Nutrition
June 25, 2023
TLDR: The Science of Meal Timing for Optimal Health
Consistent meal timing is crucial for both physical and mental well-being. This article explores how regular eating patterns can:
Align with our body's natural circadian rhythms
Prevent extreme hunger and fullness
Support better nutrient intake and metabolism
Key takeaways:
Our bodies have internal clocks influenced by eating patterns
Regular meals help regulate hunger hormones and fullness cues
Eating breakfast is beneficial for metabolism and nutrient intake
A 10-14 hour eating window is recommended for most people
Consistency in meal timing is more important than dietary perfection
By establishing a consistent meal timing strategy, you can improve your overall health and relationship with food. Ready to optimize your eating schedule?
[Read full article for in-depth scientific explanations and references]
In our fast-paced society and changing work schedules, irregular meal patterns and skipping meals are common. Many people with disordered patterns of eating have unpredictable meal times. Focusing on “when to eat” can be one of the most accessible and fundamental steps toward eating in a way that supports both physical and mental health.
This article will explore how consistent meals can align with our natural biological clock, prevent experiencing the extremes of hunger and fullness, and provide us with the opportunity to nourish ourselves reliably.
Meal Timing and our Body Clock
From the flower that blooms in the morning to the nocturnal animal that forages at night, life on Earth has evolved in the context of the 24-hour light-dark cycle [1]. Given that we, too, are part of the natural world, our bodies also run on 24-hour cycles, otherwise known as “circadian rhythms.”
We have an internal timekeeper called the suprachiasmatic nucleus, or the “master clock,” located in the hypothalamus, which uses light cues from our environment to determine the time of the day [2]. Interestingly, almost every organ in our body also contains an internal clock, called peripheral clocks, which relays information to our master clock. Instead of light input, our peripheral clocks are largely influenced by our eating/fasting patterns [3,4].
If we eat consistently, our peripheral clock expects food at specific times [5]. One reason you feel hungry before your typical meal is that your peripheral clock anticipates you will eat soon and signals this to your digestive system to release hunger hormones, such as ghrelin [6].
Similarly, our hormones that signal fullness also sync with our typical meal times through our circadian rhythm [7]. Therefore disrupted eating patterns like late-night eating or meal skipping can cause peripheral clocks to become out of sync with our master clock, and this misalignment is related to an increased metabolic disorder risk [8–10].
Meal Timing and Hunger
Just like the urge to pee means you should go to the toilet, a dry mouth tells you to drink water, and heavy eyes tell you to sleep, hunger is our body’s signal for food.
A consistent meal schedule supports our ability to perceive our hunger and fullness cues. If we consistently skip meals or go long periods between eating, it can be difficult to become in tune with our body’s messages.
When your body is evenly fueled throughout the day, it doesn’t need to signal for help. This signal alerts us that one of the body’s primal needs has not been met and shows up as a growling stomach, a diminished ability to concentrate and think rationally, and other symptoms like weakness, dizziness, and nausea.
Our hunger levels are affected by the distribution of meals throughout the day. Investigators found that even if total energy content was the same, individuals assigned to eat only one meal per day compared to three meals per day experienced significantly higher hunger levels [11]. This is, in part, because when we eat, we experience the physical sensation of fullness due to the gastric stretch of food filling our stomach and the consequent release of hormones that signal satiety [12].
Importantly, extreme hunger can lead to extreme fullness because when a ravenously hungry person finally eats something, they are more likely to eat quickly and overeat and thus swing into an uncomfortable fullness.
Both the experience of extreme hunger and fullness can be avoided by creating consistency around eating times (preventing long periods between meals). Ultimately, regular meals make us feel calmer around food as our body knows its essential needs will not be deprived.
What About Fasting?
It’s been suggested that time-restricted feeding, or intermittent fasting, may benefit mental health by improving brain signaling, neurogenesis, and synaptic plasticity [13]. However, most studies showing the benefits of intermittent fasting on outcomes such as brain health and longevity are in animal models, which lack the context of contemporary society.
In both animals and humans, fasting can lead to binge eating, and for humans, can lead to an obsession with food, which is particularly important since that can lead to impairments in social functioning and emotional distress [14].
For this reason, Wise Mind Nutrition generally does not recommend intermittent fasting. However, we’re always open to helping you find the best path. Remember, there are differences between what works best in the short term versus what works best in the long term. We’re playing the long game here.
What about Intuitive Eating?
There are also approaches such as “intuitive eating” and “mindful eating,” which suggest that you should eat when you’re hungry, stop when you’re full, and not subscribe to any rules or external sources of information. We believe there’s great wisdom in this approach. However, it’s our experience that it takes time and deliberate effort for most people to achieve this outcome.
Furthermore, some people are less capable of relying solely on their innate guiding system, particularly when biological imbalances, a significant trauma history, or medications affect appetite. For this reason, we want you to start by building guiding principles and see where it takes you. You’ll eventually develop some intuition around your body and food.
Should I Eat Breakfast?
Yes! Starting the day with breakfast is particularly beneficial for four main reasons:
When we skip breakfast, we prolong our overnight fast. There is a build-up of ghrelin (the hunger hormone), potentially leading to a ravenous appetite. Breakfast skippers are likelier to overeat at their next meal and crave calorically dense foods throughout the day [15,16].
Eating breakfast helps us manage our blood glucose levels. Our bodies are most primed to process food in the morning as insulin sensitivity is highest [17]. On the other hand, evening and late-night meals are not processed as well as morning meals because insulin sensitivity is reduced due to the melatonin being released [5]. Individuals who skip breakfast are more likely to have poorer glucose control as they are more likely to eat later at night and have a poorer diet [18]. Eating regular meals is inversely related to insulin resistance [19].
Skipping breakfast is consistently associated with a higher cardiometabolic risk profile [8–10]. Investigators found that those who didn't eat meals regularly were significantly more likely to have metabolic syndrome than those who did [19]. Similarly, among adults, eating in the morning was linked to a reduced risk of metabolic syndrome [20].
Breakfast is an opportunity to replenish blood glucose from our overnight fast and to consume vital nutrients. American adults who skipped breakfast were significantly less likely to consume adequate nutrients like folate, calcium, iron, and various vitamins [18]. Adults who skipped breakfast were likelier to have the lowest daily consumption of recommended nutrient intake levels [21].
Meeting Our Body’s Needs
A consistent meal schedule safeguards your opportunities to meet your nutritional requirements. It is fascinating to consider that eating also ensures that beneficial bacteria that reside in your gut are provided with the food they need.
Our body requires a steady source of fuel. This is partly because our brains are continually using glucose, its preferred source of energy, consuming around 20-25% of our blood glucose and demanding it at higher rates when we’re concentrating [22]. Eating only one meal per day compared to three is associated with higher fasting glucose levels and impaired glucose tolerance [23]. Therefore, consistent meals mean replenished energy sources that support steady glucose control.
How do I Create a Meal Timing Strategy?
A meal timing strategy will help you distribute your meals and snacks evenly throughout the day. You can start by picking how many times you intend to eat daily. Choosing an eating frequency between 3-6 times can be a helpful guide. To avoid the extremes of hunger and fullness, avoid going without food for more than 4-5 hours.
Next, pick an ideal time frame (window) for consuming those meals and snacks. Please note that times are not intended to be exact but used as a rough guide. It can help to consider when you typically wake up and fall asleep to assist. A 10 to 14-hour window is a good place to start.
Once you pick a strategy, try eating on a schedule for a week without worrying about what you eat. Once you’re on a schedule and your body is learning to expect foods at certain times, you can begin considering the variety of food groups and the ‘’what to eat” part of your eating. Your meal timing strategy doesn’t need to be perfect or exact; it just needs to be more consistent.
Conclusion
Eating regularly at consistent times is essential for the functioning of our natural circadian rhythms. It helps us avoid the extremes of hunger and fullness. Furthermore, having a plan around your eating lets you consider how you want to nourish your body. Your plan around “when to eat” doesn't need to be perfect; it just needs to be consistent enough so you and your body will get the message that it is safe and can begin to heal. Are you here for it?
Blog Collaborator:
Misa Mojarrabi, Graduate Dietitian
References
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