Eating at This Time of Day May Increase Your Risk of Obesity, New Study Says


Being obese, defined as having a body mass index (BMI) of 30 or higher, is linked with an increased likelihood of life-threatening health conditions, including heart disease, diabetes, stroke, cancer, and more. Right now, 73 percent of Americans are considered either obese or overweight, and roughly half of Americans have tried to lose weight within the past 12 months. However, as anyone trying to shed some pounds can attest, it's never as simple as it seems. Maintaining a healthy diet doesn't simply come down to what you eat, but also how much and how often—and now, a new study indicates that what time you eat can have an impact, as well. Read on to learn why eating at one particular time of day could be putting you at increased risk of obesity, and how to make a healthier meal plan moving forward.

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Obesity has a few common causes, experts say.
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At its most basic level, weight management is all about balancing the calories you take in through food with the calories you expend through exercise. Eat more calories than you burn, and your weight will rise. Burn more than you eat, and your weight will fall. "This equation can be deceptively simple, though, because it doesn't account for the multitude of factors that affect what we eat, how much we exercise, and how our bodies process all this energy," say experts from Harvard University's T.H. Chan School of Public Health. "The causes of obesity are as varied as the people it affects," they write, noting that "heredity is not destiny" when it comes to weight and health.

In particular, these experts say that "prenatal and early life influences; poor diets; too much television watching; too little physical activity and sleep; and our food and physical activity environment," can all play a role in your likelihood of developing obesity.

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Eating at this time may increase your obesity risk.

A controlled study, published in the Oct. 4 issue of the journal Cell Metabolism, says eating later in the day can increase your risk of obesity.

"In this study, we asked, 'Does the time that we eat matter when everything else is kept consistent?'" Nina Vujovic, PhD, study author and researcher in the Medical Chronobiology Program in the Brigham's Division of Sleep and Circadian Disorders told Science Direct. "And we found that eating four hours later makes a significant difference for our hunger levels, the way we burn calories after we eat, and the way we store fat."

When you eat appears to affect key hunger hormones.

The study analyzed data collected from 16 subjects with a BMI considered either overweight or obese as they followed a pair of strictly scheduled meal plans. Though the diets in these two meal plans were identical in their nutritional content, participants were first instructed to eat at an earlier meal time, and later instructed to eat four hours after that initial time.

The participants self-reported their changes in appetite, and the researchers collected blood samples, measured their energy expenditure, took their body temperature, and collected samples of fat tissue to compare any changes in gene expression from one eating plan to the next. "The order of the protocols was randomized, and visits were separated by a washout period of three to 12 weeks," the study explains.

The team found that eating four hours later significantly impacted two appetite-regulating hormones in particular: leptin, which promotes satiety, and ghrelin, which promotes hunger. When subjects ate later in the day, they also burned calories more slowly and showed a gene expression more prone to fat growth. These findings suggest that in addition to eating a healthy, whole foods-based diet and exercising regularly, eating earlier in the day can also help decrease your risk of obesity.

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These lifestyle changes can help you lose weight safely.

According to the Centers for Disease Control and Prevention (CDC), even modest weight loss which reduces your weight by five to 10 percent is likely to improve your health by lowering your blood pressure, blood cholesterol, and blood sugars. Incremental changes to your weight can make a difference even if you are still categorized as overweight or obese.

However, it's best to avoid diets that promise a "quick fix" and instead work toward losing weight safely over time, the CDC says. "When you're trying to lose weight, it's natural to want it to happen very quickly. But people with gradual and steady weight loss (about 1 to 2 pounds per week) are more likely to keep the weight off," their experts write. For more information on how to lose weight safely, speak with your doctor or check out the CDC's guide to getting started shedding pounds.