In a busy life it’s easy to fall into the habit of skipping breakfast or eating dinner late. But there are reasons to avoid this pattern, with a new study showing over time it may be linked to harmful changes in cholesterol and triglycerides — fats that circulate in the blood known scientifically as lipids.
“Importantly, the study evaluates both the individual and combined effects of breakfast skipping and night eating — an area previously understudied,” says lead study author Xiang Gao, MD, PhD, a professor and dean at the Institute of Nutrition at Fudan University in Shanghai, China.
“I think this study lends some evidence that there probably is a negative impact on lipid profile from routinely skipping breakfast and eating late, especially if you have other risk factors for cardiovascular [heart] disease,” says John Bostrom, MD, an assistant professor of cardiology at the Boston University Chobanian and Avedisian School of Medicine, who was not involved in the research.
What the Study Found
During the study, the volunteers — none of whom had heart disease, cancer, or lipid issues at the start — completed dietary questionnaires around their morning and evening eating habits. Scientists checked participants’ blood lipid levels three times during the study period to determine any yearly changes in LDL “bad” cholesterol, along with HDL “good” cholesterol, total cholesterol, and triglycerides.
The research team found that people who frequently skipped breakfast and ate later at night experienced a modestly greater annual increase in LDL cholesterol levels (0.89 mg/dL), along with an increase in triglycerides and decrease in HDL cholesterol levels.
The link between these eating patterns and negative lipid changes was strongest in women, people who were overweight or had obesity, and those who were physically inactive.
Why Does Meal Timing Impact Your Cholesterol?
“The human body is more sensitive to insulin in the morning, more insulin resistant in the evening, and less tolerant to glucose in the evening,” says Bernard Srour, PharmD, PhD, a professor at the French Institute for Agriculture Environment and Food (INRAE) and the Sorbonne Paris Nord University in France. “The human body is made to anticipate big meals during day time, as humans are supposed to be diurnal mammals,” meaning we’ve evolved to be most active during daylight hours, as opposed to nocturnal animals.
Study Has Some Limitations
As the study authors note, this research has a few limitations, including that the participants’ eating behaviors were self-reported, which can introduce bias into the results.
Dr. Gao also notes that while the underlying biological mechanisms behind these eating patterns are universal in all humans, the study did focus on a Chinese population, so the impact may not be the same for people living in other parts of the world.
“Cultural and lifestyle habits might resynchronize biological clocks, so differences across populations are plausible,” says Srour.
In addition, Dr. Bostrom points out that the change in lipid profiles over time was fairly small. “It does seem hard to believe that less than 1 mg/dL difference in LDL would have a strong impact on outcomes,” he says.
What You Can Do to Be Mindful of Your Meal Timing and Heart Health
Though an occasional late dinner or skipped breakfast likely isn’t a big deal, experts say you’re better off not making it a habit.
“Eating in accordance with the biological day — starting early and finishing early in the day, and avoiding skipping breakfast and nighttime eating — can be good strategies to improve metabolic health,” Srour says. “Meal timing regularity between weekend and weekday is also an important factor that is currently being investigated.”
Gao offers these tips:
- Eat breakfast consistently within a few hours of waking.
- Avoid food two to three hours before bedtime.
- Try to eat at the same times every day.
- Aim for a little more exercise or movement following days when your eating schedule gets thrown off.
- Be intentional about following a healthy diet.
“I think in general, if you have known risk factors for heart disease, it always makes sense to pay attention to your diet and try to focus on a ‘heart healthy’ diet,” says Bostrom.
