorest countries especially in their urbanworld’s poorest countries especially in their urban
areas. The pandemic is transmitted throughareas. The pandemic is transmitted through
the vectors ofthe vectors of
subsidized agriculturesubsidized agriculture
multinational companies providing cheap, highlymultinational companies providing cheap, highly
refined fats, oils, and carbohydratesrefined fats, oils, and carbohydrates
labour-saving mechanized devices,labour-saving mechanized devices,
affordable motorized transport, andaffordable motorized transport, and
the seductions of sedentary pastimes such asthe seductions of sedentary pastimes such as
television.television.

Caloric intake and obesity??Caloric intake and obesity??
A longitudnal study in Lousiana from 1973-1988 notedA longitudnal study in Lousiana from 1973-1988 noted
that total caloric intake for 10 yrs old children remainedthat total caloric intake for 10 yrs old children remained
virtually unchanged.virtually unchanged.
But a national health and nutrition study in USA inBut a national health and nutrition study in USA in
2000 shows greater increase in caloric intake for2000 shows greater increase in caloric intake for
adolescent females .adolescent females .
Agriculture and food studies shows a increase intake ofAgriculture and food studies shows a increase intake of
calories in 1990s.calories in 1990s.

Decreased physical activity to be blamed ??Decreased physical activity to be blamed ??
Studies shows increase in caloric intake, could reducedStudies shows increase in caloric intake, could reduced
caloric expenditure is a significant contributor to currentcaloric expenditure is a significant contributor to current
obesity epidemic.obesity epidemic.
To date , this hypothesis unproven.To date , this hypothesis unproven.
Assessing the contribution of lack of exercise to obesity isAssessing the contribution of lack of exercise to obesity is
hampered by lack of research. According to existinghampered by lack of research. According to existing
surveys, only 20 percent of the population are frequentsurveys, only 20 percent of the population are frequent
exercisers. In addition, only a small minority of children (1exercisers. In addition, only a small minority of children (1
in 5) regularly participate in after-school sports or extra-in 5) regularly participate in after-school sports or extra-
curricular physical activity. Among teenagers andcurricular physical activity. Among teenagers and
adolescents aged 12-17, the plunge is 41 percent.adolescents aged 12-17, the plunge is 41 percent.

Watching television for long hours ??Watching television for long hours ??
Longitudinal studies have been unable to demonstrateLongitudinal studies have been unable to demonstrate
physical inactivity in children predicts excessive weight gain.physical inactivity in children predicts excessive weight gain.
Cross sectional studies have shown modest associationCross sectional studies have shown modest association
between obesity and television viewing for children althoughbetween obesity and television viewing for children although
other studies failed to demonstrate this association.other studies failed to demonstrate this association.
A 2 year longitudinal study on girls 6A 2 year longitudinal study on girls 6thth
to 7to 7thth
grade found thatgrade found that
the hours of after school television were not associated withthe hours of after school television were not associated with
baseline or longitudinal changes in BMI or triceps skinfoldbaseline or longitudinal changes in BMI or triceps skinfold
thickness.thickness.

Genetic root cause??Genetic root cause??
Thus genetic causes are unlikely to be significant.Thus genetic causes are unlikely to be significant.
Because while a predisposition to obesity can beBecause while a predisposition to obesity can be
inherited, the fact that obesity has increased soinherited, the fact that obesity has increased so
much in the last few decades appears to discountmuch in the last few decades appears to discount
genetics as a major main cause. Also, the fact thatgenetics as a major main cause. Also, the fact that
each succeeding generation is heavier than theeach succeeding generation is heavier than the
last indicates that changes in our environment arelast indicates that changes in our environment are
playing the key role.playing the key role.

Genetic and environmental cause??Genetic and environmental cause??
Obesity tends to run in families, suggesting aObesity tends to run in families, suggesting a
genetic link. Yet families also share commongenetic link. Yet families also share common
dietary, physical exercise, attitude and lifestyledietary, physical exercise, attitude and lifestyle
habits that may also contribute to obesity.habits that may also contribute to obesity.
Separating these from purely genetic factors is notSeparating these from purely genetic factors is not
an easy statistical or diagnostic task.an easy statistical or diagnostic task.

Environmental cause??Environmental cause??
In view of the sudden rise in weight levels - whichIn view of the sudden rise in weight levels - which
is a worldwide trend as reflected in the new wordis a worldwide trend as reflected in the new word
"globesity" - environmental factors must be the"globesity" - environmental factors must be the
prime cause of modern obesity.prime cause of modern obesity.

Secular Changes in EnvironmentSecular Changes in Environment
 Food eaten outside of homeFood eaten outside of home
 Food availabilityFood availability
 Portion size shiftsPortion size shifts
 Food marketingFood marketing
 TransportationTransportation
 Neighborhood safetyNeighborhood safety
 City planningCity planning
 TV, video, computer workTV, video, computer work
 Economy and employment shiftsEconomy and employment shifts

Are environmental contributors toAre environmental contributors to
obesity greater for the poor?obesity greater for the poor?
 A healthy basket of food has been found to costA healthy basket of food has been found to cost
more in disadvantaged areas than in affluentmore in disadvantaged areas than in affluent
areas (Acheson D, 1998)areas (Acheson D, 1998)
 The food industry markets mass, low-qualityThe food industry markets mass, low-quality
products with higher fat and sugar content toproducts with higher fat and sugar content to
sectors with less purchasing power (Aguirre P,sectors with less purchasing power (Aguirre P,
Obesity and Poverty, 2000)Obesity and Poverty, 2000)

More potential environmentalMore potential environmental
contributors to obesity….contributors to obesity….
 Low SES was related to lessLow SES was related to less
participation in physical activities inparticipation in physical activities in
school PE, as well as programsschool PE, as well as programs
outside of school (Sallis, 1996)outside of school (Sallis, 1996)
 Low SES among adolescents wasLow SES among adolescents was
related to decreased participation inrelated to decreased participation in
vigorous physical activity, even aftervigorous physical activity, even after
controlling for gender andcontrolling for gender and
race/ethnicity (Lowry, 1996).race/ethnicity (Lowry, 1996).

Family Influence - A Major Contributory CauseFamily Influence - A Major Contributory Cause
to Obesityto Obesity
Parental behavioral patterns concerning shopping,Parental behavioral patterns concerning shopping,
cooking, eating and exercise, have an importantcooking, eating and exercise, have an important
influence on a child's energy balance andinfluence on a child's energy balance and
ultimately their weight. Thus family diet andultimately their weight. Thus family diet and
lifestyle are important contributory causes tolifestyle are important contributory causes to
modern child obesity, especially at a time of risingmodern child obesity, especially at a time of rising
affluence. Since obese children and adolescentsaffluence. Since obese children and adolescents
frequently grow up to become obese adults, it'sfrequently grow up to become obese adults, it's
clear that family influence also extends to adultclear that family influence also extends to adult
obesity.obesity.

The Obesity Epidemic: Metabolic ImprintingThe Obesity Epidemic: Metabolic Imprinting
on Genetically Susceptible Neural Circuitson Genetically Susceptible Neural Circuits
Barry E. Levin 2000Barry E. Levin 2000

The apparent obesity epidemic in theThe apparent obesity epidemic in the
industrialized world is not explainedindustrialized world is not explained
completely by increased food intake orcompletely by increased food intake or
decreased energy expenditure.decreased energy expenditure.
Once obesity develops in geneticallyOnce obesity develops in genetically
predisposed individuals, their obese bodypredisposed individuals, their obese body
weight is avidly defended against chronicweight is avidly defended against chronic
caloric restrictioncaloric restriction

Formation of new neuralFormation of new neural circuits involved in energycircuits involved in energy
homeostasis might underlie the near permanencehomeostasis might underlie the near permanence
of the obese body weight. Such neural plasticityof the obese body weight. Such neural plasticity
can occur during both nervous systemcan occur during both nervous system
developmentdevelopment and in adult life.and in adult life.
This enhanced obesityThis enhanced obesity may then be passed on tomay then be passed on to
subsequent generations in a feed-forward, upwardsubsequent generations in a feed-forward, upward
spiral of increasing body weight acrossspiral of increasing body weight across
generations. Such findings suggest a form ofgenerations. Such findings suggest a form of
”metabolic imprinting” upon genetically”metabolic imprinting” upon genetically
predisposed neural circuitspredisposed neural circuits involved in energyinvolved in energy
homeostasishomeostasis

Is No to Carbs is theIs No to Carbs is the
answer ? To Obesiyanswer ? To Obesiy
crisiscrisis

CarbohydratesCarbohydrates
 Carbohydrates serves wide variety of functions in theCarbohydrates serves wide variety of functions in the
bodybody
 1-simple carbohydrates1-simple carbohydrates
 Good source of energy to the bodyGood source of energy to the body
 Spares protein for builiding, repairing and maintingSpares protein for builiding, repairing and mainting
body tissuesbody tissues
 Only source of energy to the brainOnly source of energy to the brain
 Important for cell fertilization , growth andImportant for cell fertilization , growth and
developmentdevelopment
 Breaks up fatty acids preventing ketosisBreaks up fatty acids preventing ketosis

CarbohydratesCarbohydrates
 2-Complex carbohydrates2-Complex carbohydrates
 Starch and fibers must be broken down into simpler formsStarch and fibers must be broken down into simpler forms
of sugar in order to be used.of sugar in order to be used.
 Provide a long term energy without the “hit and run” energyProvide a long term energy without the “hit and run” energy
levels of the simple carbohydrateslevels of the simple carbohydrates
 Fibers are important in the removal of toxic wastesFibers are important in the removal of toxic wastes
 Carbohydrates should serve 45% of the total calories of aCarbohydrates should serve 45% of the total calories of a
healthy diethealthy diet
 This classification is not enough to understand metabolismThis classification is not enough to understand metabolism
of carbohydrates.of carbohydrates.

Glycemic index Jenkins 1981Glycemic index Jenkins 1981
 Classification of carbohydrates in terms of glucose andClassification of carbohydrates in terms of glucose and
insulin responses this is conventionally expressed in theinsulin responses this is conventionally expressed in the
term glycemic indexterm glycemic index
 The gylcemic index of carb containing food describes theThe gylcemic index of carb containing food describes the
area under the post prandial glucose curve for 50 g of thatarea under the post prandial glucose curve for 50 g of that
carb in relation to 50 g of glucose.carb in relation to 50 g of glucose.
 White bread is an example of carb with high glycemicWhite bread is an example of carb with high glycemic
index, digested quickly into glucose and causing bloodindex, digested quickly into glucose and causing blood
sugar to spike quicklysugar to spike quickly
 In contrast brown rice is digested more slowly causing aIn contrast brown rice is digested more slowly causing a
lower more gentle change of blood sugar (low glycemiclower more gentle change of blood sugar (low glycemic
index)index)

Link between high glycemic index andLink between high glycemic index and
obesityobesity
 Three mechanisms are involvedThree mechanisms are involved
 11. high glycemic carbohydrate. high glycemic carbohydrate leads toleads to
postprandial hyperinsulinemia and excessivepostprandial hyperinsulinemia and excessive
weight gainweight gain
 2. sugar containing drinks tend to displace2. sugar containing drinks tend to displace
energy from other food sources leading toenergy from other food sources leading to
increase energy intakeincrease energy intake
 3. high glycemic index food promotes hyper3. high glycemic index food promotes hyper
phagiaphagia

Glycemic load of dietGlycemic load of diet
 Multiplication of GI X amount of carbohydrateMultiplication of GI X amount of carbohydrate
in dietin diet
 Leeds 2002Leeds 2002
 Low-GI dietsLow-GI diets reduce plasma fatty acids and mayreduce plasma fatty acids and may
suppress production or release of signalingsuppress production or release of signaling
hormones from adipose tissue, in turn tending tohormones from adipose tissue, in turn tending to
reverse dyslipidemia and insulin resistancereverse dyslipidemia and insulin resistance

Increased consumption of refined CHO andIncreased consumption of refined CHO and
diabetes Type II USA (Lee S 2004)diabetes Type II USA (Lee S 2004)
It is ecological correlation studyIt is ecological correlation study
Relating per capita nutrient consumption in theRelating per capita nutrient consumption in the
United States between 1909 and 1997 obtainedUnited States between 1909 and 1997 obtained
from the US Department of Agriculture wasfrom the US Department of Agriculture was
compared with the prevalence of type 2 diabetescompared with the prevalence of type 2 diabetes
obtained from the Centers for Disease Control andobtained from the Centers for Disease Control and
PreventionPrevention..

Univariate analysis showed positive correlationUnivariate analysis showed positive correlation
between use of dietary fat, carbohydrartes,between use of dietary fat, carbohydrartes,
protein, corn syrup and total energy intake.protein, corn syrup and total energy intake.
Multivariant nutrition density model showed only twoMultivariant nutrition density model showed only two
independent risks:independent risks:
Corn syrup had a positive correlation P0.03Corn syrup had a positive correlation P0.03
Fiber was negatively correlated with type II DM P<0.01Fiber was negatively correlated with type II DM P<0.01
Protein and fats was not associated when controlling forProtein and fats was not associated when controlling for
total energy intaketotal energy intake

Their conclusion isTheir conclusion is
Increasing intakes of refined carbohydrate (cornIncreasing intakes of refined carbohydrate (corn
syrup) concomitant with decreasing intakes of fibersyrup) concomitant with decreasing intakes of fiber
paralleled the upward trend in the prevalence ofparalleled the upward trend in the prevalence of
type 2 diabetes observed in the United Statestype 2 diabetes observed in the United States
during the 20th centuryduring the 20th century..

Longituidnal studyLongituidnal study
A four year follow up longitiudnal study (Ma et al.)A four year follow up longitiudnal study (Ma et al.)
indicated a positive association between GI andindicated a positive association between GI and
not GL and body mass index.not GL and body mass index.
In a systemic review most of the short term studiesIn a systemic review most of the short term studies
in humans demonstrated a direct associationin humans demonstrated a direct association
between consumption of high GI foods or liquidsbetween consumption of high GI foods or liquids
and increased subsequent hunger and decreasedand increased subsequent hunger and decreased
satiety. (vicious circle)satiety. (vicious circle)

Clinical trialsClinical trials
Several recent long term clinical trials on the role ofSeveral recent long term clinical trials on the role of
GI or GL in weight loss have yielded mixed results.GI or GL in weight loss have yielded mixed results.
In a 10 week randomized interventional trial a low GIIn a 10 week randomized interventional trial a low GI
diet induced greater weight and fat loss compareddiet induced greater weight and fat loss compared
with high GI diet but difference did not reachwith high GI diet but difference did not reach
statistical difference.statistical difference.

Clinical trialsClinical trials
A 12 weeks randomized trial with a larger sampleA 12 weeks randomized trial with a larger sample
size found that a low GI diet especially whensize found that a low GI diet especially when
combined with higher amount of proteins resultedcombined with higher amount of proteins resulted
in significantly great FAT loss (but not greaterin significantly great FAT loss (but not greater
weight loss) compared with a high GI diet.weight loss) compared with a high GI diet.

Systematic reviewsSystematic reviews
1- insufficient evidence that an exchange of sugar for1- insufficient evidence that an exchange of sugar for
non sugar carobhydrates in the context of energynon sugar carobhydrates in the context of energy
constricted diet results in lower body weightsconstricted diet results in lower body weights
2-obesrvational studies suggest a possible2-obesrvational studies suggest a possible
relationship between consumption of sugarrelationship between consumption of sugar
sweetened beverages and body weight but notsweetened beverages and body weight but not
from randomized controlled trialsfrom randomized controlled trials

Systematic reviewsSystematic reviews
3-There is insufficient evidence to support liquid and3-There is insufficient evidence to support liquid and
solid sugar intake and body weight controlsolid sugar intake and body weight control
4-There is some, although not consistent, evidence4-There is some, although not consistent, evidence
of a lower body weight on diets with a lowerof a lower body weight on diets with a lower
glycemic load. There is currently no convincingglycemic load. There is currently no convincing
evidence of the role of GI independent of GL.evidence of the role of GI independent of GL.

Further readingsFurther readings
 Obesity epidemiology Frank HU Oxford 2008Obesity epidemiology Frank HU Oxford 2008
 The Rise of obesity in Europe Derek J 2009The Rise of obesity in Europe Derek J 2009
 Obesity Epidemiology, Pathophysiology and prevention DebasisObesity Epidemiology, Pathophysiology and prevention Debasis
G 2007G 2007
 Arnold H. Slyper 2004The Pediatric obesity epidemic: causesArnold H. Slyper 2004The Pediatric obesity epidemic: causes
and contraversiesand contraversies
 Brehm BJ 2004 A randomized trial comparing a very low calorieBrehm BJ 2004 A randomized trial comparing a very low calorie
carb diet and a calorie-restricted low fat diet on body weight andcarb diet and a calorie-restricted low fat diet on body weight and
CVS risk factors in healthy women 2004CVS risk factors in healthy women 2004
 Roberts SB 2000 High glycemic index foods, hunger, andRoberts SB 2000 High glycemic index foods, hunger, and
obesity: is there a connectionobesity: is there a connection

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