Easy question: Is breakfast good for you?

You probably already know the answer.

Now here’s the interesting part: why?

Think about the answer that instantly comes to mind.  Chances are it’s something along the lines of “it’ll help control weight”, or “it’ll reduce your hunger throughout the day”, or maybe it’s something even fuzzier like “you need food to get your brain going.”

The correlation between eating breakfast and good health outcomes has been pointed out ad nauseam, but what’s surprising is when you look for causal mechanisms it’s surprisingly difficult to pin anything down.

Does breaking your night long fast with a meal improve your insulin sensitivity?  Does the fullness from a hearty breakfast cause you to eat less throughout the day?  Or is it something a little more “magical” that creates the effect due to the cultural and social influences that go into breakfast?

It’s really hard to say.  Breakfast probably helps people feel more full throughout the day, and it does seem to prime your brain to think more clearly throughout the day.  It’s why so many schools have made breakfast programs such a large priority.

But for every proposed explanation about breakfast there’s a surprising vacuum of conclusive research that makes you believe that it has to be true.

The picture gets even murkier when you think about the million and one different ways that breakfast takes place across the world.  Its composition is very different from one country to another, and there are a lot of “just-so” scenarios that have to make you think twice about whether or not eating breakfast in all scenarios is best for you.

Breakfast is good for us, but McDonalds is bad for us.  So are we helping or hurting ourselves when we swing through the drive through to pick up an Egg McMuffin on our way to work?

Do you have to eat breakfast everyday in order to get its benefits?  Is the effect different for people who are overweight?

It’s surprisingly hard to tell.

Breakfast and Caloric Intake

It’s commonly posited that eating breakfast helps you feel full, primes your metabolism, and therefore helps people eat less food throughout the day.  There are a lot of observational studies which suggest this is the case.

But these are mostly descriptive studies where people fill out surveys every couple of months and then crunched for correlations.  These can yield interesting results but have a hard time answering the question why this might be the case.

When you look at randomized clinical trials things start to look a little wacky.  For example a study recently published out of Cornell found that for healthy people skipping breakfast doesn’t lead to caloric overcompensation later in the day.

Another one found that a breakfast that was high in protein is much more likely to reduce eating later on in the day than one with white carbs like cereal and pastries, which have little effect.  None of this is meant to disprove conventional wisdom, but just to point out that when you crack open the issue in a granular way there become more and more exceptions to the rule.

Breakfast and Weight Loss

It’s well established that people who skip breakfast are much more likely to be overweight and have heart problems.  Of course that says nothing about what is causing what.  You’re more likely to find someone with an umbrella when its raining outside but you’d be a fool to think the umbrella itself had any effect on the weather.

In his book Uncontrolled, Jim Manzi wrote extensively about the difficulties in truly measuring causality in any system that has multiple moving parts.  Lots of news that gets broken for a new result usually can’t be repeated by other researchers.  Many times what people think they are measuring is actually a proxy for some other unexplained variable.

This happens in the health and nutrition world all the time, when sanctioned advice is created based on some canned piece of wisdom that’s later exposed as bullshit, or at least having much more caveats than was originally thought.

A good example is coffee and pregnancy.  For a long time it was thought that drinking coffee increased your chances of a miscarriage, but that turned out not to be true.  The real issue is that people who drink coffee are more likely to drink excessively, smoke cigarettes, and have more addictive, self-destructive habits in general.  The coffee had nothing to do with it, so long as you are drinking less than 8 cups a day.

Might the same thing be true for breakfast?  Maybe the regular breakfast eater is just more mindful about their health, hygiene, less likely to hit the bottle, and gets a little more sleep at night.  Or maybe not.

Again, if you look at cross-sectional studies which take a snapshot of a group of people at one particular point in time the picture seems pretty clear:  eating breakfast is good for weight loss.  But when you follow the same people over many years, or perform a randomized control trial things start to get a little weird.  Not enough to make you change your mind, but enough to make you think about when standard thinking might not be as true as you think.

A good example would be a paper published in the International Journal of Obesity in 2003 that found for people who are overweight continually skipping breakfast helped them lose weight, but this effect tapered off when you examined normal weight people.

A randomized control trial published in the American Journal of Clinical Nutrition in 1992 found another curious result:  people who typically skip breakfast lose weight when they start to eat it, and people who regularly eat breakfast lose weight when they start to skip it.  It’s the change in eating habits that makes the difference, not your day-to-day habit.

This idea has some cache, because it’s been shown elsewhere that adding variety to your routine is good for your health.

 True, But With Caveats

I’m not writing this article to be cute.  Eating breakfast is a good decision.   The tradition has been around since the written scribe so I can’t imagine it wouldn’t have survived this long if it wasn’t useful.

But of course things are true until they’re not true anymore.  I don’t doubt the conventional wisdom surrounding eating breakfast, but do wonder how the realities of modernity might modify it.

For example it was found in the Journal of Physiology that the benefits of eating breakfast were heightened when people exercised beforehand.  Digesting calories without work is a new phenomenon, so perhaps the “priming” effects of eating breakfast are only felt if you’ve put some work in beforehand.

And there is shockingly little known about how the composition of breakfast changes your physiology.  We know calories are not created equal.  If you eat 40g of carbohydrate from a sweet potato you’ll feel full and nourished and have a steady energy level from the slow release of glucose into the bloodstream.  If you get the same 40g from French fries you’ll probably get manic cravings.

Surely this modifies how we’d benefit from breakfast, no? From what I can find (which isn’t much), what’s been studied agrees with current knowledge about macronutrient variables and our endocrine system.  For example, one of the benefits of breakfast is that it triggers the release of a hormone called ghrelin that suppresses hunger, but this effect is nullified if the breakfast is high in sugar or fat.

The take home point is that eating breakfast is a good idea, but don’t be afraid to be a little selective in how you apply rules of thumb to your own routine.  If you’re genuinely not hungry in the morning there’s no need to force yourself to eat.  If your day-to-day routine works just fine with skipping a few meals in the morning, then go with it.  If your morning just doesn’t feel right without your scrambled eggs, then that works too.