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Meal timing

/ˈmiːl ˌtaɪ.mɪŋ/ · MEEL ty-ming noun phrase

Also: chrononutrition (scientific term), eating window

The timing, frequency and regularity of meals across the day. The scientific study of how meal timing interacts with the body's internal clock is called chrononutrition.

What it is and how it works

For a long time nutrition focused almost entirely on what and how much people eat. Meal timing adds a third question: when. It has gained attention because the body runs on a roughly 24-hour internal clock, the circadian rhythm, and many digestive and metabolic processes follow that clock.

Light is the main signal that sets the master clock in the brain. Food acts as a secondary signal for clocks in the liver, gut and other organs. When meals arrive at irregular times, or very late at night, these clocks can drift out of step with one another, which is one reason shift work has been studied so closely.

Breakfast table with a bowl of porridge, a cup of tea and an apple in morning light
A breakfast table in morning light. A regular first meal is one way people anchor their day.

Common patterns and terms

  • Three meals a day: the traditional pattern in many countries, with or without snacks.
  • Grazing: small amounts eaten frequently throughout the day.
  • Eating window: the hours between the first and last food of the day.
  • Time-restricted eating: deliberately keeping all food within a set window, often 8 to 12 hours.
  • Intermittent fasting: an umbrella term for patterns that include longer periods without food, such as fasting on certain days.

What the evidence suggests

Several findings come up regularly, though research is still developing:

  • Eating most of the day's food earlier, and not very late at night, tends to fit better with the body clock than the reverse.
  • Very late, large meals can interfere with sleep for some people; see sleep hygiene.
  • Regular meal times seem to help many people manage hunger and avoid arriving at dinner very hungry; see satiety.
  • For time-restricted eating, controlled studies often find that results depend largely on how much people eat overall, not only on the timing.

Breakfast is a good example of how mixed the picture is. Some people feel better with it, others are not hungry until later. Skipping breakfast is not harmful in itself for healthy adults, though children and teenagers are usually encouraged to eat in the morning.

In everyday life

  • Find a rhythm that suits you and keep it fairly consistent, including at weekends.
  • Leave a gap before bed: two to three hours between the last main meal and sleep is a common suggestion.
  • Spread protein across meals instead of saving it for dinner.
  • Don't ignore real hunger to meet a schedule; regular does not mean rigid; see mindful eating.

Common confusions

"Eating after 8 pm turns food into fat." There is no clock-based switch. Late eating matters mainly because of what and how much is eaten, and its effects on sleep.

"Breakfast is the most important meal of the day." The slogan is older than the evidence. What suits one person may not suit another.

"Fasting is right for everyone." It is not. People with diabetes, those who are pregnant or breastfeeding, people taking certain medicines, and anyone with a history of disordered eating should talk to a qualified professional before trying fasting patterns.

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Added Oct 21, 2026 · Filed under Everyday habits