“Breakfast is the most important meal of the day” is a slogan a century old, and the trials don’t support it. What does someone who knows that do in the morning?
The Short Answer
They check in with their body and respond accordingly. If they’re hungry, they eat. If they’re not hungry, they don’t. They don’t eat breakfast because it’s “time” or because they’ve been told it’s mandatory. They’ve freed themselves from a marketing slogan and replaced it with something better: listening to their own hunger signals.
Something to Sit With
Tomorrow morning, don’t automatically eat.
Instead, wait. Notice when hunger actually arrives. It might be 8am. It might be 11am. It might not come until noon.
Whatever time it is, that’s when you’re hungry. That’s when you eat.
Learn More
The Slogan’s Age.
The phrase has been in circulation a long time: breakfast has been advocated as “the most important meal of the day” since 1917.[1] You will often see it pinned to a particular cereal advertising campaign; the date is sourced and the story is not. The phrase stuck because it was repeated, not because it was tested.
What the Science Actually Shows.
The research on breakfast is far more nuanced than the marketing suggests:
Observational studies that show breakfast benefits suffer from confounding: breakfast eaters tend to have other healthy habits.[1]
Randomized controlled trials point the other way, and the numbers are worth having, with the review’s own quality rating attached, because it matters both ways. A meta-analysis of thirteen trials found, in the seven that measured weight (486 people), that breakfast eaters weighed slightly more, not less (by about 0.44 kg) and, in the ten that measured intake, ate about 260 kcal a day more; the authors rate that evidence low in quality, with all thirteen trials at high or unclear risk of bias in at least one domain.[1] A 16-week trial of 309 people found recommending breakfast made no difference to weight loss, with self-reported compliance above 92% and no effect even after adjusting for it: by their own reports people followed the advice, and it didn’t matter.[1]
And the fear underneath the slogan has been measured directly. Skipping breakfast does not slow resting metabolism: RMR held within 8 to 11 kcal a day across six weeks, in lean and obese adults alike.[1]
The scientific case for mandatory breakfast is weak. The case for “eat when hungry, don’t eat when not hungry” is much stronger.
The Morning Hunger Question.
Here’s what’s interesting about morning: most people have been fasting for 10-14 hours (overnight sleep), yet many don’t feel particularly hungry upon waking.
Hunger follows a circadian rhythm that is independent of when you last ate, independent of time since waking, too. The biological trough is around 8am and the peak around 8pm, with a peak-to-trough swing of 17% in the twelve adults measured.[2] Morning is when hunger runs lowest, which is exactly when you have been told to eat.
If you’re not hungry at 7am despite having last eaten at 7pm the previous night, that’s normal. Your body isn’t in crisis. Your metabolism isn’t broken. You’re just not hungry.
What Someone Who Knows This Does.
They don’t automatically eat upon waking. Instead:
They assess. “Am I actually hungry, or is it just morning?” Genuine hunger is a physical sensation. Morning routine is a habit.
They’re comfortable waiting. If hunger arrives at 10am instead of 7am, they eat at 10am. They don’t eat at 7am “just in case” they get hungry later.
They don’t force food. Eating when not hungry to prevent later hunger often doesn’t even work, and it definitely adds calories that weren’t needed.
They let their body lead. Some mornings they’re hungry; some mornings they’re not. Both are fine. The body’s signals vary, and that’s normal.
They reject the guilt. They don’t feel like they’re “skipping” something important. They’re responding to their body. That’s not skipping; that’s listening.
The Identity Shift.
Someone who knows breakfast is optional has shifted their relationship with morning eating:
- From: “I should eat breakfast because it’s important”
- To: “I eat when I’m hungry, which may or may not be morning”
This is an identity shift. They’re not someone who skips breakfast (framing it as deprivation). They’re someone who eats according to hunger signals (framing it as attunement).
The Practical Benefits.
Treating breakfast as optional:
Extends the overnight fast. If you finish dinner at 7pm and don’t eat until 11am, you’ve fasted 16 hours with no effort: you slept through most of it.
Reduces daily eating occasions. On the account Fung’s book gives, fewer eating occasions means more time with insulin low, and he places the post-absorptive phase at six to twenty-four hours after a fast begins.[3]
Simplifies mornings. One less thing to prepare, eat, and clean up.
Builds confidence. Learning you can function well without breakfast builds confidence that hunger is manageable, not an emergency.
Further reading:
- Sievert K et al., “Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials”[4] — BMJ, 2019
- Dhurandhar EJ et al., “The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial”[5] — American Journal of Clinical Nutrition, 2014
- Betts JA et al., “The causal role of breakfast in energy balance and health: a systematic review”[6] — Proceedings of the Nutrition Society, 2016
- Cummings DE et al., “A preprandial rise in plasma ghrelin levels suggests a role in meal initiation in humans”[7] — Diabetes, 2001
Written by AI, directed and approved by me. How this is made →