Meal Timing - Does It Really Matter When We Eat?

Quotes like "breakfast is the most important meal of the day" and "don't eat past 8 p.m." are popular pieces of nutrition advice - but how true are they? In our busy and fast paced lives we often skip meals or eat at odd hours of the day, and that may, or may not, have an impact on our health. Add to the mix our genetics dictating whether we are an "early bird" or a "night owl" and you have a recipe for confusion. Tune in to find out the truth behind when you actually need to be eating your first and last bites of the day.

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Credit to MonoSheep for the theme music.

Transcript

Welcome to Nutrition Bites. The no nonsense podcast where you get the truth about food so you can eat what you want and be healthy. I’m your host Maggie and welcome to Episode 13 of this series! Today’s topic was inspired by my dedication to breakfast, and love of late night snacking. On the menu today, meal timing. 

There’s long been talk on the street, and by street I mean Youtube and Cosmo magazine, about the importance of when you should eat your meals - particularly breakfast and dinner. Most often the discussion is focused around weight loss, but other health promises get looped into this debate too. The popular phrase “don’t eat anything after 8 p.m.” has been swirling around for decades, and as someone who snacks at night like a squirrel prepping for hibernation - I so badly want this one to be a myth. And when it comes to breakfast, some people are perfectly content missing the meal while I am the self-appointed captain of  team “wake up and eat”.  As a kid I distinctly remember running to the kitchen as soon as I woke up so I could sit down to my meal of OJ and a plain white bagel with butter - the picky eater’s breakfast of champions. Often, the timing of when we eat our first and last bites of the day are guided by cultural and personal preferences, but are there any health effects to these differences? Let’s dig in. 

Breakfast gets its name because it is the meal of the day when you break your overnight fast. The International Breakfast Research Initiative, a hilariously specific research group, defines breakfast as a meal that is consumed within 2 - 3 hours of waking up. And for a long time, the quote “breakfast is the most important meal of the day” convinced me that breakfast was a meal that could not be missed. I so strongly believed in this quote that as a teen I would scorn my teammates for not eating before morning practice. I even remember telling them unverified facts like “you’re going to die 4 years earlier if you don’t eat in the morning”. Fortunately, I’ve since learned to be less of an asshole when it comes to other people’s eating preferences and to always double check my nutrition advice.

Speaking of, let’s get back into that famous breakfast quote. Where does it come from and is there any truth to it? Back in the mid 1800s James Jackson and John Harvey Kellogg wanted to increase sales of their newly invented breakfast food...corn flakes cereal. Yeah that’s right Kellogg’s corn flakes. So they coined this famous quote about the importance of breakfast in order to help convince the masses to never miss the meal. But it was only after the pork industry adopted it to help sell bacon did it really become a mainstream quote. Pork lobbyists got thousands of doctors to sign off on the health benefits of eating more protein in the morning and voila - breakfast became known as the most important meal of the day. 

And while once upon a time, everyone ate breakfast, the consumption of this meal has been on a steady decline. One stat shows that between 20 - 30% of US adults do not eat breakfast, and that number is increasing. But why? Well our lifestyles have radically shifted in the past century. Women with their fancy jobs no longer have time to make luxurious sit down meals for their husbands and families, and in general people’s schedules have become more packed - whether it’s squeezing in a gym session in the morning, or sleeping in because of late night activities. Also let’s not dismiss the fact that some people just aren’t hungry in the morning! More recently, Intermittent Fasting, covered in Episode 5, has gained in popularity, and skipping breakfast is one strategy used to extend an overnight fast. 

But despite the popularity, and valid reasons, for missing breakfast, there does seem to be a lot of evidence pointing towards the importance of this meal for our long-term health. Maybe Mr. Kellog was onto something after all? Multiple observational studies have shown that compared to breakfast-skippers, those who eat breakfast tend to maintain a healthier weight over time and are less likely to become obese. Daily breakfast eaters also tend to have lower cholesterol and blood pressure and are less likely to develop cardiovascular disease. And it’s a similar story for Diabetes. But, scientists don’t clearly understand why these associations exist. The short-term effects of eating breakfast vs. missing it are actually pretty neutral. So what’s going on here? 

Well one potential theory for all these long-term findings is a concept called reverse causation - meaning, it’s not that skipping breakfast causes obesity or other chronic diseases, but those who miss this meal generally lead less healthier lifestyles. For example, some research has shown that adults who skip breakfast are more likely to smoke cigarettes, drink alcohol, not exercise, consume more added sugar, and have a higher daily caloric intake than those who do eat breakfast. Socioeconomic status plays a role too. Regular breakfast consumers may have more regular working hours, like the 9 - 5 kind of job, and therefore be able to go to bed, wake up, and eat at more reasonable times than a shift worker. 

So while a lot of studies do associate eating breakfast with improved long-term health, the science is just not strong enough to suggest you absolutely need to eat it. Even the American Heart Association has stated that if you don’t normally eat breakfast, there’s no concrete evidence to suggest you should start. And health experts agree, it’s more important to evaluate what you are eating for your first bite of the day, rather than when you are eating it. Birthday cake flavoured doughnut cereal - which is a real thing and also some weird carbohydrate inception - is not necessarily the healthiest way to break your fast. In fact, it may be better to miss breakfast if this is your only option for food. The important thing is to listen to your hunger cues and eat when you feel the need. If you can function without breakfast, so be it! Whenever you take your first bite of the day, focus on making it nutritious and delicious. 

Now let’s move on to the last meal of the day: dinner, or supper if you want to be uber Canadian. The timing of dinner is a less controversial topic, but eating at night in general has landed in confusing territory. Not eating past an arbitrary time in the evening is used in Intermittent Fasting and has been suggested as a weight loss tactic. But the latter has been proven false by comparing cultures across the globe. For example, Spaniards are notorious for late night dinners, sometimes sitting down as late as 10 or 11 at night, but they’re not necessarily more heavy than an early dinner kind of nation. In fact, multiple observational studies conclude that eating in the evening does not influence your body weight. Just like with breakfast, what matters more is what you are eating rather than when you are eating it. But that’s easier said than done - especially at night. 

It’s no shocking revelation that by the time dinner rolls around we’re often fatigued and would rather order take out than spend time cooking a healthy homemade meal. We also tend to eat more impulsively as the day progresses, so when it comes to our preferences for dinner or a nighttime snack, we’re more likely to give in to our cravings for high fat and added sugar foods. And if you’re a snacker, like yours truly, we’re often not eating mindfully at night either. I know I tend to focus on the latest Netflix drama rather than how many times I’ve refilled the chip bowl, or who are we kidding, given it up and gone for the entire bag completely. All of these factors combined puts us in a situation where we’re more likely to choose less healthy foods, and overeat - two key reasons why some people associate night time eating with weight gain. 

Apart from body weight there are also other aspects of our health that have been proven affected by our evening food choices. Going to bed soon after eating anything increases your risk of acid reflux and heartburn. That’s because when you lay horizontally you lose the effect of gravity which helps keep the contents of your stomach in their rightful place. The official recommendation is to wait 2 - 3 hours after eating before lying down which unfortunately means no more in-bed Doritos after the bar. Another trigger for heartburn is high fat and heavy foods, which is even more annoying considering that pizza, poutine and shawarma are the most common options we have to choose from late at night. Someone tell Pepto Bismol if they truly want to ackle heartburn they should create a salad and smoothie chain catering to night owls. Eating high fat and heavy foods at night has also been associated with disturbing our sleep. In particular, increasing the time it takes to fall asleep and the amount of time spent lying restlessly awake in bed. So as delicious and tempting as our more impulsive nightly snacks and meals are, it truly is better to try and eat less food, and keep it a little lighter.  

But as simple as that suggestion sounds, it’s not that easy for everybody to make healthier adjustments to their nighttime eating routine. And that may be in part due to genetics. Circadian rhythms are physiological and mental changes our bodies undergo that follow an internal 24-hour cycle. The most well known circadian rhythm is the sleep-wake cycle, which dictates when you naturally feel sleepy and wake up. A “master clock” in the brain directs these rhythms, but these biological shifts are also heavily influenced by environmental cues like lightness and darkness, as well as our DNA. 

Research in this space is still pretty new, but studies are emerging that show when we live against our internal clocks, we’re more likely to develop metabolic diseases, like obesity and diabetes. Night shift workers are a prime example. By nature of their job, these workers are awake when they should normally be asleep, and consume most of their food during what is usually a fasting time for their body. So it’s not too surprising that night shift workers are much more likely to be overweight, and at a higher risk for developing chronic diseases. 

So how can we use this information to make better choices? Well, the population can be divided up into different chronotypes - which is a categorization to define whether you are more of an early bird or a night owl. I’m positive you already know which one you are. Those with the early chronotype go to bed and wake up earlier, are more focused in the morning and tend to begin getting fatigued in the early afternoon. Late chronotypes are the opposite. While much of the population has kind of an average chronotype there is a huge individual variability. And despite our early bird or late night owl status being set by our genes, it also does shift over time. We all start out as earlier chronotypes - I’m sure many parents can relate to the ungodly hours their small children wake up and are prepared to run a marathon. As we age into our teens we shift to become late chronotypes, with our peak night owl status occuring around age 19. Afterwards there’s a slow and steady reverse back to an earlier chronotype. So next time someone complains about how they can no longer rally late into the evening like they did in their early 20s, you now understand why this happens. It’s biology baby!

Recently scientists have begun to investigate how differences in our internal clocks may impact our body’s response to meals like breakfast and dinner. One association that has been made suggests earlier chronotypes are more likely to maintain a healthy weight if they eat breakfast. On the flip side, late chronotypes are more likely to be obese if they eat a lot of food within 2 hours of going to sleep. Kind of mean to the late chronotypes no? Genetically you’re more awake at night, but also punished for eating too late at night. Unfortunately, even more research has shown that the cards are stacked against night owls. Recent findings suggest that late chronotypes also tend to have more difficulty controlling the quantity of food they eat, and that they tend to consume higher-fat foods, and engage in less physical activity - all of which contributes to their generally higher risk of developing obesity, heart disease and diabetes. Damn you DNA! 

Other early research suggests that your chronotype may influence when you should be consuming your daily calories. Generally speaking, to avoid increasing the risk of developing obesity, early chronotypes should ensure that more than half of their daily calories are consumed before 4 p.m. And for night owls? Most calories should be consumed before 9 p.m. Piecing everything together, this makes sense. Early chronotypes are up earlier, and benefit from eating breakfast, and consuming at least half of their calories before the late afternoon. Late chronotypes can skip breakfast without consequence, but need to ensure they avoid high calorie and high-fat foods in the evening. But keep in mind that this quick summary, and most research on chronotypes and their influence on our metabolic health, is in very early stages - so don’t treat this as gospel, but as another piece of info to better understand how you can shift your eating habits in a healthier direction.

While our 21st century lifestyles have radically changed how often and when we eat, evidence is still emerging as to the importance of the timing of our first and last meals of the day. There does seem to be an association between those who eat breakfast and improved long-term health but not enough evidence to dictate you should eat this meal if you don’t feel like it. There’s also a strong consensus that eating a lot of high-fat or high calorie foods shortly before bed is not recommended for anyone. And while research on chronotypes is still fairly new, the lesson is to really just listen to your body and try to live by your internal clock - there’s no need to eat a meal just because it’s the culturally acceptable thing to do. But the biggest takeaway from today should be this: focus less on when you are eating your meals, and instead focus on the nutritional value and quantity of food that you do consume. Remember: you are what you eat, not when you eat it. 

That’s been the bite for today. Stay hungry.