Proving the obvious can sometimes seem like a waste of time.
On the other hand, what's painfully clear to some seems questionable to others; that's why experts perform research and pile evidence about seemingly evident truths, in a determined effort to gather facts. These facts can then influence perceptions and affect policies.
Fast food is a fine example. I think that many people believe fast food is the worst possible food to eat, but every once in a while I'm confronted with a nagging question: How do you know fast food's bad for you?
What's wrong with fast food?
So how do we know? Let's start with the ingredient list.
From a nutritional point of view, if we were to invent the worst diet ever -- one with a component list designed uniquely for unhealthy weight gain and cardiovascular and metabolic morbidity -- we'd be hard pressed to imagine one worse than the typical fast food regimen. Fast food is highly processed, has lots of saturated fats, hydrogenated fats and refined sugar, salt by the teaspoon, very little fiber, very few vegetables and fruit, and many additives driving the "great taste" that keeps us coming back for more and overeating.
Now let's go to the epidemiological evidence.
Morgan Spurlock famously gained 25 pounds and suffered physically and emotionally after eating exclusively at McDonald's for just one month in his excellent documentary Super Size Me -- but that's just anecdotal. The evidence comes from studying large populations and analyzing the findings in a statistical way. I'll mention just a few of these studies.
A prospective study in the prestigious scientific journal The Lancet followed more than 3,000 young adults for 15 years, and showed that those who ate at fast food restaurants more than twice a week gained an extra 10 pounds and had twice the incidence of insulin resistance (a risk factor for Type 2 diabetes) compared to those who ate fast food less than once a week. A study in the Journal of the American Dietetic Association showed that adults eating at fast-food restaurants consumed 205 more calories per day than those who don't eat fast food. Another study in the American Journal of Clinical Nutrition showed a connection between fast food and the risk of Type 2 diabetes: Women who ate burgers more than twice a week had an almost 60 percent higher risk of developing diabetes. And the list goes on and on.
Now, a new study in Public Health Nutrition offers a fresh assessment of the quality of fast food menus. This study compares the menus of the top five fast-food chains (Burger King, McDonald's, Subway, Taco Bell and Wendy's) to the recommendations of dietary guidelines, and scores the menu on a scale of 100 possible points.
"F" for Fail
How does this work? The components of the menu are compared in quantity to the nine major food groups in MyPyramid, so the fruit, vegetables, grains, milk, and meat on the menu get a score by how closely they match recommendations. Other components of the diet -- those items we strive to limit, such as saturated fat, salt and added sugar -- get higher marks for having a smaller quantity. For example, a diet or menu would get the full five possible veggie points if it had 1.1 cups of vegetables for every 1,000 calories, and zero points for having no veggies at all; it would get a full 10 points for having less than 7 percent of energy coming from saturated fat, and zero points if 15 percent of calories are from saturated fat. Everything in between gets a proportional intermediate score.
So how did fast food menus score? The full menus in all the chains studied scored lower than 50 out of 100. The scores for fruits, vegetables, whole grains and salt were particularly low.
If it's not shocking enough to see an under 50 score, it'll be illuminating to see how the chains got to their under 50: They scored high on total grains, meat and beans. That's because any hamburger served on a fluffy white bun scores a full 10 points for meat, and a full 5 for grain, but these food components are, of course, not the foods Americans have a hard time meeting
The researchers also looked specifically at kids' menus, and those did score 10 points higher on average. But the scores were still consistently low, and one has to remember that although healthier options do exist on the menu, most people go into a fast-food joint for hamburgers, French fries and soda, not for the salad and apple slices.
Fast food is rich in all the foods Americans struggle to eat less of, and poor in those they have a hard time eating enough of.
And that's one reason why we should eat fast food as infrequently as possible.
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