Think breakfast helps kick-start metabolism and boosts weight loss? These are widely believed myths not supported by evidence, scientists say. But breakfast does deserve high marks for increasing physical activity.
You’re wrong about breakfast. And so is everyone else. Despite years of hype, two new studies point to a startling conclusion: skipping breakfast doesn’t necessarily lead to weight gain. Nor does eating breakfast boost your metabolism, suppress appetite, or reduce overeating later in the day. But it still might be one of the most important meals of the day (more on that later).
“Our findings are a bit of a reality check,” said nutritionist Emily Dhurandhar, an assistant professor in the Department of Health Behavior at University of Alabama at Birmingham (UAB), lead author of one of the studies. “It’s a broader question we’re trying to answer. As a message interpreted by the general public, just recommending people eat breakfast is not sufficient.”
While years of observational research have shown associations between eating breakfast and being leaner, none of the studies reach the gold-standard level of evidence of showing causation—randomized controlled trials—to show that breakfast was indeed responsible for weight loss, says James O. Hill, a professor of pediatrics and medicine at the University of Colorado, Denver, and co-author on Dhurandhar’s study.
At last, gold-standard research on breakfast has arrived. And the findings subvert years of nutritional advice while highlighting one often underestimated and under-hyped benefit of the morning meal. Dhurandhar’s trial randomized 309 overweight or obese adults who were given healthy eating advice to two groups. One group ate breakfast and the other skipped. Both groups lost a little weight, but there was no greater weight loss in the breakfast eaters as compared to the skippers. The researchers are careful to note that the study was not a controlled feeding trial and the subjects were not told what to eat at breakfast.
Another smaller study, led by James Betts, a senior lecturer in nutrition from the University of Bath, randomized 33 lean adults to either eat or skip breakfast for six weeks. The study found no appreciable difference in metabolic or cardiovascular health markers. “It is commonly stated that breakfast kick-starts metabolism and/or reduces snacking, etc. We saw little or no evidence of these things,” Betts said.
Insofar as testing has gone, the evidence hasn’t boded well for breakfast. But it wasn’t all bad news, Betts said. His study was also one of the first to measure how a feeding pattern influenced physical activity levels throughout the day using combined heart rate and accelerometry (think: sophisticated wearable tech, not just pedometers).
Betts sums up the results: “Specifically, the breakfast group was much more physically active than the fasting group, with significant differences particularly noted during light-intensity activities during the morning.”
In this case, this was causal evidence (not just correlation) that breakfast gets people moving—good reason to keep enjoying the most important meal of the day.
Our near-sacred regard for “don’t skip breakfast” is one of the most fundamental but oversold nutritional guidelines, and as we’re now discovering, there are plenty of other flawed recommendations in the nutrition world. So the problem isn’t with breakfast. It’s with a failure of skepticism, says the study’s senior investigator whose previous work began the attack on the conventional thinking, David Allison, director of UAB’s Nutrition Obesity Research Center.
“This goes back to the idea that we need to be more skeptical—we as scientists, as journalists, we as public health officials,” Allison said. “These platitudes sound good. You tend to believe them, but some might not be true.”
The perpetuation of pro-breakfast bias could be said to come in part by lobbying and funding of research by food companies keen on selling breakfast cereals and packaged breakfast foods. But diet myths are also often spread through shoddy reporting and writing. And they frequently come from public figures at the intersection of health and pop-culture. Take this line from the polarizing celebrity surgeon Dr. Oz. His site reads, “The fact is, when you’re trying to lose body fat, you can’t skip breakfast…” and “Boost your metabolic rate by 25%.”
Don’t trust Dr. Oz? How about this line from the Mayo Clinic’s site, “In fact, skipping breakfast actually increases your risk of obesity” or this quote from a researcher on Yahoo! Health, “Skipping breakfast may lead to one or more risk factors, including obesity, high blood pressure, high cholesterol and diabetes, which may in turn lead to a heart attack over time.”
Not only is the Internet rife with this kind of language, but so too is the scientific literature, Allison points out. And it’s not always in research that has received food industry funding, he says. There’s what he calls “white hat bias” largely found in observational or short-term trials that also suggest breakfast produces beneficial effects on metabolism and satiety. But, once again, these types of studies cannot demonstrate causation. These limitations are rarely addressed in the research or in the media hype. Plus, not all breakfasts should be considered equal; the timing and nutritional content (think: sugary cereal versus eggs) are both key.
“It’s tempting to assume that if something shows promise in a short-term study, or if it has some aspect on insulin or fat metabolism, that we can extrapolate from these. But I think that it’s important that we test these things,” Dhurandhar said.
If there’s one underlying message these researchers are giving, it’s just this: beware oft-repeated diet advice not rooted in evidence. Additional vague platitudes that perhaps deserve equal attention are “eat everything in moderation” and “eat only when you’re hungry.”
As made clear with the rigorously designed tests on breakfast, our presumptions don’t always hold true. But breakfast now has one new thing going for it: increasing physical activity.
“Whether or not you have breakfast can dictate how much activity you engage in, which directly impacts energy balance but also holds implications for health via the independent benefits of living a more active lifestyle,” Betts said.