With his Meal Education and Labeling Act of 2007, Phil Mendelson has positioned himself as the District’s culinary Ralph Nader, protecting consumers from greasy, salty, carb-heavy foods that will certainly doom us all in the end.

But as University of Southern* California professor of sociology Barry Glassner writes in his latest book, The Gospel of Food, no one knows for certain what causes us to get fat or whether even our porkiness will shave years off our lives. Food, Glassner notes, is an easy scapegoat, thanks to countless scientific studies that routinely contradict each other from one year to the next.

Glassner reviewed the vast amount of published literature on what causes obesity—-and the consequences that obesity can have on health—-and walked away with this conclusion:

It’s hard to deny the wisdom of relying upon nutritional scientists for some kinds of dietary guidance. If you don’t want scurvy, you’d better consume some vitamin C. If you’re planning to become pregnant, you need enough folic acid to protect your child against neural tube defects. If you’re suffering from iron-deficiency anemia, you are well advised to eat raisins, beans, liver, eggs, and other foods high in iron.

But deficiency disorders are very different from obesity, heart disease, cancer, and other chronic diseases that Walter Willet [author and professor of epidemiology and nutrition at the Harvard School of Public Health] and friends say we can thwart by eating their favored foods. Chronic diseases are caused, as we have seen, not by a missing nutrient, but by a complex interplay of genetics, stress, physical inactivity, and a host of other factors. Undoubtedly, diet plays a role, but science is ill-equipped to tell us how much of a role or which ballyhooed foods are ultimately the most healthful.

Stress over your food choices and food suppliers, in fact, can be one more factor that leads to obesity. Maybe we Americans should just learn to do what the French do: enjoy their food, no matter what’s in it.