Is dietary knowledge enough? Was Rome built in a day?

A new USDA ERS report asks the rhetorical question, "Is dietary knowledge enough?" The full title of the report is "Is Dietary Knowledge Enough? Hunger, Stress, and Other Roadblocks to Healthy Eating."

Of course, we all know that dietary knowledge is indeed not enough, or else many of use would be eating far more vegetables and fruits and far fewer cookies and $1 double cheeseburgers. But the report gives a much fuller examination of the issue, and points the finger at away from home eating as the downfall of many. From the report's summary:

When individuals extend the interval between meals or consume more of their food away from home, they are significantly more likely to consume more calories and more calories from solid fats, alcohol, and added sugars (discretionary calories) at each eating occasion. For example, going 5 hours between meals instead of 4 adds about 52 calories for someone on a diet of 2,000 calories per day; extending that interval from 4 to 6 hours would add about 91 calories to the meal. Going longer stretches between meals is also estimated to lower diet quality at each meal. The location at which someone makes his or her food choices and when these choices are made significantly affects what and how much is consumed. Not surprisingly, people are estimated to consume more calories when eating foods from a restaurant compared with foods prepared at home—about 107 more calories per meal. The model suggests that people who work more hours in a week—a proxy for time pressures—are also more influenced by the interval between meals than those who work fewer hours. As an individual who works more hours in a week goes longer between meals, he or she will choose a meal that is significantly higher in calories, higher in discretionary calories, and lower in diet quality. At 4 hours between meals, an individual who works 40 hours a week is estimated to eat about 20 percent more calories than someone who is not employed. At 8 hours between meals, the calorie discrepancy jumps to nearly 40 percent.
Our model shows that a situational change in caloric intake and diet quality is more pronounced among individuals who are less informed about diet and nutrition. A person with a knowledge score of 50 (from USDA’s Diet and Health Knowledge Survey) is estimated to increase per-meal caloric intake by about 28 percent when eating away from home, while a person whose score is 100 points is estimated to eat about only 12 percent more calories. As people change their dietary goals based on prevailing nutritional beliefs, situational factors like hunger and time pressures will continue to interfere with long-term health objectives. Making specific reference to such situations and suggesting ways to mitigate their effects should enhance the usefulness of educational campaigns designed to improve diet quality. For example, encouraging consumers to take more active control in limiting the interval between meals and choosing nutrient-dense snacks, such as fruits and vegetables, may help them better align their intentions to eat well with their actual behavior. Limiting intake of foods prepared away from home is also estimated to significantly decrease caloric consumption. Thus, another possibility would be to encourage individuals to plan ahead or seek out information about nutrient and caloric content of foods prepared away from home.

TK: The message: eat at home and don't wait so long between meals. Practical tips for consumers in their semi-serious quest to lose weight.