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Why Everything You Know About Obesity Might Be
WRONG
Simon Feng MD
What We EatA calorie is a calorie is a calorie?(AKA all calories are created equal)
100 CaloriesFrom Sugar
100 CaloriesFrom Fat
100 CaloriesFrom Protein
= =
EQUAL TO A BUNSEN BURNER !!!
What We EatENERGY INTAKE
ENERGY EXPENDITURE
What We EatENERGY INTAKE
ENERGY EXPENDITURE
• Resting Metabolic Rate (RMR)• Physical Activity• Thermic Effect of Food (TEF)• Energy of Growth• Thermogenesis
What We Eat
Thermic Effect of Food (TEF)
• TEF = Energy expended in order to consume, digest, absorb, transport, and store food energy
• Part of our ENERGY EXPENDITURE
What We Eat
Thermic Effect of Food (TEF)
• TEFprotein > TEFfat > TEFsugar
What We Eat
100 CaloriesFrom Sugar
100 CaloriesFrom Fat
100 CaloriesFrom Protein
= =
TO A BUNSEN BURNER:
~98 CaloriesFrom Sugar
~95 CaloriesFrom Fat
~70 CaloriesFrom Protein
After Adjusting for TEF
What We Eat
100 CaloriesFrom Sugar
100 CaloriesFrom Fat
100 CaloriesFrom Protein
= =
TO A BUNSEN BURNER:
~98 CaloriesFrom Sugar
~95 CaloriesFrom Fat
~70 CaloriesFrom Protein
After Adjusting for TEF
TEF• Helps explain low-carb diets• Depends on degree of processing– whole grain > processed white bread– fat in bacon > stick of butter– eating an orange > orange juice
• Related to Glycemic Index
How Much We EatCorollary to Good Food vs. Bad
Food Dichotomy• “I can eat as much as I like of
good foods”–e.g. salads, fruits and vegetables, lean
meat, etc.
How Much We Eat
Elephants, rhinos, cows and horses are all herbivores
• These animals get massive despite being vegetarians who don’t even use salad dressing
Lack of Physical Activity
If lack of physical activity caused obesity, then
• Why doesn’t every quadriplegic in a wheelchair weigh 400 lbs
• How come sumo wrestlers and NFL linebackers get so big despite all that exercise
HUNGER vs. APPETITE
HUNGER vs. APPETITE
Hunger:A sensation resulting from lack of foodA biological signal stimulating the
consumption of food
Appetite A desire rather than need for foodNon-biological
HUNGER vs. APPETITE
HungerHunger is the word that is usually applied to
the sensation of needing food. Appetite is a more hedonic term; it encompasses the enjoyment of eating, the desire to eat and may be applied to the desire to eat certain food itemsRead N. Role of gastrointestinal factors in hunger and satiety in man. The Proceedings of the Nutrition Society. May 1 1992;51(1):7-11.
HUNGER vs. APPETITE
Appetite A strong desire, esp. for food. Appetite differs
from hunger in that the latter is an uncomfortable sensation caused by the lack of food, whereas appetite is a pleasant sensation based upon previous experience that causes one to seek food for the purpose of tasting and enjoying(Taber’s Medical Dictionary)
HUNGER vs. APPETITE
What is driving America’s Obesity Epidemic?
Are Americans too hungry?Do Americans have too big an
appetite?
HUNGER vs. APPETITEJames V. Neel• Thrifty Genotype
Hypothesis (1962)• Humans evolved in
environments of recurrent famine
• We are programmed to overeat when food is abundant
Regulation of Hunger-Satiety
HUNGER
SATIETY
EatStopEating
Regulation of Hunger-Satiety
Why do we overeat at buffet lines? Why overeat at Thanksgiving? Why eat dessert? Why won’t we eat horse or dog meat? etc.
HUNGER vs. APPETITE
Food has TWO types of values:Nutritive Value
Food provides us with energy, macro- & micro-nutrients
Symbolic Value
HUNGER APPETITE
Nutritive Values Symbolic Values
Energy needs Comfort
Macro-nutrients Entertainment
Micro-nutrients Money
Happiness
Luxury, etc.
Understanding Appetite in the Larger Context of Consumption
Based upon NEEDe.g. a wrist watch as
functional timepieceNeed is easily met
or satiated
Nutritive Value = Utility Value
Symbolic ValueBased upon DESIREe.g. a wrist watch as
a status symbolNo upper limit to
satietyOver-consumption
becomes possible
Understanding Appetite in the Larger Context of Consumption
If Wall St and Marketing can get us to buy bigger houses, more clothes, larger cars, and more gadgets than we need, is it possible they can get us to buy more food than we need?
Understanding Appetite in the Larger Context of Consumption
Understanding Appetite in the Larger Context of Consumption
Clearly, something happened to our consumption patterns around 1980
Understanding Appetite in the Larger Context of Consumption
Understanding Appetite in the Larger Context of Consumption
Understanding Appetite in the Larger Context of Consumption
Understanding Appetite in the Larger Context of Consumption
Understanding Appetite in the Larger Context of Consumption
It’s fine and good to talk about economic consumption, which isn’t regulated physiologically.
Wouldn’t our physiology protect us from food overconsumption
Isn’t our biology stronger than the culture of consumption?
SOCIOECONOMICS OF CLASS 3 OBESITY
Socioeconomics of Obesity
Why are the poor and less well educated so much more prone to morbid obesity?
Nutritious food is more expensive, fattening foods are cheaper
Drewnowski A, Darmon N. The economics of obesity: dietary energy density and energy cost. Am J Clin Nutr. 2005;82(1):S265-273.
BUT, the poor also consume more tobacco, tattoos, etc.
Sociology of Obesity
Pierre BourdieuDistinction: a Social Critique of the Judgment
of Taste, Taste (appetite) informed by our social classe.g. music, books, fashion, etc.
Our consumption is informed by our culturally defined tastes and preferences
Sociology of Obesity
Our class & culture informs our consumption of: Automobiles
Trucks vs. foreign imports Entertainment
Movies, TV programs, music Clothing Art Food/Drink
Can a culture of consumption alter our bodies permanently?
Tattoos, cosmetic surgery, body piercings, etc.
Can a culture of consumption alter our physiology?
Alcohol consumption and cirrhosisTobacco and emphysema
But body fat is regulated physiologically – can culture
override physiological regulation of body fat?
Anorexia – overrides profound hungerHunger strikes – override profound hungerBody builders – overrides minimum body fat requirements
Can Culture Make Obese?
YES Think of Sumo Wrestlers!
