That Late-Night Snack May Be Worse Than You Think

Disrupting natural sleep and eating rhythms could lead to serious health problems

Woman Reaching Into FridgeMetabolic diseases such as diabetes occur when abnormal chemical reactions in your body disrupt the normal process of metabolism, which is how your body makes energy from the food you eat.

A study using mice aimed to find out whether obesity and metabolic diseases result from a high-fat diet or the disruption of the metabolic cycle.[1]

You see, mice that are fed a high-fat diet whenever they want eat frequently throughout the day and evening. This disrupts the normal feeding/fasting cycle that most mammals follow, and this disruption has been found to contribute to metabolic diseases. However, it remained unclear if it was this disruption alone that contributed to metabolic diseases, or if the high-fat diet had anything to do with it, as well.

So for 100 days, researchers subjected mice to a high-fat diet either whenever they wanted to eat or at certain times of the day (time-restricted feeding). After 100 days, the mice on the time-restricted feedings had improved metabolic and physiologic rhythms, which protected them from the other negative components of a high-fat diet.

In fact, researchers found that, even though both groups of mice consumed equivalent calories, “The time-restricted high-fat-fed mice showed significantly increased thermogenesis and improved rhythms in nutrient utilization, leading to reduced adiposity and liver steatosis, normal glucose tolerance, reduced serum cholesterol, increased bile acid production, and improved motor function.”

In other words, restricting the mice to feedings only at certain times of the day, rather than letting them eat throughout the day and night, lead to less obesity, reduced risk of diabetes, and better cholesterol levels, among other benefits. And this was all despite the fact that their diets were high in fat.

What Does This Mean For You?

As mammals, we are programmed by our circadian rhythms, meaning we have evolved to restrict our activities to mainly the daytime hours. By developing this innate rhythm, our bodies are accustomed to performing certain physiological processes during optimal times of the day.

One of those processes is our metabolism. The hormones involved with metabolism — insulin, leptin and ghrelin, to name a few — are strongly regulated by circadian oscillation. For example, leptin, which suppresses appetite and boosts metabolism, peaks during the sleep phase in humans. Its release depends on your keeping with your natural circadian rhythm.

Knowing this, you can imagine the havoc you would wreak on multiple body processes if you decided to forgo sleep one night and binge on pizza and ice cream in the overnight hours. If you continually did this, you’d likely encounter some problems with weight, which could lead to metabolic diseases such as diabetes.

So, the take-home message from this study is that one of the most important ways you can prevent obesity and metabolic diseases is by following your natural circadian rhythm when it comes to eating. Once you’ve finished dinner, stop eating or snacking for the rest of the night so that your metabolism can function at its peak.

And remember, even though the mice on time-restricted feedings experienced positive results while eating a high-fat diet, this is by no means an endorsement of bad nutrition. Overconsumption of sugar, fat and processed foods can contribute to a multitude of health problems, so try to keep your diet as clean and healthy as possible.


[1] Hatori M et al. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 2012 June 6;15(6):848-60.

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