Doctors have spent decades telling people what to eat for breakfast. A new study is asking a different question, does it matter when you eat it. The answer researchers found was striking enough to make international headlines, and nuanced enough that the scientists themselves are warning against overreacting to it.....Read Full Details Here>>>
The Study Behind The Headlines
The research, published in the journal European Journal of Clinical Nutrition, followed 31,044 adults aged 40 and older who took part in America’s National Health and Nutrition Examination Survey between 1999 and 2018. Over a median follow up period of 8.6 years, researchers led by Wen Hu and senior author Zhilei Shan of Huazhong University of Science and Technology in Wuhan, China, tracked 7,129 deaths among participants and compared them against when each person reported eating their first and last meals of the day.
The pattern that emerged was consistent and got stronger the later breakfast was delayed. Compared with people who ate their first meal between 7am and 8am, those who first ate between 8am and 10am had a 10 percent higher risk of dying during the study period. For people who waited until 10am to noon, that risk rose to 19 percent. Those who did not eat anything until after noon faced a 29 percent higher risk of death from any cause.
Cardiovascular disease showed an even sharper pattern. People who ate their first meal after noon had a 46 per cent higher risk of dying from cardiovascular causes than the earliest breakfast group, according to the study. Using their statistical model, the researchers calculated that a person who consistently started eating late from around age 50 could expect, on average, a life expectancy roughly 2.46 years shorter than someone who started eating between 7 and 8am.
Dinner Timing Told A More Complicated Story
The timing of the last meal of the day also showed a link to mortality risk, but not a simple one. Compared with people who finished eating between 7pm and 8pm, those who stopped eating earlier, before 7pm, had a 13 percent higher risk of death. People who ate after midnight had a 27 percent higher risk. Rather than risk simply climbing the later someone ate, the researchers found what statisticians call a U-shaped relationship, with the lowest calculated risk sitting around 8pm.
The researchers were explicit that this does not mean everyone should force their last bite to precisely 8pm. People who stopped eating unusually early in the study tended to be older on average, ate less frequently overall, and were more likely to already have existing health conditions, any of which could explain part of their results independently of meal timing itself. The study also found that once first meal timing was accounted for, the total length of a person’s daily eating window showed no consistent relationship with mortality on its own, adding a genuine complication for popular advice built purely around counting fasting hours.
Why Timing Might Matter, According To The Science
The leading explanation researchers point to involves the body’s circadian rhythm, the internal clock that governs everything from hormone release to digestion. Eating is one of the strongest signals the body uses to synchronise that rhythm, and Shan told the science outlet ScienceAlert that meal timing functions as “an important cue for peripheral circadian rhythms.” A later first meal or late night eating, he said, “may contribute to circadian misalignment and metabolic disturbances, including impaired lipid and glucose metabolism.”
Animal studies support a plausible biological pathway, showing that when animals eat can independently affect fat storage, liver fat accumulation, and the internal clocks of organs well beyond the brain. Whether those same mechanisms explain the mortality patterns found in this specific study of human adults remains, in the researchers’ own words, unknown.
The Researchers’ Own Warning Deserves As Much Attention As The Headline Numbers
Shan and his co-authors were unusually direct about the limits of what their data can prove. The study is observational, meaning it can show that late eating and higher mortality risk moved together in this population, but it cannot prove that eating later actually caused the higher death rate. The reverse explanation remains entirely possible, people who already have health problems, poor sleep, irregular working hours, shift work schedules, or difficult socioeconomic circumstances may simply be more likely to eat later in the first place, for reasons that have nothing to do with the clock itself.
A further limitation involves how the data was collected. Each participant’s eating pattern was estimated from a single 24 hour dietary recall taken at one point during the study, not from years of tracked behaviour, meaning it may not reflect a person’s actual long term habits. Shan told ScienceAlert directly that “later eating should be interpreted as a potential risk marker, and possibly a modifiable behavior, rather than definitive evidence of a direct causal effect.” In comments reported by Gigazine, he added plainly that people should not drastically change their eating schedules based solely on these findings.
A Separate, Different Study On What You Eat, Not When
A second claim connected to this topic in early reporting, that women benefit more from high fat breakfasts while men do better with carbohydrate rich ones, does not actually come from Shan’s mortality study at all. It comes from an entirely separate piece of research published in October 2024 in the journal Computers in Biology and Medicine, led by applied mathematics researcher Stephanie Abo and senior investigator Anita Layton at the University of Waterloo in Canada.
That study did not track real people eating real meals over time. It used a mathematical model simulating how male and female metabolisms respond to high carbohydrate versus high fat meals after an overnight fast, built from existing physiological data on how the two sexes process fat and glucose differently. The model suggested women’s bodies rely more heavily on fat for energy after fasting, breaking down roughly 20 percent more fat in fatty tissue than men’s bodies do, while men’s metabolisms appeared better suited to processing a carbohydrate heavy breakfast. Layton described foods like a vegetable and egg omelette or chia pudding as fitting the fat forward pattern the model favoured for women, and oatmeal or a fruit and yoghurt bowl as fitting the carbohydrate pattern favoured for men. Because this is a modelling study rather than a clinical trial that actually fed people different breakfasts and measured outcomes, its conclusions carry a different, generally weaker kind of evidence than Shan’s cohort study, and the two findings should not be treated as pieces of the same research.
What This Might Mean Beyond The Numbers
Neither study is Nigeria specific, and both come from very different populations, an American cohort tracked over two decades and a Canadian mathematical model. But the underlying question, whether irregular eating schedules driven by work, commute times or economic pressure carry a hidden health cost, is not one Nigerian readers can dismiss as irrelevant. Shift workers, market traders who eat their first meal only once the morning rush has passed, and anyone whose schedule is shaped by long commutes across Lagos, Abuja or Port Harcourt traffic are precisely the kind of irregular eaters both the researchers and outside caution alike would want studied more directly before drawing firm conclusions.
For now, what the evidence actually supports is narrower than the headline numbers suggest, a real, statistically significant association between later first meals and higher mortality risk in one large, well conducted study, alongside an honest acknowledgement from the scientists who found it that the cause behind that association is not yet established. That is a meaningfully different claim from “eating breakfast late will kill you,” and readers deserve the more careful version.
