From an early age, we’ve been taught that “breakfast is the most important meal of the day”. We hear that eating first thing in the morning can help to control our weight, and can even help us shed unwanted pounds.

The perception of skipping breakfast as an unhealthy habit has made its way into mainstream culture – and yet, there is a lack of clear scientific evidence to support these perceptions. How did these statements catch on, and how do we determine the truth? One recently published article offered another perspective on the Big Breakfast Debate. Get caught up:

1. What we know, and where we’re confused

Despite research showing that skipping breakfast is linked to lower daily energy intake (e.g. fewer total calories), eating breakfast is still widely associated with weight management and has been promoted as a weight loss strategy. Why? The rationale is that people who skip breakfast may overcompensate by having higher-calorie meals and snacks later in the day, leading to weight gain. Some researchers also believe that breakfast skippers may choose foods with lower nutritional value. However, randomized controlled trials (RCTs), the gold standard for determining cause-and-effect relationships, have not shown any difference in body weight after short- or long-term interventions. In fact, one study found that people who skipped breakfast actually lost more weight than breakfast eaters. Despite evidence to the contrary, the media and some nutrition experts continue to state the merits of eating breakfast for weight loss.

The study “Within-person comparison of eating behaviors, time of eating, and dietary intake on days with and without breakfast: NHANES 2005-2010” authored by Ashima Kant and Barry Graubard, aimed to compare the food choices and overall dietary intake of individuals who ate breakfast versus those who skipped it.

2. Why is it so hard to answer a simple question?

Many of the studies examining the effect of breakfast skipping on body weight and dietary intake have used an observational design. That means participants were asked about their normal dietary habits without being told to change anything. Some of these studies found that people who skipped breakfast tended to have a higher body mass index (BMI) compared to those who ate breakfast. However, these studies only proved that there was an association between breakfast and body weight, without directly proving that skipping breakfast caused weight gain. Demonstrating that a dietary pattern can directly cause or prevent a certain effect can only be done through well-designed RCTs.

But, there’s a catch to those RCT studies on this question, too. RCTs often use a parallel design, where one group of individuals is instructed to eat breakfast and another group is told to skip it. The downside? This kind of study puts constraints on when, what, and how much food to consume, which doesn’t simulate the eating behaviors of the same people in their normal environment.

One method for getting around the limitations of both parallel design interventions and observational studies is to use a crossover study design. In a crossover study, the same person receives one or more different treatments. Then, researchers can compare that person’s results to each other. This eliminates any unbalanced characteristics of different study groups and any possible confounding variables.

3. So what’s the new information?

Kant and Graubard aimed to approximate a crossover study design in a more realistic setting. Researchers used data from the National Health and Nutrition Examination Survey (NHANES) data set, collected from 2005 to 2010. NHANES participants were asked about what they ate in the 24 hours before the survey and were asked again 3-10 days later. In total, 2,132 people reported eating breakfast in one of the 2 recalls and were selected for analysis in this study, since each individual’s eating behavior and food choices on a breakfast day could be compared to what they ate on a no-breakfast day. Intake of meals and snacks, time of day of eating occasions, and intakes of energy, macronutrients, and food groups were analyzed and compared between breakfast and no-breakfast days.

4. Survey says…

All respondents tended to eat more servings of fruit and whole grains, and women ate more dairy on the breakfast day. Not surprisingly, both men and women ate lunch earlier and tended to eat more calories mid-day when they skipped breakfast. They also tended to snack more often on the no-breakfast day.

BUT overall calorie intake was still lower on the breakfast-skipping day compared to the breakfast day, by an average of 217 calories – a decrease of about 10%. When taking all meals and snacks into account, skipping breakfast had no influence on overall food quality (assessed by content of macronutrients, fiber, and total sugars) – that is, even though breakfast eaters got more whole grains, fruit, and dairy in the morning, by the time the day was through, things had evened out by the end of the day 

5. Takeaway (and the disclaimer)

The results of Kant and Graubard’s study show that skipping breakfast was associated with a lower overall energy intake and similar food quality, compared to eating breakfast. These conclusions echo previous research that disputes the long-held assumption that eating breakfast can help with weight loss.

Overall, this study adds weight to the shifting consensus on the impact of breakfast on how many calories you eat, and therefore weight loss. However, despite its unique design approach, this study was not without limitations – self-reported dietary intake has long been a problematic, yet ubiquitous, method of dietary assessment, since people tend to inaccurately recall the foods and beverages they’ve consumed. In this case, the short timespan between recalls might help mitigate that impact. This study also didn’t consider other important reasons for eating breakfast, such as eliminating early morning hunger pangs and maintaining blood sugar control. And with our busy schedules, a healthy a.m. meal can ensure that we’re able to fit in all of the nutrients our bodies need to maintain optimal health. If you choose to skip breakfast, it’s important to be more conscious of nutrient intake in other meals to meet dietary requirements and add variety to your diet. Our advice? Consider the evidence of breakfast’s role in weight control with a more critical, balanced perspective.