Nutrition labels on food might actually be worsening Americans’ diets as people who make low-fat choices some of the time overcompensate by eating too much food at other times, a researcher said.
“There’s no question people are doing that,” said Richard Mattes, a nutrition professor at Purdue University.
Low-fat foods are presumed to be potentially beneficial for people trying to lose weight and cut the risk of disease. However, researchers have not adequately studied the implications of providing nutrition information, Mattes said.
He studied 17 men and women who were given a fixed meal at lunch, then asked to keep a record of what they ate the rest of the day. When they were told the lunch was a low-fat meal, they increased their consumption during the rest of the day, Mattes found. When told it was a normal lunch, they ate less during the rest of the day, though the content of the lunch didn’t change.
Barbara Rolls, a nutrition professor at Pennsylvania State University, did a separate study in which she varied the fat and calorie content of a yogurt snack given before lunch.
When she told people they were getting a low-fat snack, they increased what they ate at lunch.
The point of the studies is that the amount people eat is determined partly by their knowledge of their food, not simply by the body’s regulation of hunger and satiety.
Researchers do not know, however, whether people would continue to overcompensate for low-fat meals over the long term, Rolls said. “If subjects continue to get their information meal after meal, and day after day, would they start adjusting? We don’t know.”