This will answer why fast food causes obesity and why obesity is rising at such a fast rate among adults and especially among children.
Does fast food cause obesity? In some ways yes; it adds to the obesity problem in America and the rest of the world. It depends on just how much fast food a person eats. And studies show that people are eating too much fast food. These foods have a great deal of calories, fat and sodium, and all of those add up to gaining weight and leading to obesity in both kids and adults. The obesity statistics are alarming.
The Studies and Statistics
In 1960, adult obesity in the US was at 13.6%. In 2006, the number of obese was at 34%. In May 2009, the Centers For Disease Control (CDC) reported that 32% of American children were defined as being overweight, 16% were obese and 11% were extremely obese. The average American consumed 500 more calories per day in 2000 than in 1970. A pound is 3,500 calories. This is an extra pound per week the average American is eating.
Another study conducted between 1994 and 1996 by the USDA Agriculture Research Service of 6,212 children, ages between 4 and 19, found what should be obvious answers. Their conclusion was, the kids who ate the most fast food, ate more calories, more total fat, more total bad carbohydrates, more added sugars, more soda pop, fewer fruits and vegetables and less fiber. The studies' finding was that consumption of fast food by children has an adverse effect on dietary quality in ways that could increase the risk for obesity .
A study by the University of California found that ninth graders are at least 5.2% more likely to be obese if a fast food restaurant is within one-tenth of a mile from their school . A study of 6,200 children found that 30% of the children eat at a fast food restaurant on any given day. On the days they ate at a fast food restaurant, they consumed an additional 187 calories. This equates to 6 extra pounds per year .
From 1977 to 1996, the average American over the age of two, increased fast food consumption from 9.6% to 23.5%. People are now using fast food restaurants not only for dinner, but also breakfast, lunch and snacks. I remember when I was a kid in the early 1970s, eating at McDonalds was something of a treat, something not done even once a month let alone every day.
Gaining weight is taking in more calories than the amount of calories your body uses up. Over time this leads to gaining weight to the point of obesity as defined by your BMI (body mass index). Currently a BMI of 25 or greater defines being overweight. And a BMI of 30 or over defines obesity. Obesity doesn’t happen overnight, it adds up slowly. Losing weight cannot happen overnight either; it takes effort and time to lose weight.
Calories Add Up to Obesity
A common meal from McDonalds could be a quarter-pounder with cheese, large fries and a large coke. This meal would be 1320 calories and 450 calories from fat, 51 grams of fat, 15.5 grams of saturated fat and 1.5 grams of trans-fat. The cholesterol is 90 mg and 95 grams of sugar, mostly from the Coke. Some of these places have healthier choices, but I usually don’t see kids ordering a salad with a glass of orange juice.
Obesity and bad eating habits are starting at an early age, and these habits are continuing through adult life. And it isn’t only obesity that is on the rise. Clogged arteries and diabetes type II are now showing up in adolescents.
Fast Food and Bad Fats
The calories in these foods is bad enough when you consider that most people shouldn’t be eating more than 2,000 calories per day. The bad types of fat are saturated and trans fat, which are bad for your heart and health. Children eating this way are already on the road to heart disease at a very early age. It’s these bad types of fat that affect the cholesterol in your blood. Fructose corn syrup and palm oil are now thought to be a contributor to the obesity problem.
Soft drinks might be even worse for obesity than the fast foods. A recent study showed that 16.1% of five-year-old girls who drank one serving (8 ounces) or less per day were overweight. At age nine, 24.2% were overweight. Of those who drank two or more servings per day at age five, 38.5% were overweight and 53.9% were overweight at age 11 . For each serving of a soda pop consumed, the risk of obesity increased by 1.6 times.
There is something called food density, nutrient and energy density. This is the amount of nutrients for a given food per calories. Energy is calories, and fast food is very energy dense. Meaning fast food has more calories for the volume or amount of food and less nutrients. A small amount of a fast food has a lot of calories for what you are really eating. Nutrient dense would be food with a lot of nutrients for the amount of calories, which would be fruits, vegetables and foods with a lot of fiber.
Fast food is but one contributor to the rising rate of obesity. But it still comes down to making healthy choices. Kids aren’t going to make the healthy choice usually, and the fast foods are all around them, including right in their own school.
A great book on the subject of how fast food became an American staple is called “Fat Land” by Greg Critser, ISBN 0-618-16472--3.
© Copyright October 2009 Sam Montana
Body Mass Index calculator
The Differences in Fats
 Pediatrics. 2004 Jan;113(1 Pt 1):112-8 Bowman SA, Gortmaker SL, Ebbeling CB, Pereira MA, Ludwig DS. US Department of Agriculture, Agricultural Research Service, Beltsville, Maryland, USA.
 Bowman SA, 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.2003; 113 :112 –118
 Source: The American Journal of Clinical Nutrition Vol. 90, No. 4, 935-942, October 2009 “Beverage intake of girls at age 5 y predicts adiposity and weight status in childhood and adolescence” Authors: Laura M Fiorito, Michele Marini, Lori A Francis, Helen Smiciklas-Wright, and Leann L Birch.