The Time You Eat Could Reduce Your Risk of Heart Disease
People who want a healthy heart and a lower risk of cardiovascular problems should pay attention not only to what they eat but also when they eat, according to a warning from the American Heart Association (AHA).
This report comes after extensive evidence showing that meal timing matters when it comes to cardiovascular risk. Eating patterns among American adults have changed over the past 40 years. Based on data from the National Health and Nutrition Examination Survey (NHANES) from 1971 to 2010 (n = 62,298), women aged 20–74 reported a decrease in total energy intake (TEI) over 24 hours.
Similar trends were observed among men. The proportion of men and women reporting that they consumed all three meals in a day decreased during this period (from 73% to 59% for men, from 75% to 63% for women), reflecting changes in eating patterns rather than meal frequency.
Indeed, the traditional breakfast-lunch-dinner pattern was not consistently observed in a population of healthy adults who do not work in shifts. According to a 2021 study, the number of eating occasions—defined as consuming any food or beverage providing at least 5 kcal—was approximately 4.2 times per day.
This study indicates that adults in the U.S. are eating almost continuously. Since feeding and fasting influence “clock genes” that regulate all aspects of metabolism, meal timing may have serious implications for the development of cardiovascular disease (CVD), type 2 diabetes, and obesity, scientists warn.
How Meal Timing Affects Health
The body’s circadian rhythms are controlled by the central clock located in the suprachiasmatic nucleus of the hypothalamus, as well as by peripheral organ clocks. While the central clock is strongly influenced by light, peripheral clocks are also sensitive to food intake, and time-restricted eating can reset the central clock rhythms.
Therefore, both when we eat and what we eat can have cardiometabolic implications by influencing peripheral clocks, particularly in the liver.
Why Timing Matters
“Many organs in the body have their own ‘clocks,’” specialists explain, “and this can affect how we process food at different times of day and night.”
“For example, the body has a harder time processing glucose in the evening compared to earlier in the day,” said St-Onge, Associate Professor of Nutrition at Columbia University in New York.
This conclusion highlights what is already known—and not fully understood—about meal timing and heart health. However, it does not provide strict rules, such as “never eat after 8 p.m.” or “breakfast is mandatory for everyone.”
Experts suggest that people should distribute calories over a defined period of the day, rather than consuming large amounts at once or snacking continuously. Based on available evidence, the American Heart Association recommends consuming more calories earlier in the day. A longer fasting period in the evening is better for the body than eating late at night.
The Importance of Breakfast
Several older studies show that people who eat breakfast are generally healthier than those who skip it. They tend to have fewer weight issues, better blood pressure and cholesterol levels, and a lower risk of type 2 diabetes and heart disease, according to the AHA.
The challenge is that these studies cannot prove that breakfast itself is the cause of these advantages. Few studies have directly compared outcomes from encouraging people to eat breakfast. Based on existing evidence, breakfast does not appear to aid weight loss. Of course, if people who skip breakfast end up adding another meal later in the day, they may gain weight, specialists note.
However, some smaller studies suggest that breakfast can help regulate blood sugar and insulin levels. Hydration after a night of fasting is also important, according to AHA experts. Breakfast is crucial because it is difficult to obtain all the nutrients the body needs from only two meals a day, even with small snacks in between.
How Many Meals and Snacks Should We Eat?
This raises another question: is it better to eat just three meals per day, or to consume smaller portions multiple times a day?
On one hand, observational studies suggest that people who eat more frequently have a lower risk of obesity and better cholesterol levels.
On the other hand, the AHA notes that intervention studies changing meal frequency have not shown any clear effect. When total daily calories are consistent, meal frequency does not appear to influence body weight, HDL cholesterol, or other heart health markers.
Of course, there is no one-size-fits-all approach. For some people, grazing throughout the day works, as long as food choices are healthy and snacking does not extend late into the night.
Frequent eating may not be ideal for people with insulin resistance—a condition common in type 2 diabetes or prediabetes. Eating often prevents insulin levels from dropping as they should.
Mindful eating is also important. People often eat not out of hunger, but to cope with emotions. Ask yourself why you are eating—are you stressed, sad, or bored? Are you truly hungry right now?
Intermittent Fasting
Intermittent fasting has grown in popularity over the last decade, particularly in clinical studies. The two most common forms are alternate-day fasting and periodic fasting.
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Alternate-day fasting involves a “fasting day” consuming ≤25% of energy needs over 24 hours, alternating with a “feast day” when any food is allowed for 24 hours.
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Periodic fasting involves fasting 1–2 days per week while eating normally on the other 5–6 days.
Studies show that body weight can decrease by 3–8% over 3–24 weeks of intermittent fasting. For example, overweight participants lost 8% of their body weight over 8 weeks by consuming a 320–380 kcal shake instead of a meal on fasting days during an alternate-day fasting protocol.
The frequency of fasting days per week appears to influence weight loss. Participants lost weight faster in alternate-day fasting studies (3–4 fasting days/week) than in periodic fasting studies (1–2 fasting days/week). On average, alternate-day fasting reduces body weight by 0.75 kg/week, while periodic fasting reduces it by 0.25 kg/week.
Systolic and diastolic blood pressure decreased only in studies with intermittent fasting. Systolic pressure dropped 3–8% and diastolic 6–10% over 6–24 weeks. Participants generally had borderline prehypertension, suggesting these diets may prevent progression to hypertension.
Many people practicing time-restricted eating follow a 16:8 schedule—eating within an 8-hour window and fasting for the remaining 16 hours each day.
Previous research shows that time-restricted eating improves cardiometabolic measures like blood pressure, blood glucose, and cholesterol.
New Findings
However, a recent study indicates:
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People who restricted their meals to an 8-hour window had a 91% higher risk of death from cardiovascular disease.
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The increased risk was also observed in people diagnosed with heart disease or cancer.
