Scientists Say Eating Later In The Day Makes You Hungrier

A new study found that eating later in the day actually increased hunger as the day moved on.

By Jennifer Hollohan | Published

This article is more than 2 years old

The fitness and nutrition worlds have hotly contested debates over breakfast. One quick Google search will provide you with staunch advocates for eating breakfast, as well as those against it. And recent news of a new study will likely only add fuel to that perpetual back and forth.

A group of researchers decided to explore just how the timing of your meals impacts your overall hunger levels. Their fascinating results got published in the journal Cell Metabolism on Tuesday. The lead author is Nina Vujović, who works at Boston’s Brigham and Women’s Hospital and focuses on sleep and circadian disorders.

The study itself was small. It only had 16 participants. But the study’s size allowed researchers to closely monitor the group to prevent additional factors from influencing the results.

And the question was simple. According to Vujović, that question is, “Does the time that we eat matter when everything else is kept consistent?” As it turns out, eating later in the day does have a direct impact on your body.

In fact, researchers found that eating just four hours later in the day doubles your chances of hunger. While they regularly measured appetite and hunger levels throughout the study, researchers also analyzed blood samples. And what they found was surprising.

In a news report on the study, CNN noted that “levels of leptin, a hormone which tells us when we feel full, were decreased for late eaters versus early eaters. In comparison, levels of the hormone ghrelin, which spikes our appetite, rose.” As a result, participants eating later in the day burned calories significantly slower than those who ate earlier.

This slowdown occurred due to a shift at the genetic level, which impacts how fat is stored or burned. However, due to the short-term nature of the study, it is unclear what the long-term implications would be. So, the research team believes additional work in this area is warranted.

Given the results, what does that mean from a practical standpoint? Well, first, it’s good news for breakfast fans. Based on the results of this small study, eating earlier in the day helps reduce hunger and stabilize fat metabolism. 

So, how early does this mean? They broke study participants down into two groups. One group ate at 8 am, 12 pm, and 4 pm, and the second ate at 12 pm, 4 pm, and 8 pm. Then, after a few weeks’ break, the two groups switched roles.

On the surface, this does, in fact, appear to support eating breakfast (or at least a meal earlier in the day). However, the study explicitly excluded interested participants with a history of doing shift work. The reason is that shift work inherently impacts our circadian rhythm, which, in turn, has a cascade effect on the entire body. 

Overall, this study is great news for researchers hoping to understand the factors influencing obesity. The director of the Medical Chronobiology Program in Brigham’s Division of Sleep and Circadian Disorders, Frank Scheer, praised the study.

He said, “While there have been other studies investigating why late eating associates with an increased risk for obesity, this may be the most well controlled, including strictly controlling the amount, composition and timing of meals, physical activity, sleep, room temperature, and light exposure.”