Most discussions on health and weight loss strongly focus on what we are eating.
Perhaps we are eating too many carbs or too much fat. Perhaps our overall calorie intake is too high or maybe we need to get more nutrients into our diets.
Without a doubt, what we eat is critical to our health and our weight loss.
But, it’s not the whole story.
This is why people often fall back to the question of how many meals a day.
That concept of meal frequency highlights the way that our eating patterns can also influence our weight and health.
However, the discussion also extends beyond meal frequency, to the topic of meal timing.
Even though they sound similar, these two concepts are different and they have different implications.
Of the two, meal timing may be the most relevant and I’m going to show you why it has so much significance.
Meal Frequency versus Meal Timing
In general, meal frequency and meal timing are related concepts.
After all, if you change how often you eat, the exact timing of your eating is going to change as well.
The first of these is this idea of meal frequency. Meal frequency focuses on how many meals a day people should be eating.
The most general approach is three, breakfast, lunch and dinner.
But, some people argue that this isn’t the best way of eating.
For example, many people feel that we should be eating six or more small meals a day. That concept is sometimes called grazing.
It’s based on the idea that if our bodies are always digesting then our metabolism will be higher, which will contribute to weight loss.
It sounds good in theory, but there isn’t much scientific support behind grazing (1).
In fact, research indicates that eating more frequently doesn’t even decrease hunger (2), which is ironic, as people often choose this eating pattern to reduce their hunger.
Additionally, grazing entirely ignores the fact that hunger can be beneficial.
One reason for this is a biological process, known as autophagy.
Realistically, the idea of grazing is basically a myth and it offers little advantage for weight loss.
At the opposite end of the spectrum is the idea of intermittent fasting.
There are a number of variations to the approach, but in general intermittent fasting involves going a period of time without eating (7).
For example, some intermittent fasters might only eat between noon and 8 pm at night.
So, they’re eating over an eight-hour period and that’s it.
Intermittent fasting always sounds incredibly challenging, but it actually isn’t.
For example, if you were only eating between noon and 8 pm, the simplest approach would be to simply skip breakfast.
For people doing intermittent fasting, the answer to how many meals a day is often two.
Effectively, they eat lunch and dinner.
The time restriction on when intermittent fasters eat also mean that they tend to have fewer snacks.
There are two key benefits of intermittent fasting.
The first is that you are hungry some of the time, which can help with biological processes, like autophagy.
In fact, researchers point out that our typical pattern of food consumption (3 daily meals plus snacks) is a biological anomaly.
This pattern is not commonly seen in animals and was not common in our evolutionary history either (8).
This may mean that our bodies are not well adjusted to this pattern of consumption – which may be why intermittent fasting can help with biological processes.
The second benefit is that you’re consuming fewer calories.
Now, if you ate a lot of food during that 8-hour period, you probably wouldn’t see all that many advantages.
That just makes sense.
After all, if you don’t eat breakfast and don’t have an increased meal size later, then you are likely to eat fewer calories.
Of course, the downside of intermittent fasting approaches is that you tend to be hungry.
As I’ve mentioned, this may be a good thing biologically.
However, being hungry is something that many people find difficult and as such, being hungry can make it harder for people to lose weight.
In general, the concept of meal frequency addresses the question of how many meals a day.
It’s also important to note that meal frequency is pretty individualistic. Realistically, that is true for just about any dietary pattern.
Our bodies respond differently to foods and eating patterns.
So, some people might find themselves losing weight through intermittent fasting while other people might find that the process has no effect on their weight or that it is just too hard to maintain.
Intermittent fasting and grazing are two examples of meal frequency strategies, and they’re a good illustration of the concept of meal frequency.
But, what about meal timing?
People often overlook the patterns of when they eat. Instead, they focus on what they eat and how often they eat.
Now, don’t get me wrong, what you eat is still extremely important.
In fact, I’d argue that what you eat is much more important than how often you eat or when you eat. After all, unhealthy food is never going to be good for you, regardless of when you eat it.
So, meal frequency refers to how often you eat in a day, but it doesn’t specify when you eat.
In contrast, meal timing is focused on when you eat.
For many people, meal timing is fairly predictable, especially if they are eating the typical three meals a day.
In many cases, this means that people eat breakfast when they get up, lunch somewhere between noon and 1 pm, and dinner at some point in the evening.
This does vary between individuals and is often related to a person’s work schedule.
But, those general patterns are pretty common.
This is even true for many people that skip breakfast, as they will often still eat lunch and dinner at a ‘normal’ time.
One common deviation in meal timing is people who eat late at night.
This might mean that they are eating dinner late, or that they are having a snack or small meal much later.
For many people, that pattern makes a lot of sense.
After all, the typical pattern of eating means that people often eat dinner around 5 pm or 6 pm. That makes sense if you go to bed fairly early, but if you consistently went to bed at midnight, eating your last meal at 6 pm would make you pretty hungry at bed time.
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The Significance of Meal Timing
The idea of meal frequency makes sense to a lot of people, but what about meal timing?
Why is the timing of our eating significant?
A lot of this comes down to our body clock and the way that some biological processes cycle (12).
In general, our bodies go through similar patterns from one day to the next. Often this means that we are getting up, eating and sleeping at a similar time each day.
A driving factor in this process is the circadian rhythm, sometimes referred to as your body clock.
The term circadian rhythm refers to how we respond to the passage of the sun and of the day. It’s part of the reason that we typically get tired at night and why we tend to get tired at the same time each day.
Research is beginning to show that there may be a connection between the rhythms in our body, our health, our weight and our eating.
Let’s start with a simple idea and an unexpected one.
There are actually clocks throughout our body (not literally, of course) (13).
What I mean is that different parts of our body keep rhythms and follow a daily cycle.
These rhythms can affect one another and they are also all affected by our ‘master’ clock. That master clock is the one we are all familiar with, the rhythm cued by the day and night cycle (14).
So, what does this all mean?
It means that if we eat at the wrong point in this cycle, we can confuse our bodies.
For example, late at night, your body is preparing for sleep and this is the signal that is present throughout your body.
But, if you choose to eat around this time, you just introduced a new signal.
After all, your body has to digest anything you eat, which includes releasing insulin. That may have an influence on the clock in the pancreas, effectively resetting it (15).
So then, you have competing time cues in your body, which may have detrimental impacts on our health.
Even though this field of research is fairly new, there is a range of research supporting its effectiveness.
For example, one study found that eating later had a negative influence on weight loss (16).
Another study indicated that unusual patterns of feeding could act to disrupt the circadian rhythm (17), potentially contributing to obesity.
At the same time, research has also illustrated that there are temporal cycles in the regulation of functions surrounding adipose tissue (18).
This provides a mechanism for how the timing of food intake could affect obesity.
This may be especially relevant for high-energy meals (19).
Meal Timing Approaches to Take
So, the timing of our meals can potentially influence our health and weight.
That’s great – but it’s not very useful unless we know how to take advantage of this timing and improve our health.
The key idea of meal timing is that our eating should be in line with the signals that our bodies give us, rather than the opposite.
The most significant aspect of this seems to be the time that you eat your main meal.
This may be because high energy meals have the most effect on cycles within the body (20).
For example, one study looked at a population in Spain, where the main meal is lunch.
In this study, the authors found that weight loss was initially similar between the groups. However, as the study progressed, the weight loss of the late eaters began to slow down.
The end result was that the people who ate their meals earlier lost more weight overall (21).
Another study indicated that people with a high-calorie breakfast lost more weight than those with a high-calorie meal (22).
That particular outcome may be the result of a combination of factors.
In contrast, a high-calorie dinner does not have this effect, as there is no subsequent eating for the dinner to influence.
At the same time, a high-calorie dinner is likely to have different effects on the cycles in our bodies than a high-calorie breakfast would.
Indeed, research has also shown that the timing of our meals affects our hunger hormones, such as our levels of ghrelin, along with our sense of hunger in general (23).
This can be significant for weight loss as our sense of hunger and our craving for food is one of the reasons that many people cannot effectively stick to diets.
On an Individual Level
We don’t really know the implications of meal timing on an individual level.
Likewise, people vary in their natural sleep/wake patterns and those patterns typically change as people age.
So, for one person, eating dinner at 7 pm might be late while for another person this might be the normal dinner time.
In a similar manner, people vary considerably in what time they go to bed. Some might go to bed at 9 pm (especially if they start work early the next day) while for others a midnight bedtime is not unusual.
In many cases, the pattern of a person’s life is also outside of their natural circadian rhythm.
This could also affect how their body responds to various eating patterns.
For example, some of the studies mentioned earlier linked eating late with negative health outcomes.
But, what are the impacts if a person eats late at night when that is their normal pattern?
It’s very possible that the impacts are different.
After all, we know that people can adjust to different waking and sleeping patterns.
At the same time, keeping your eating habits to your body rhythm is not always easy.
For example, what happens if you are hungry at night?
Realistically, the relationship between sleep and food intake appears to work both ways (32), which can make it more difficult to figure out the best approaches for your health.
Overall, the idea is to find a balance between all of your different needs and your body clock.
Doing this can be difficult and for many people, it may not even be possible.
These complexities mean that much more research is needed concerning meal timing and its impact on health and obesity.
In the meantime, the best idea seems to be to try and fit in with your body’s rhythms as much as possible, while taking your other needs into account.
This reinforces the importance of paying attention to your own body and the way it responds to different things.
After all, the best options for how many meals a day and meal timing may well differ from one person to the next.
Limitations in Research
In some ways, the timing of meals is a challenging area to research.
For one thing, people vary in their living patterns and also show some variation in their natural sleep/wake cycle.
In fact, we’re beginning to learn that some people need 8 hours of sleep a night while others may only need 6 hours or some other amount. Likewise, many cultures sleep for a shorter period at night and nap during the day (33).
Another thing is that some studies look at the way people naturally space their meals.
For example, one of the studies I discussed above looked at people who categorized themselves as early or late eaters.
This may be an issue for research because a person who consistently eats late may be more likely to engage in unhealthy behaviors. For example, eating late at night often occurs because people are stressed or do not have the time to cook earlier.
In some cases, these patterns could also contribute to poorer quality meals.
Poor quality meals, and stress in general, certainly won’t help a person lose weight.
As a result, people who eat late may have behaviors and lifestyle factors that make weight loss difficult.
Clearly, this isn’t the case for everyone.
But, if people who eat late do, on average, have more unhealthy behaviors than those that don’t – this could dramatically skew the outcomes of research.
More experimental research is needed before we can fully understand the implications of meal timing.
Nevertheless, the research that we have seen suggests that the timing of our meals is more significant than most people assume.
Take Home Messages
Without a doubt, nutrition is complicated.
This topic highlights the importance of paying attention to when you eat in addition to what you eat.
In particular, you should try to avoid eating too late at night because doing so can mess with your internal rhythm.
This is particularly relevant for anyone actively trying to lose weight.
After all, weight loss is no easy task and many people struggle to lose weight and keep it off.
Nevertheless, what you eat is still the most significant component of weight loss and health.
So, don’t assume that simply changing the timing of your meals is going to make a dramatic difference in your weight.
Realistically, you need to be eating a healthy diet, getting enough exercise and watching your calorie intake. Those are the key components of being healthy and losing weight.
This is something the site LifeHacker points out as well. They suggest that when you eat can be a part of a weight loss strategy but it isn't nearly as important as what you eat.
Similarly, Precision Nutrition suggests that there is no one-size-fits all answer. Instead, the best solutions will vary depending on who you are, your biology and your behavioral patterns.
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