February 24, 2018
Last Updated:
January 25, 2021

Chrononutrition: The Importance of Meal Timing

What we eat plays a major role in our health, but when we eat may be just as important. It turns out that even if two people eat the exact same foods and number of calories, an individual who eats most of their calories later in the day may be more prone to weight gain than someone who eats bigger meals earlier in the day. We’ll explore why this can occur and how you can make the most of your ‘chronotype.’

What is chrononutrition

Chrononutrition is the study of how nutrition relates to your body’s circadian rhythm, the internal clock that governs the physical, mental, and emotional cycles of your body. Your circadian rhythm is most affected by light and darkness, and influences sleep, body temperature, hormones, and appetite.

Historically, humans ate during daylight hours and slept during nighttime hours, and their bodies would produce hormones to align with the needs of the particular time (e.g., producing melatonin at night and cortisol during the day). Modern living doesn’t always stick to the same schedule, and can throw this rhythm off.

Erratic eating habits, especially late-night eating, and altered sleep schedules can throw your circadian rhythout of whack. Even exposure to artificial light at night can affect it! Fortunately, the body is highly adaptable. If you’ve ever traveled across multiple time zones, the jet lag you experienced is the body’s attempt to readjust its rhythm to the new schedule.


Different people can have different chronotypes, commonly called an “internal clock.” This can be influenced by the same things that influence circadian rhythm, plus things like shift work, jet lag, and mood disorders. Determining your chronotype is the first step to figuring out if your eating and sleeping habits are working for you, or against you.

There are three chronotypes: morning type, evening type, and neither. Morning types are early risers, getting up with the sun and sleeping easily at night. Evening types find it harder to wake during the day, and are more productive in the evening and nighttime. Most people fall somewhere in between.

Knowing your chronotype may also help you track eating habits. A 2019 study looked at the connection between chronotype, diet, and cardiometabolic health. Researchers found that identifying with an evening chronotype is associated with a lower intake of fruits and vegetables and higher intake of energy drinks, alcoholic, sugary, and caffeinated beverages, as well as higher energy intake from fat.

Why does meal timing make such a difference?

When your circadian rhythm is thrown off for any reasonit can affect the part of your brain that controls many important functions, including your ability to produce digestive enzymes like amylase and pepsin, which are essential to nutrient absorptionIf these functions are interrupted, it affects your ability to properly break down food, and lead to you feeling hungry, even if you aren’t, which can lead to weight gain and other health issues.

Aligning your eating and sleeping habits to match up with your body’s natural tendencies is one way to honor your bio-individuality, or the specific dietary and lifestyle needs your body has. You may not even need to switch your diet (although quality is certainly important!) – simply adjust your meal times to support optimal metabolism and reduce the risk of weight gain and obesity-related conditions.

1. Plan a nutritious breakfast.

Many find themselves too busy to eat a significant breakfast and often grab something light on the go or wait until the next meal to eat. This often leads to eating more later in the day. Research shows that a higher-calorie breakfast and a lower-calorie dinner can help support weight loss and reduce the risk of metabolic syndrome.

For a filling and nutritious way to start your day, try avocado and a poached egg on a slice of whole-grain bread or oatmeal with pecans, coconut flakes, and berries.

2. Get on a regular sleeping schedule.

Sleeping during daylight hours and working during nighttime hours may impact metabolism, leading to a greater chance of putting on weight. In fact, because of this phenomenon, people who work the night shift may experience changes in weight, even if their diet stays the same.

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Regardless of your schedule, try to get about eight hours of sleep per day – even better if it’s around the same time every day. Create a calm and dark space where you can wind down and settle into a restful sleep.

3. Eat smaller portions in the evening and enjoy larger portions of nutritious foods earlier in the day.

Larger meals in the evening are customary in many cultures, but switching to a more substantial lunch and eating less in the evening may help support weight loss and improve insulin sensitivity, which means your body will have an easier time maintaining proper blood sugar levels.

Experiment with smaller portions and lightened-up options for dinner, like a nutritious soup, an omelet, or a veggie-based bowl, and eating more “dinner-sized” meals for lunch.

Frequency and fasting

Recommended frequency of meals varies from person to person, and should be determined by you and your doctor, as well as a nutritionist or dietitianAccording to The Big Breakfast Study, your largest meal should be breakfast, then lunch, then dinner - and these three meals should be your only meals of the day.

The study goes on to say that the gap in between meal times is almost as important as the meal times themselves. Spreading out meals allows for your digestive system to work most effectively at absorbing nutrients and balance your metabolism. The study demonstrated that the following eating/fasting cycle was the most effective:

  • Eat breakfast, then fasfor 4 to 5 hours
  • Eat lunch, then fast for 5 to 6 hours
  • Eat dinner, then fast for at least 12 hours before breakfast the next day

Fasting for too long in between meals and a constantly-changing meal schedule may also lead to weight gain. Just like with sleep, it’s important to maintain a regular eating schedule.

Benefits of chrononutrition

While there’s no evidence that chrononutrition can cure diseases, it’s proven to be a good tool in managing blood pressure and stabilizing blood sugar levels. Research has demonstrated the link between dysregulated glucose levels and circadian rhythm disturbances, increasing one’s risk for type 2 diabetes. The American Heart Assocation says that “intentional eating with mindful attention to the timing and frequency of eating occasions can lead to healthier lifestyle and cardiometabolic risk factor management.”

Working with your body

What’s most important is to listen to your body. Recognizing your hunger and fullness queues is the best way to figure out when to eat. Not hungry for breakfast first thing in the morningWait until you are ready for a meal, and make the most of it by loading up on fiber, fat, and protein (oatmeal with berries and a scoop of peanut butter can do the trick!). Feeling peckish at 3PM? Have a healthy snack to keep your energy levels up. Learning to time your meals based on your unique body will ultimately make you more cognizant of not just when you’re eating, but what you’re eating.

Interested in discovering more about bio-individuality, healthy eating, and how best to help your body find optimal well-being? Download our Curriculum Guide to learn more.


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