The diet industry and fad diets might lead you to believe that there is a precise time of the day to eat your meals that is best or “healthiest.”

But for most of us, the time of the day we eat our meals is determined by myriad factors, like our work schedules, our hunger levels, the medications we take, and even the times our family, friends, and co-workers are free to share a meal.

The fluid nature of day-to-day life means that sticking to exact mealtimes every day is challenging — and some days, it just might not be possible. Plus, the best mealtimes for you may change or evolve throughout your life.

Nevertheless, this doesn’t mean that mealtimes don’t matter. In fact, research suggests that the time of the day we eat and the amount of time that elapses between meals may have profound effects on our health.

This article explores why mealtimes matter and how to choose the best mealtimes for your lifestyle.

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Though many of us tend to feel like what we eat has a greater impact than when we eat, it’s important to remember that our bodies digest food differently at various times of the day.

Many of these daily fluctuations are related to circadian rhythm, the cycle that moderates our sleep-wake patterns over 24 hours. In other words, it’s the body’s internal clock, and it reacts primarily to changes in light (1).

We usually think of circadian rhythms as affecting how tired or awake we feel, but they also influence other physical, mental, and behavioral processes in the body, including eating and digestion (2).

Conversely, mealtimes influence circadian rhythm. Thus, our eating habits and circadian rhythms constantly interact, though some scientists remain unsure as to exactly how much (3, 4, 5).

Still, researchers have found associations between circadian rhythm, mealtimes, weight status, and even insulin resistance, a hallmark of metabolic conditions like obesity and diabetes (6, 7, 8, 9).

In fact, repeated disruptions to normal circadian rhythms, such as those that happen when you travel between time zones or pull an all-nighter, may increase your risk of developing a metabolic condition (10, 11, 12, 13).

For example, a recent study of 31 police officers found that officers consumed more calories during night shifts than day shifts. Other studies have linked night shifts with irregular meal patterns, poorer diet quality, and an increase in metabolic risk factors (14, 15, 16, 17).

SUMMARY

Mealtimes and digestion interact with natural processes in the body, such as circadian rhythm. Timing meals and digestion in a way that avoids disruption of these other processes tends to yield better health outcomes.

Keeping a consistent meal schedule from day to day is linked to weight loss, an increase in energy, and a reduction in metabolic risk factors for chronic disease (18, 19).

Still, eating at the same time every day may not always be doable, so it’s best not to take a one-size-fits-all approach to mealtimes.

What’s more, individual genetics affect much of how our bodies regulate circadian rhythms that interact with mealtimes. Thus, there’s no single best mealtime schedule for everyone, and it may take some trial and error to discover the best mealtimes for you (20).

Here are some guidelines to keep in mind when scheduling your meals.

Breakfast

Taken literally, breakfast is the first meal of the day during which you break your overnight fast. Scientists still debate just how important the timing of that meal is.

Some people feel strongly about eating breakfast within the first few hours of rising, while others prefer to wait until later in the day when their appetites are higher to have their first meal. Each may have its own set of benefits.

A few studies found that skipping breakfast may affect diet quality. More specifically, skipping breakfast may lead to eating more calories during lunch — and less nutritious food overall — during the rest of the day (20, 21, 22, 23).

What’s more, consuming more calories during breakfast rather than later in the evening may benefit weight loss efforts (24, 25).

On the other hand, some research found that restricting the total number of hours in the day during which you eat — specifically to 12 hours or less — may also assist weight loss efforts and improve metabolic health overall (19, 26).

Keeping a limited meal window during the day is a type of intermittent fasting known as time-restricted eating.

Lunch

In addition to eating a regular breakfast meal, studies suggest that an earlier lunch may help people lose weight — though it’s important to note that individual genetic factors are also at play (27, 28, 29, 30).

Some newer research even suggests that an early lunch may contribute to a healthier microbiome, the collection of bacteria in the human gut and body that have significant effects on overall health (31, 32).

All in all, keeping the bulk of your calorie intake in earlier hours of the day by having an earlier breakfast and lunch may benefit weight loss and metabolic health (33).

Dinner

When it comes time for dinner, eating earlier in the evening and avoiding high calorie meals just before bedtime or throughout the night may support better health outcomes.

One study in 8,000 adults associated eating late at night with dyslipidemia, higher levels of fat in the blood and a risk factor for chronic disease. Others have linked a late dinner with changes in body fat, weight gain, and the body’s ability to digest sugar (34, 35, 36, 37).

These research findings often have to do with the hormone melatonin. Released at night, melatonin is one of the primary hormonal regulators of circadian rhythm and our sleep-wake cycles (38, 39).

As the body releases melatonin, it releases less insulin, which inhibits its ability to digest sugars like glucose. Thus, scheduling mealtimes too closely to when your body releases the hormone, especially late in the evening, is a risk factor for chronic disease (20, 26, 40).

SUMMARY

Each of us has a unique genetic profile and individual circumstances that dictate our daily schedule and help determine the best times to eat. However, some research shows that eating a majority of daily calories earlier in the day may be ideal.

The best times to eat before and after a workout depend on the type of exercise you plan to do.

A high intensity workout or an intense cardio session may require more precise meal timing. On the other hand, a leisurely activity like walking lends greater flexibility.

For pre-workout meals, eating an hour or two before you exercise helps fuel your muscles. Just remember to give your meal enough time to begin digesting before you start any high intensity activities (41, 42).

For post-workout meals, eating within 2 hours of finishing an activity may help replenish your energy stores and repair any muscle protein damage that occurred during the exercise (41).

Still, scientists have a lot to learn when it comes to exercise and mealtimes. For example, some recent research suggests that eating before a workout rather than afterward may benefit blood sugar control (43).

Other studies have found that some people may perform better during aerobic exercises like running while still in an early-morning state of fasting (44).

Research on this topic is still emerging and sometimes contradictory, and it may depend on personal factors like individual health and the type of workout. Thus, more studies are needed (45).

SUMMARY

Eating 1 to 2 hours before a workout and then again within 1 to 2 hours following exercise helps ensure that you’re both properly fueled beforehand and adequately refueled afterward.

Though the best mealtimes will ultimately vary from person to person, there are some general suggestions for timing meals.

Keep these three rules of thumb in mind when planning your mealtimes (26, 46):

  1. Eat earlier when possible. Many studies have linked earlier mealtimes to better health outcomes, compared with eating late at night.
  2. Limit your daily window of eating. Keeping your entire caloric intake for the day within a 12-hour time frame reduces the risk that digestion will interfere with your body’s circadian rhythm.
  3. Consider your circadian rhythm. Your body may not digest and process your meals as efficiently while it’s also releasing melatonin — specifically late in the evening or during the very early morning hours.

These guidelines may be useful when trying to decide upon a consistent meal routine to follow.

However, you’ll likely want to consider some individual factors as well, such as:

  • Health conditions. Many medications must be timed with meals and may dictate when you need to eat. Conditions like diabetes also require eating at certain times of the day to maintain proper blood sugar levels.
  • Your daily routine. We often time our meals around work schedules and personal obligations. That may mean eating earlier or later than you would ideally like to. In this case, maintaining consistency may still help limit disruptions to your circadian rhythm.
  • Type of meal. On days when you have no choice but to eat later in the evening, choosing small, nutrient-dense, yet simple meals can aid digestion and limit circadian rhythm disruptions.
  • Your instincts. Mealtimes will likely fluctuate from day to day. It’s important to trust your instincts and allow yourself to eat when you’re hungry, even if it’s at a different time of the day than you planned.
SUMMARY

The best times of day to eat will vary from person to person — and maybe even from day to day. Consider eating the bulk of your calories earlier in the day, and try to avoid eating within a few hours of bedtime.

Eating a majority of your calories earlier in the day and limiting how much you eat later in the evening or through the overnight hours may help your body digest your food more efficiently.

It may also reduce your risk of certain risk factors for metabolic conditions like diabetes and obesity.

However, there is no magic bullet when it comes to mealtimes. The right eating schedule for you may depend on many factors, including your daily routine, health conditions, and genetics.

Nevertheless, by keeping the fundamentals of mealtimes in mind while allowing yourself flexibility, you can feel confident about your meal schedule — no matter what obstacles the day throws your way.