When it comes to nutrition, a new study by the American Dietetic Association divides the population into three categories. A virtuous 38 percent fall into the “I’m Already Doing It” cohort, which means their diet is basically healthy. Thirty percent are in the “I Know I Should, But…” camp, cognizant of how they ought to eat but unable to make themselves do it. Then there’s the unrepentant “Don’t Bother Me” group, amounting to 32 percent of the population. Why do people overeat even when they know better? Restaurants are partly to blame, and not just when we dine out and feel compelled to eat every bite (see the chart). Influenced by the massive portions many restaurants now dish out, people have hazy notions of what constitutes a proper serving—i.e, “the amount recommended in consumer education materials such as the Food Guide Pyramid.” When consumers were asked to estimate some correct serving sizes, 68 percent overstated the amount of cooked vegetables, 55 percent the amount of pasta and 54 percent the amount of cooked lean meat the experts recommend. Of course, some home cooks outdo the restaurants. Although 44 percent said restaurant portions are larger than what they make at home, a gluttonous 30 percent said they’re smaller.