In others parts of the world the effect of fast food can be seen already. I remember 25 years ago people in Venezuela were lean and muscular. Their diet was based mainly on rice, beans and meat, which is not precisely nutrient optimal but at least obese people were not predominant. Twenty-five years later you can easily see how the majority of people are packing weight around their waists and thights. One indisputable difference between now and then is thea mazing increase in fast food resaturants franchises that have sprung up, especially in the last 15 years.
I know this is not a scientific study but I am sure there is a pretty good correlation-Perhaps a study could be done to prove that.
If you want scientific proof of what i am talking take a look at this new study The new study is titled "Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis" (1)
"By comparison with the average 15-year weight gain in participants with infrequent (less than once a week) fast-food restaurant use at baseline and follow-up, those with frequent (more than twice a week) visits to fast-food restaurants at baseline and follow-up gained an extra 4·5 kg of bodyweight and had a two-fold greater increase in insulin resistance"So if you look at a 30 year period and the trend continues then you are looking at a 20 pound increase in body weight, which will put many of the participants in the obese category. And this would be the result of comparing people who ate infrequently (less than once a week) to more than twice a week. I know people who eats almost everyday at fast food restaurants.
Want more proof? look at these fatcs (taken from USDA data):
a) Fast food was not a significant expenditure before 1960, after which it rapidly gained in popularity. Today, fast food accounts for 18 percent of total food expenditures.
b) In 1900 almost all food was cooked at home from scratch
c) 2010: roughly 50% of all food is consumed in either full-service or fast food restaurants
d) 2010: of the 50% consumed at home probably there is a lot of processed food too.