(CNN) - "Eat breakfast!" nutrition experts have been telling us for decades. It revs your metabolism! It keeps you from overindulging at lunch! It helps you lose weight!
But a new study suggests the "most important meal of the day" may not be so important - at least for adults trying to lose weight.
Published Wednesday in the American Journal of Clinical Nutrition, the study found dieters who skipped breakfast lost just as much weight as dieters who ate breakfast regularly. The researchers concluded that while breakfast may have several health benefits, weight loss isn't one of them.
So where did breakfast get its cred?
So far, research has generally shown a link between skipping breakfast and the likelihood of being overweight, but it hasn't proven that skipping breakfast causes weight gain. "Previous studies have mostly demonstrated correlation, but not necessarily causation," lead study author Emily Dhurandhar said in a statement from the University of Alabama at Birmingham.
There is good observational evidence to support breakfast's place on the menu, says Michelle Cardel, a co-author of the study from the University of Colorado Denver. Nearly 80% of people on the National Weight Control Registry, a group of more than 4,000 people who have lost at least 30 pounds and kept it off, eat breakfast every day. Ninety percent of them eat breakfast at least 5 days a week.
Skip breakfast, lose weight? Not so fast
Researchers split 309 adults who were interested in losing weight into three groups.
One, the control group, received a USDA pamphlet titled "Let's Eat for the Health of It" that described good nutrition habits but did not mention breakfast. The second group received the same pamphlet and was instructed to eat breakfast before 10 a.m. every day. The third group received the pamphlet as well and was told to avoid consuming anything but water until 11 a.m.
Researchers followed the groups for 16 weeks and recorded their weight to show changes over the study period.
Of the 309 participants, 283 completed the study. All three groups lost the same amount of weight on average, showing researchers that eating breakfast (or not) had no significant effect.
"This should be a wake-up call for all of us to always ask for evidence about the recommendations we hear so widely offered," David Allison, director of the UAB Nutrition Obesity Research Center, said in a statement.
There were several limitations to this study that should be taken into account when viewing the results, Cardel says.
"The participants were able to choose what they ate every day," she said. "So at this point we cannot conclude anything about how much food you should eat at breakfast or what kinds of food you should eat."
The study authors did not measure participants' appetite, body fat or metabolism, which previous research has shown may be affected by breakfast eating. And the small study was only 16 weeks long, which may have been too short to see a significant effect.
Keith Kantor, a nutrition expert and author of "The Green Box League of Nutritious Justice," says eating breakfast is still a good idea. Doing so creates a routine, he says, and humans thrive on routine.
"Skipping meals... and eating at random times throughout the day requires more of a thought process," he said. "This allows more room for negative behaviors like skipping exercise or grabbing fast food due to lack of planning."
A healthy breakfast, Kantor says, consists of high-quality protein, heart-healthy fats and produce.
"More research needs to be conducted so that we can understand what kinds of foods should be eaten at breakfast... how quickly after waking should people eat breakfast, and how much should people be eating at breakfast," Cardel said.