(Medical Xpress)—Adults generally don't know how many calories they should consume daily to maintain their current weight, according to a new University of Florida survey, but that may not be a bad thing.
That's because knowing one's calorie needs can be a double-edged sword, said Cassie Rowe, who worked on the survey as a graduate student and is now a study coordinator at UF's Institute of Food and Agricultural Sciences.
"On one hand, it may allow people to balance energy intake with physical activity to manage their weight," Rowe said. "On the other hand, I think most Americans get bogged down by the numbers. In this respect, knowing your calorie needs may lead to unnecessary stress surrounding counting calories."
Rowe said calorie postings on restaurant menu boards were an impetus for the study.
"Do people even know what they mean? Are they going to have any context?" Rowe said.
Researchers surveyed 978 people of varying heights and weights from a cross-section of demographic groups, mostly on the UF campus. The survey found that people of all body mass indexes underestimate their daily energy requirements. Graduate students in the master's dietetic internship program in UF's Department of Food Science and Human Nutrition conducted the survey as a class project for their professor, Bobbi Langkamp-Henken.
The survey, conducted in early 2011, is published in the current issue of the Journal of Nutrition Education and Behavior.
In the survey, respondents answered 10 questions, including their height, weight and level of exercise. Based on those answers, researchers calculated how many calories the respondents needed daily, said Lauren Headrick, who worked on the research and was the paper's lead author. She's now state coordinator for Florida's Farm to School Partnership.
"What was so interesting in our study is, people underestimated their needs across the board, showing a clear lack of knowledge surrounding calories," Headrick said.
Here's an example of the survey's results: Most people who need, for example, 2,000 calories a day, think they should only consume 1,500.
This finding gives dietitians pause, Langkamp-Henken said, because if people learn their actual caloric needs are higher than they thought, they might be tempted to eat more than they normally would.
On the nutrition facts panel of all food labels, the standard is 2,000 calories a day, although an individual's needs may be different, depending on their age, size and exercise habits.
To their surprise, researchers noted that people who are obese underestimated their caloric needs the most.
But Langkamp-Henken offers a possible explanation.
"If they underestimate how much they need, it's probably because they've tried dieting in the past and gotten discouraged and realize it takes a whole lot of restriction of your intake to lose some weight," she said.