Eating Late Is Really Bad for You

By Temma Ehrenfeld  @temmaehrenfeld
June 28, 2016

Late meals and snacks are linked to weight gain, acid reflux, and even breast cancer.

You may have read that light coming into your eyes sets the body’s clock, technically known as our circadian rhythm. Fewer people know that when you eat food shifts the clocks in tissues in your liver, muscles, and fat. Human beings evolved to eat only during daylight, which lasted 12 hours much of the year in the African savanna. That meant we didn’t eat for 12 hours a day. Sticking as nearly as possible to that plan can help you stay healthier as well as thinner. 


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It’s a surprisingly bad idea to eat dinner late, eat a big bedtime snack, or eat in the middle of the night. It’s also good to eat more earlier in the day. You’ve heard the old saying, “eat breakfast like a king, lunch like a prince and dinner like a pauper.” But that’s not the American rhythm. We actually consume, on average, 10 percent more of our daily calories at dinner than lunch. 

Weight gain

In a 2013 study  of more than 420 overweight or obese people, those who ate their biggest meal of the day before 3 p.m. lost 22 pounds during a 20-week study, compared to 17 among people who ate a big dinner, even when they consumed the same amount of calories and slept and exercised the same amount of time. 

Studies with mice suggest that eating within a 12-hour window is best for maintaining a healthy weight. The mice at least could safely go off the routine on weekends, though you don’t want to go wild. For most days if you ate breakfast at 8 a.m., you wouldn’t eat after 8 p.m. When you eat late at night, you tend to eat more overall. Perhaps driven by hormone surges, we crave sweeter, starchier, saltier food at night, research suggests. In one study, night eaters ate about 300 more calories each day. Three years later, people who didn’t eat near bedtime had gained only 4 pounds, while night-eaters had put on 14. 

However, if you’re exercising and weight-training, some small studies have found that the right kind of bedtime snack may help you build muscle mass and feel less hungry in the morning: a 150-calorie protein shake. That research absolutely doesn’t justify a nightly bowl of ice-cream. 

Acid reflux 

As many as 40 percent of Americans suffer from gastroesophageal reflux disease, which causes heartburn, post-nasal drip, hoarseness, chronic throat clearing, coughing, and asthma — and leads us to spend more than $13 billion a year on prescriptions and OTC meds. This isn’t a minor problem; the number of people who get cancer of the esophagus has increased by about five times since the 1970s, and research suggests that common anti-reflux meds won’t help and may even increase your risk. 

Eating late in the day aggravates reflux, writes Jamie A. Koufman, MD, who specializes in voice disorders and acid reflux. “Many of my patients find that eating earlier alleviates their allergies, sinusitis, asthma, sleep apnea and diabetes symptoms,” he says.

Breast cancer 

Women with early-stage breast cancer can improve their prognosis by avoiding late eating, a 2016 study based on data on 2413 women found. Regularly going a chunk of hours without eating lowers inflammation and blood sugar levels, which are linked to breast cancer. The researchers found that women who ate breakfast less than 13 hours after their last meal of the day before had 36 percent higher risk of breast cancer recurrence. 


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April 09, 2020

Reviewed By:  

Janet O’Dell, RN