Why do we worry about fat, but not sugar?

"'Fat is bad, fat is bad, fat is bad' is pervasive in our culture," says Marianne Rizk. (Credit: Windell Oskay/Flickr)

Most people pay more attention to fat rather than sugar when deciding if a food is healthy, a recent study with women suggests.

In fact, even when women know a food is high in sugar, they don’t rely much on that information to judge its relative healthiness. Overall, women in two studies relied more on their perception of a food’s fat and fiber content than on its sugar and protein stats when deciding if it was good for them.

That could spell trouble in the long term, researchers say, given the weight- and health-related problems associated with excessive sugar intake—namely, obesity and Type 2 diabetes.

“‘Fat is bad, fat is bad, fat is bad’ is pervasive in our culture,” says Marianne Rizk, a graduate student in the psychological and brain sciences department at the University of Iowa.

“I wasn’t surprised that people would rely on the fat content in terms of the healthiness of a food—the more fat, the more unhealthy it is,” she says. “That seems to make sense. But that same reliance was not there for sugar.”

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The results could be a response to an aggressive national nutritional campaign espousing the dangers of too much fat in one’s diet, says Teresa Treat, associate professor of psychological and brain sciences. “Still, I too was surprised by the discrepancy between fat and sugar.”

Surprisingly little is known about women’s perceptions of the relative healthiness of food, Rizk says, even though those perceptions could influence what women decide to eat and might be related to eating disorders or weight-related problems.

So the researchers developed an assessment strategy in which a group of women looked at pictures of 104 different foods, including cake, carrots, broccoli, fried chicken, bananas, and gummy worms, and judged the healthiness of each food on a 200-point scale.

“We know the nutritional content of all the foods, so we are able to calculate how much each woman relies on different nutrients when judging food healthiness, such as fat, fiber, sugar, and protein,” Rizk says. “This allows us to get a sense of what healthiness ‘means’ to each woman.”

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For example, “food healthiness” might be tied strongly to the fat content of food for one woman, related to sugar content for another, and linked to both fiber and protein content for a third.

Across two studies—the first involving 263 undergraduate women and the second involving 169 community women—the researchers found that most participants relied more on fat than sugar when judging food healthiness. They also found women had a tendency to overestimate a food’s healthiness when both unhealthy and healthy nutrients were present—a spinach salad with rich dressing, for example.

A third study showed that college-age women could discriminate between various small-to-moderate portion sizes of unhealthy foods, such as candy and French fries, but struggled as the portion sizes increased. That studied involved 272 participants who were asked to judge the healthiness of 124 photographs of unhealthy foods of varying size.

Psychologists know that it is harder for people to perceive size as size increases, so the results aren’t wholly surprising, Treat says.

“So, people are pretty good at distinguishing between small and medium sizes of foods. hey are not very good at distinguishing between large and extra large.”

Future public health campaigns should highlight the significant influence of portion size and proper sugar and protein consumption, Treat says.

“What Marianne has shown is women’s perceptions of healthiness are indeed related to nutritional composition and also to portion size, but not nearly enough in both cases. Thus, we currently are developing educational programs designed to help consumers better understand the roles of nutritional composition and portion size in food healthiness.”

Source: University of Iowa