Evolution of the Obesity Epidemic Information from Time Magazine, National Geographic Magazine, and other sources
Exercise and Body Composition • Two major factors that lead to obesity: • Over-nutrition – consuming too much • Under-expenditure – expending too little energy
Over-nourishment • Increased caloric consumption • Increased portion sizes • Eating as entertainment
Exercise and Body Composition • Decreased daily energy expenditure • Transportation • Manual Labor • Entertainment
Role of Genetics • About 2/3rds of tendency for obesity is genetic • Factors include • Low RMR 15% • High RQ (low fat oxidation) 5% • Low spontaneous physical activity (fidgeting) 10% • Other??? • (Ravuzzin, ACSM, 2008)
Ancient History • Humans started by living in a world of scarcity. • To survive they developed the habit of eating everything that tasted good whenever they could find it.
Ancient History • That's the way it was during 99.9% of human evolution. • For most of the 7 million years of human existence, life has been "nasty, brutish, and short" • Thomas Hobbes
Ancient History • Life expectancy was under 30 years - mainly due to accidents, infection, childbirth, and predation.
Ancient History • Early diet consisted of fruits, shoots, nuts, tubers, and vegetation - all low in calories - took constant work and eating whatever we found just to stay alive. • Fruits were highly desirable so we learned to seek fructose and glucose.
Evolution • It was some 2.5 million years ago that our ancestors developed a taste for meat. • As a result, the human brain became markedly bigger and more complex at the same time. • We also increased in physical size.
Evolution • Because it's packed with nutrients and calories, meat gave early humans a respite from constant feeding. • Our ancestors ate a diet composed of lean meats, vegetables, and fruits and worked out almost nonstop.
Agriculture • 150,000 to 100,000 years ago. • Provided steady source of food. • No longer hunter/gatherers. • Farming became major source of food.
Agriculture • Nutritionally the shift away from wild meat, fruits and vegetables to a diet of mostly cultivated grains robbed humans of many of the essential amino acids. • Still physical exertion was common.
Environment • Our bodies evolved in an environment where food was scare and movement was required • We now find ourselves in an environment where food is abundant and movement is optional – recent development
Then and Now • In 1700, the average Briton consumed 7.5 pounds of sugar per year. • In the US, we currently consume 150 pounds of sweetener per year.
Overconsumption • Adult women are now eating 335 more calories per day than they did in 1971, while adult men have upped their intake by 168 calories.
Overconsumption • We each ate 1775 pounds of food in 2000, up from 1497 in 1970. • Although it appears we are eating more vegetables, almost 1/3 of these vegetables were iceberg lettuce, French fries, and potato chips.
Now • Rapid change in environment last 50 years compared to previous 50,000 years. • Removal of physical activity combined with abundance of food.
Now Daily imbalance is on average small: an extra can of soda per day (150 kcal) can add 15.6 pounds per year
Factors Related to Obesity • Food producers and the "Fast Food“ industry - if they’re successful, we all eat more
Childhood Obesity • The growth of the fast food industry and increasing portion sizes make it easy for children to overeat
Childhood Obesity • “A large fast food meal (double cheeseburger, French fries, soft drink, desert) could contain 2200 kcal, which… would require a full marathon to burn off” • Ebbeling CB, Pawlak DB, Ludwig DS. Childhood obesity: public health crisis, common sense cure. Lancet 2002;360:473-82.
Childhood Obesity • On days that children and youth eat fast food – they consume an extra 126 kcals/day (P<0.0001) • Bowman S, Gortmaker SL, Ebbeling CB, Pereira MA, Ludwig DS. Effects of fast food consumption on energy intake and diet quality among children in a national household survey. Pediatrics, in press.
Childhood Obesity • Sugar-sweetened beverages contribute to childhood obesity incidence
Childhood Obesity • “For each additional serving of sugar sweetened beverage consumed, both BMI (0.243 kg/m2; P=0.03), and incidence of obesity (odds ratio 1.60; P=0.02) increased.” • Ludwig DS, Peterson KE, Gortmaker SL. Lancet 2001, 357:505-8
Childhood Obesity • Television and video/film production and distribution industry - if they’re successful we all watch more
Now • Advertisers constantly telling us to "eat this now". • Obesity increases as industrialization increases.
A Widening Problem • In a historical first, there are now as many overnourished people as undernourished around the world.
Why are we fatter? • Here's the recipe for obesity on such a global scale: • Take technology—cars, washing machines, elevators—that reduces physical exertion. • Increase calorie consumption, courtesy of increasing prosperity.
A Widening Problem • Add television, computers and video games. • Stir in the intensive marketing of candy and fast food, and you have the makings of an epidemic.
A Widening Problem • In countries where the food supply has been unstable, people are getting fat despite far less abundance than in the United States.
A Widening Problem • The implication? • Newly industrialized nations in Asia, Africa, the Caribbean, and Latin America may develop even higher rates of obesity-related health problems than in the U.S.
A Widening Problem >24% 20-24 15-19 10-14 0-9 No data
A Widening Problem • North AmericaStates with the highest obesity rates—Mississippi and Alabama—are in the South. The more affluent and outdoorsy western states of Colorado and Utah have the lowest rates.South AmericaAs Latin America becomes more developed, supermarkets stocked with processed foods have become the norm, rising from 20 percent of food retail during the 1980s to 60 percent in 2000.
A Widening Problem • EuropeCandy, fast food, and sweetened cereals account for more than half the food ads in ten European Union nations. In the U.K. snack food consumption rose nearly 25 percent in five years.AfricaIn some parts of Africa obesity afflicts more children than malnutrition. In Tunisia the urban population is shifting from traditional healthy whole grain breads to white bread.
A Widening Problem • AsiaIn Shanghai, roads once filled with pedestrians and cyclists are now congested with cars. KFC opened a drive-through restaurant in Beijing in 2002, with more to come.OceaniaPacific Islanders have always valued hefty physiques. Now their shift away from local foods to a high-fat, Western diet has made them among the world's fattest people
Now • The Puget Sound ferries in Washington have increased the width of their seats from 18 to 20 inches to allow squeeze-in room for bigger bottoms.
Now • In Colorado, an ambulance company has retrofitted its vehicles with a winch and a plus-size compartment to handle patients weighing up to half a ton (1000 lbs).
Now • An Indiana manufacturer of caskets now offers a double-oversize model - 38 inches wide, compared with a standard 24 inches.
Discrimination • In one study at Michigan State University, undergraduates said they would be more inclined to marry an embezzler or cocaine user than an obese person.