People looking to lose weight are advised to avoid late night snacking. Studies show that late night eating increases the risk of being obese.

Few studies have investigated why late night eating is linked to higher body weight. This is what the US study found.

Many of the mechanisms that favor weight gain were changed by eating four hours later than usual.

Eating earlier in the day is more beneficial for both appetite and body weight control.

Late eating

In order to conduct their study, the researchers had 16 people follow two different meal schedules.

Participants in the first protocol were required to eat their meals early in the day with the last mealConsuming approximately six hours and 40 minutes before night time.

The participants were required to eat all of their meals four hours later. They had lunch, dinner and an evening meal. Two and a half hours before sleep, their last meal was eaten.

The study was conducted in a controlled lab, which ensured that the participants in each group ate the same diet and had the same amount of time to eat.

The researchers looked at three different measures in order to understand how late eating affects the body.

  1. The influence of appetite,
  2. The impact of eating time on energy expenditure (calories burned), and
  3. Molecular changes from fat tissue.

Two methods were used to measure appetite. Participants were asked to rate their hunger throughout the day.

The second technique was to collect blood samples to look at leptin and ghrelin in participants' blood to see if they are regulating appetite.

During the third and sixth day of each trial, these hormones were assessed.

Direct calorimetry was used to assess the effect of meal timing on energy expenditure. The amount of carbon dioxide produced by a person is compared to the amount of oxygen they use.

Researchers can use this to estimate how many calories a person uses.

The researchers used fat tissue from the abdomen to look at how late night eating affects the way fat is stored. Half of the people agreed to it.

Compared to an early eating pattern, late eating increased subjective feelings of hunger and the ratio ofhunger hormones in the blood.

The number of calories burned after late eating decreased. Late eating can cause changes in the genes that promote fat storage.

The results show that late eating can lead to a number of changes in the body that can lead to weight gain.

Potential for weight gain

We don't fully understand why late night eating promotes weight gain, but this study shows that it's probably the result of many factors working together.

There is a theory about why we gain weight when we eat late. The brain controls the ebb and flow of hormones in the human body. Daylight and food intake are important to it.

Humans sleep when it's dark out and eat when it's daylight, so the time of eating is related to the rhythms of the body.

The way the body uses calories and stores fat could be disrupted by eating late. This link has only been seen in studies on animals.

More research is needed to understand whether these changes are only temporary and what effect long-term late night eating has on weight gain.

Some studies have shown that people who eat late in the evening gain weight more quickly.

Other large-scale studies have found that skipping breakfast, late night eating and shift work are linked to higher body weight and higher risk of diabetes.

A growing body of evidence shows the importance of meal timing when it comes to body weight.

People who are watching their weight may want to stop eating late night snacks and start eating earlier in the day.

Alex is a Personal Chair in Nutrition.

Under a Creative Commons license, this article is re-posted. The original article is worth a read.