Breakfast is supposed to be the most important meal of the day. At least, that is what many of us have been told from a very young age.
At the same time, it is probably one of the easiest meals to skip.
You slept in. You’re running late. Maybe eating immediately after waking up simply isn’t your thing. Suddenly breakfast loses the competition against an extra twenty minutes in bed and you tell yourself you’ll grab something later.
I remember being pretty young when a friend confidently explained to me why breakfast was obviously the most important meal. Think about it, she said. If you eat a big breakfast, you have all day to use that energy. Who would want to start the day with an empty tank?
Honestly, it sounded plausible.
But even back then it made me wonder: does that mean skipping breakfast is actually bad for you?
So let’s look at what happens when researchers put that very familiar piece of advice to the test.
The Short Answer
Skipping breakfast isn’t automatically bad for you.
The research doesn’t show that everyone needs to eat breakfast to maintain a healthy weight or body composition.
However, there is another side to the story. People who regularly skip breakfast often have worse health outcomes in observational studies, including higher rates of overweight and cardiovascular problems.
The important word there is associated.
Those studies cannot always tell us whether skipping breakfast is causing the problem or whether breakfast skippers differ from breakfast eaters in other important ways.
So in plain English: If you don’t like breakfast, the evidence isn’t telling you to immediately overhaul your morning routine. Eating breakfast may have some benefits, but skipping it by itself doesn’t automatically make your lifestyle unhealthy.
What Does The Evidence Actually Say?
This is where things get interesting because different types of research give us slightly different answers.
When researchers actually randomized people to eat or skip breakfast, the idea that breakfast is essential for maintaining your weight became much less convincing.
A systematic review by Brown and colleagues pooled randomized studies comparing breakfast eating with skipping. There was no meaningful difference in body weight, BMI, body-fat percentage, fat mass, lean mass or waist circumference between the groups.
A newer 2023 review found something similar, although with an interesting twist. Across 11 trials, people assigned to skip breakfast actually lost a small amount more weight. At the same time, their LDL cholesterol increased by around 10 mg/dL. So skipping breakfast did not appear to cause weight gain, but that doesn’t necessarily mean it was beneficial for every measure of health either.
Then we get to the observational research.
A 2021 review looking at people over time found that those who skipped breakfast at least three days per week had an approximately 11% higher relative risk of becoming overweight or obese compared with people who skipped less frequently. However, the authors themselves described the overall evidence as minimal, and there was no clear difference in BMI change.
Longer-term cardiovascular studies also make breakfast skipping look less favourable. A review involving almost 200,000 adults found that regular breakfast skippers had higher rates of cardiovascular events or cardiovascular death, as well as higher all-cause mortality.
But again, these were observational studies. The researchers specifically cautioned that other differences between breakfast eaters and skippers may partly explain those results.
So we end up with a rather important distinction: People who skip breakfast often look less healthy in observational studies.
But when researchers directly tell people to eat or skip breakfast, some of those supposed disadvantages become much harder to find.
🔬 For the curious: Why do the studies seem to disagree?
Imagine researchers observe thousands of people and find that breakfast skippers are more likely to become overweight.
It would be tempting to conclude: Skipping breakfast causes weight gain.
But what if the people skipping breakfast are also more likely to smoke? Or sleep differently? What if their jobs involve shift work? Maybe their overall diet differs, they exercise less, or their socioeconomic circumstances are different.
Researchers can statistically adjust for many of these factors, but they can never guarantee that they’ve accounted for everything.
A randomized trial works differently. Researchers actively assign people to eat breakfast or skip it. That makes the groups more comparable and gives us a better chance of isolating breakfast itself. And interestingly, once researchers do that, the supposed weight-control advantage of eating breakfast becomes much less obvious.
That doesn’t mean the observational research is wrong.
It means “breakfast skippers tend to have worse outcomes” and “skipping breakfast itself causes those outcomes” are two different statements.
What Changes The Answer?
There are quite a few reasons not to treat this question as completely settled.
For one, many of the randomized breakfast studies are small and short. In the Brown review, trials lasted between only six days and sixteen weeks, and the studies differed considerably in what participants ate and even in how they defined breakfast.
The 2023 cardiovascular review only contained 11 eligible trials. Its authors also found that factors such as sex, health status, study duration and the type of breakfast could influence the results.
Population matters too. The long-term cardiovascular review included adults aged 40 and older from the United States and Japan. Meanwhile, a newer randomized pilot study looked at only 125 younger adults in Taiwan. That study found some potentially favourable effects from recommending daily breakfast, including a smaller increase in diastolic blood pressure and reductions in body fat among inactive participants, but it was still a relatively small pilot study.
And then there is the very obvious cultural problem: Breakfast isn’t the same meal everywhere.
Comparing somebody eating cereal in one country with somebody eating rice, eggs, bread, vegetables or absolutely nothing in another makes the apparently simple question of “breakfast versus no breakfast” surprisingly complicated.
What Does This Mean In Real Life?
If you naturally don’t feel hungry in the morning and regularly skip breakfast, the current evidence doesn’t give us a strong reason to say that you must change.
In randomized studies, breakfast skipping hasn’t reliably caused weight gain or worse body composition.
At the same time, I wouldn’t turn that into “skipping breakfast is healthier.”
Some research has found potentially unfavourable effects, particularly increased LDL cholesterol, while long-term observational studies repeatedly find associations between frequent breakfast skipping and poorer cardiovascular outcomes.
Your overall lifestyle probably matters considerably more than whether one specific meal happens at 8 a.m. Someone who skips breakfast but otherwise eats a balanced diet, exercises and takes care of their health is not necessarily comparable to the average breakfast skipper represented in an observational study.
Likewise, simply adding breakfast to an otherwise unhealthy lifestyle isn’t likely to transform somebody’s health overnight.
🕳️ 🐇 Rabbit Hole: What even “counts” as breakfast?
You would think researchers could at least agree on this part. They don’t.
Across breakfast studies, the definition can vary substantially. Some researchers define breakfast according to a particular time in the morning. Others base it on how soon someone eats after waking up, how many days per week they eat breakfast, or simply whether participants describe themselves as breakfast eaters.
In the 2024 randomized study, for example, eating breakfast meant having a meal within two hours of waking up. Other studies included in systematic reviews used different timings and definitions entirely.
This might sound like a tiny methodological detail, but it matters.
Someone who wakes up at 6 a.m. and eats at 9 a.m. could potentially be called a breakfast skipper under one definition and a breakfast eater under another.
So even science has occasionally had to stop and ask: Wait. What exactly is breakfast?
EVIDENCE VERDICT
We have a useful answer, but not a final one
How convincing is the evidence?
●●●○
Moderately convincing.
Does it change what we should do?
Probably not dramatically.
If eating breakfast works well for you, there is certainly no reason to stop. If you naturally skip it and otherwise maintain a healthy lifestyle, there also isn’t enough evidence here to tell you that you need to force yourself to eat first thing in the morning.
The Bottom Line
Breakfast may be an important meal for plenty of people. That doesn’t necessarily make it the most important meal of the day, and it certainly doesn’t mean everybody has to eat it.
Current research doesn’t show that skipping breakfast automatically causes weight gain or makes you unhealthy. At the same time, habitual breakfast skipping is associated with poorer outcomes in several long-term studies, particularly for cardiovascular health.
So the answer is less dramatic than the advice many of us grew up hearing: Breakfast can absolutely be part of a healthy lifestyle. Skipping it can be too.
What seems to matter most is everything else you’re doing around it.
References & Sources
View the studies behind this article
- Yu Junhui et al.
Effect of skipping breakfast on cardiovascular risk factors: a grade-assessed systematic review and meta-analysis of randomized controlled trials and prospective cohort studies.
Front Endocrinol (Lausanne). (2023)
[Read the Study] - Bohan Brown MM et al.
Eating versus skipping breakfast has no discernible effect on obesity-related anthropometric outcomes: a systematic review and meta-analysis.
F1000Res. (2020)
[Read the Study] - Wicherski J, Schlesinger S, Fischer F.
Association between Breakfast Skipping and Body Weight-A Systematic Review and Meta-Analysis of Observational Longitudinal Studies.
Nutrients. (2021)
[Read the Study] - Ofori-Asenso R, Owen AJ, Liew D.
Skipping Breakfast and the Risk of Cardiovascular Disease and Death: A Systematic Review of Prospective Cohort Studies in Primary Prevention Settings.
J Cardiovasc Dev Dis. (2019)
[Read the Study] - Chen, H. J., Tsai, Y. C., Hsu, Y. T., & Chu, J.
Effect of recommendations of breakfast and late-evening snack habits on body composition and blood pressure: A pilot randomized trial.
Chronobiology International (2024)
[Read the Study]
Written by A Dose of Proof
Health research can be fascinating — but the way it’s written often makes it much harder to understand than it needs to be.
A Dose of Proof is the voice behind After the Abstract, translating health research into clear, evidence-focused explanations that look beyond the headline — including what a study found, what it didn’t prove, and whether the results actually matter.
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