In 1977, the year before I was born, a Senate committee led by George McGovem published its landmark " Dietary Goals for the United States," urging Americans to eat less high-fat red meat, eggs and dairy and replace them with more calories from fruits, vegetables and especially carbohydrates. By 1980 that wisdom was codified. The US Department of Agriculture(USDA)issued its first dietary guidelines, and one of the primary directives was to avoid cholesterol(胆固醇)and fat of all sorts. The National Institutes of Health(NIH)recommended that all Americans over the age of 2 cut fat consumption, and that same year the government announced the results of a $ 150 million study, which had a clear message; Eat less fat and cholesterol to reduce your risk of a heart attack. The food industry—and American eating habits—jumped in step. Grocery shelves filled with "light" yogurts, low-fat microwave dinners, cheese-flavored crackers, cookies. Families like mine followed the advice; beef disappeared from the dinner plate, eggs were replaced at breakfast with cereal or yolk-free beaters, and whole milk almost wholly vanished. From 1977 to 2012, per capita consumption of those foods dropped while calories from supposedly healthy carbohydrates increased—no surprise, given that breads, cereals and pasta were at the base of the USDA food pyramid. The nation was embarking on a " vast nutritional experiment," as the skeptical president of the National Academy of Sciences, Philip Handler, put it in 1980. But with nearly a million Americans a year dropping dead from heart disease by the mid-"80s, it had to try something. Nearly four decades later, the results are in: the experiment was a failure. Americans cut the fat, but by almost every measure, they are sicker than ever. The prevalence of Type 2 diabetes in the US increased 166% from 1980 to 2012. Nearly 1 in 10 American adults has the disease, costing the country"s health care system $ 245 billion a year, and an estimated 86 million people are predia-betic. Deaths from heart disease have fallen—a fact that many experts attribute to better emergency care, less smoking and widespread use of cholesterol-controlling drugs like statins—but cardiovascular(心血管的)disease remains the country"s No. 1 killer. What can be inferred from the last paragraph

A. Dietary change has contributed little to America.
B. About ten percent of Americans are prediabetic.
C. The change of diet has killed many diseases.
D. America"s obesity rate is higher than before.