Food science isn't as confusing as it looks

A common complaint says that nutrition news has become a series of contradictory discoveries, where the report of a finding this week will be overturned by a different study next week.

That perception itself is a myth, according to expert opinion on The Daily Circuit Wednesday. In fact, the basics of nutrition science have stayed relatively stable.

"It is more consumerism and media and things of that nature that are trying to make things change," said Dianne Neumark-Sztainer of the University of Minnesota's School of Public Health. "Our basic advice has really stayed the same about eating close to the planet, eating fruits and vegetables, eating whole grains, avoiding highly processed foods, avoiding foods that are high in sugar. Eating foods that have a lot of nutrients for not so many calories."

Neumark-Sztainer and Nutrition CheckUp Founder Heather Mangieri took on several other myths that interfere with consumer understanding of nutrition science:

• Body Mass Index (BMI) is not a good measure of a person's health.
While BMI is not perfect, Mangieri said, "it does give you a general understanding" of a person's condition. "It's used as a screening tool in schools because it's ... the best thing that we have for school nurses to use to screen children for overweight and obesity, but it's not the only thing you can use."

Neumark-Sztainer added that BMI use in schools is problematic for other reasons. "We need to take this in the overall society in which we live, in which being overweight is considered to be something bad," she said. "Not only unhealthy, but something undesirable."

• Healthy foods are always expensive.
Although it is true that healthy foods can be spendy, there are ways to eat healthily on a budget. Neumark-Sztainer named foods that are "very, very inexpensive but are really healthy." Legumes, dried beans and dried peas, for example, can be cooked in soup or eaten in pasta for an inexpensive meal. Buying fruits and vegetables that are in season can keep costs lower, too, she said. Another way to save money is to resist buying soft drinks, cakes and cookies.

• Carbohydrates make us fat.
Carbohydrates are harmful in large portions. "Carbohydrates are inexpensive to serve at restaurants so it's easy for them to give too much," Mangieri explained. "It is a lot easier to overeat carbohydrates than it is to overeat proteins."

Neumark-Sztainer said she recommends "intuitive eating." She encourages people to pay attention to how they feel: "Am I full? Am I hungry? What do I feel like eating? How much do I need to eat? ... At the same time, we really need to be working on changing our external environment, the sizes of portions and the types of foods that are served."

Learn more about nutrition myths:

• Best Diets for Healthy Eating
Any diet should provide sufficient calories and not fall seriously short on important nutrients or entire food groups. (U.S. News & World Report)

• Teens' fad diets can lead to putting on weight later
Their findings, reported in the latest Journal of Adolescent Health, show that students who tried weight-loss strategies such as skipping meals or taking diet pills in 1999 and 2004 were likely to be heavier in 2009. Girls who tried these tactics gained 4.63 points in their body mass indexes (BMI) over the 10-year study period. Girls who didn't gained only 2.29 points. (Star Tribune)

• Busting 10 Diet Myths (Real Simple)