Eating Late Primes Your Body For Weight Gain

Updated: Oct 27

Eating late at night may induce more weight gain, and recent research suggests why this may be the case.

People who are trying to reduce weight have been given the piece of advice to refrain from eating late-night snacks for a long time. It should come as no surprise given the abundance of studies that indicates eating late at night is linked to higher body weight as well as an increased risk of obesity.


However, until now, only a small handful of studies has truly studied the specific reasons why eating late at night is associated with increased body weight. This was the purpose of a recent study conducted in the United States. They discovered that eating four hours later than usual influenced a significant number of the physiological and molecular pathways that contribute to weight gain.


This study adds to other recent research that was released not too long ago and revealed that eating earlier in the day is more advantageous for both hunger control and maintaining a healthy body weight.


After midnight meal


In order for the researchers to gather the necessary data for their study, they had 16 volunteers adhere to two distinct meal regimens, each of which lasted for a total of six days.


Participants in the first protocol were instructed to consume all of their meals early in the day, with the final meal being consumed roughly six hours and forty minutes before bedtime. In the second protocol, participants were instructed to delay the consumption of all of their usual meals by roughly four hours. This meant that they did not consume breakfast but rather consumed lunch, dinner, and an evening meal instead. Their very last supper was eaten about two and a half hours before they went to bed.


The research was carried out in a laboratory setting, which allowed the researchers to ensure that all the participants in each group ingested the same food and that they evenly spaced out each of their meals with around four hours in between each of them.


In order to acquire a better understanding of how eating late affected the body, the researchers focused their attention primarily on three distinct metrics that are connected with weight gain.


The impact of having an appetite


The effect of when you eat on how much energy you expend (in terms of calories), as well as the chemical changes that occur in fat tissue. Two different methods were utilized in order to evaluate appetite. The first method consisted of having participants keep a journal of their hunger levels at various points during the day. The second method involved taking blood samples from the participants in order to analyze the levels of appetite-regulating hormones in their blood. These hormones include leptin, which makes us feel full, and ghrelin, which stimulates our hunger (which makes us feel hungry). During the third and sixth day of each study, hourly measurements of these hormones were taken over the course of a 24-hour period.


An approach known as "indirect calorimetry" was utilized for the purpose of determining how the time of meals impacts total daily energy expenditure. This determines how much oxygen a person consumes in addition to the amount of carbon dioxide that they exhale. Researchers are able to more accurately estimate the number of calories that are burned throughout a typical day thanks to this information.


The researchers performed a biopsy on fat tissue collected from the belly in order to investigate how eating late at night impacts the molecular level of how the body stores fat and how fat is distributed throughout the body. Only fifty percent of the participants shared this opinion.


Those participants who ate later in the evening reported feeling hungry the following day, which may have contributed to their excessive eating. 


The researchers discovered that a late eating pattern, in comparison to an early eating pattern, not only increased the participants' subjective feelings of hunger the following day, but it also increased the ratio of "hunger" hormones in the blood. This was the case despite the fact that the participants in both protocols consumed the same diet. A decrease in the quantity of calories that were expended the next day was another effect of eating late at night. Late eating was demonstrated to trigger molecular alterations that promote fat storage in the subjects who underwent the fat tissue biopsy.


These findings collectively suggest that eating late in the evening is associated with a range of physiologic and molecular shifts that, over time, could contribute to weight gain.


Possibility of gaining excess weight


Despite the fact that we do not have a complete understanding of all of the mechanisms that are responsible for why eating late at night leads to weight gain, this study demonstrates that it is probably the consequence of a number of factors working together.


One possible explanation for why eating late in the day leads to weight gain is that our circadian cycle is disrupted. The brain is responsible for regulating the circadian rhythm that occurs naturally in the human body. This cycle has an effect on the typical rise and fall of hormone levels. It is especially sensitive to the amount of sunlight and food that it consumes.


In humans, the time of eating is intimately connected to the 24-hour cycle known as the circadian rhythm. Generally speaking, we sleep when it is dark outside and eat when it is light outside. When we eat late at night, this may throw off the body's normal circadian cycle, which can cause disturbances to the way the body consumes calories and stores fat, as well as to the hunger signals that it sends out. However, this connection has thus far only been established through research conducted on animals.


Due to the fact that the new study was only carried out on a few participants and for a very brief period of time, additional research will be required to determine whether or not these shifts are only temporary, as well as what effect eating late at night for an extended period of time can have on the weight gain mechanisms. But what we do know from other types of research is that persons who have a pattern of eating late at night are also more likely to have trouble maintaining a healthy weight.


These patterns of eating have been linked to higher body weight and a greater risk of metabolic disorders, according to the findings of other large-scale studies that looked at the relationship between disturbances in meal timing on energy balance. Some examples of these disturbances include skipping breakfast, eating late at night, and working shift work (such as high blood pressure or type 2 diabetes).


This study contributes to the expanding body of information that demonstrates how crucial the timing of meals might be with regard to one's overall body weight. In the light of the results of this and other research, individuals who are concerned about their weight could find it beneficial to forgo the consumption of snacks late at night in favor of consuming the majority of their meals earlier in the day.