ENERGYINTAKE ENERGYEXPENDITURE 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) TEF protein > TEF fat > TEF sugar
What We Eat 100 Calories From Sugar 100 Calories From Fat 100 Calories From Protein == TO A BUNSEN BURNER: ~98 Calories From Sugar ~95 Calories From Fat ~70 Calories From Protein After Adjusting for TEF
What We Eat 100 Calories From Sugar 100 Calories From Fat 100 Calories From Protein = TO A BUNSEN BURNER: ~98 Calories From Sugar ~70 Calories From 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 Eat Corollary 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 : Hunger : A sensation resulting from lack of food A sensation resulting from lack of food A biological signal stimulating the consumption of food A biological signal stimulating the consumption of food Appetite Appetite A desire rather than need for food A desire rather than need for food Non-biological Non-biological
HUNGER vs. APPETITE Hunger Hunger 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 items Read 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? Are Americans too hungry? Do Americans have too big an appetite? Do Americans have too big an appetite?
HUNGER vs. APPETITE James 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 Eat Stop Eating
Regulation of Hunger-Satiety Why do we overeat at buffet lines? Why do we overeat at buffet lines? Why overeat at Thanksgiving? Why overeat at Thanksgiving? Why eat dessert? Why eat dessert? Why won’t we eat horse or dog meat? Why won’t we eat horse or dog meat? etc. etc.
HUNGER vs. APPETITE Food has TWO types of values: Nutritive Value Nutritive Value Food provides us with energy, macro- & micro-nutrients Food provides us with energy, macro- & micro-nutrients Symbolic Value Symbolic Value
HUNGERAPPETITE Nutritive ValuesSymbolic Values Energy needs Comfort Macro-nutrients Entertainment Micro-nutrients Money Happiness Luxury, etc.
Understanding Appetite in the Larger Context of Consumption Based upon NEED Based upon NEED e.g. a wrist watch as functional timepiece e.g. a wrist watch as functional timepiece Need is easily met or satiated Need is easily met or satiated Nutritive Value Nutritive Value = Utility Value Symbolic Value Based upon DESIRE Based upon DESIRE e.g. a wrist watch as a status symbol e.g. a wrist watch as a status symbol No upper limit to satiety No upper limit to satiety Over-consumption becomes possible Over-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
Clearly, something happened to our consumption patterns around 1980
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 Wouldn’t our physiology protect us from food overconsumption Isn’t our biology stronger than the culture of consumption? Isn’t our biology stronger than the culture of consumption?
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 Bourdieu Distinction: a Social Critique of the Judgment of Taste, Taste (appetite) informed by our social class e.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 cirrhosis Tobacco and emphysema
But body fat is regulated physiologically – can culture override physiological regulation of body fat? Anorexia – overrides profound hunger Hunger strikes – override profound hunger Body builders – overrides minimum body fat requirements
Can Culture Make Obese? YES Think of Sumo Wrestlers!