Research reveals the health detriments of eating late

Snacking late at night reduces the body's ability to burn fat, just as you give in to a fatty fix. Photo / Getty Images

There is a well-known link between eating late and weight gain - now new findings suggest it also increases your risk of diabetes and heart disease, reported the Daily Mail.

A team of US researchers found eating later boosts glucose and insulin levels, which are implicated in diabetes.

Late-night meals also raise cholesterol and triglycerides, a type of fat in your blood, both of which can increase your risk of heart disease.

And in line with previous studies, the research discovered late-night meals caused people to gain weight by reducing the body's ability to burn fat.

The findings emerged from a study by the Perelman School of Medicine at the University of Pennsylvania, which further confirms that eating late at night has a host of negative health effects.

"We know from our sleep loss studies that when you're sleep deprived, it negatively affects weight and metabolism in part due to late-night eating, but now these early findings, which control for sleep, give a more comprehensive picture of the benefits of eating earlier in the day," said lead author and research associate professor of psychology Namni Goel.

How they conducted the research

The researchers set out to study the metabolic consequences of consistent delayed eating compared to daytime eating.

They instructed nine adults of healthy weights to spend eight weeks eating only during the daytime, which involved consuming three meals and two snacks between 8am and 7pm.

Then the group followed a delayed eating routine - having three meals and two snacks from noon to 11pm - for eight weeks.

There was a two-week break in between to make sure there was no carry-over effect.

Their sleep patterns were kept consistent - between 11pm and 9am - in both phases to eliminate any effect from lack of sleep, which is linked to obesity.

At key points across the study, the researchers measured changes in weight, metabolism and energy used. They also made sure that all measures returned to baseline in the two week break, before the next phase was begun.

Key findings

The research discovered that when participants ate later, compared to when they ate during the daytime, their weight increased.

They found late-night meals caused people to gain weight by reducing their body's fat metabolism - the process by which fats are broken down and used for energy.

Tests revealed that eating later led the participants to metabolise fewer lipids or fats.

It was also found that delayed eating led them to store carbohydrates - which can lead to weight gain and raised blood sugar and insulin levels.

And indeed insulin and fasting glucose were found to be higher when people ate later, and their cholesterol and triglyceride levels rose too.

Eating earlier in the day was found to produce hormone changes that help you feel full longer and therefore not overeat.

For daytime eaters, the hormone ghrelin, which stimulates appetite, peaked earlier in the daytime.

Meanwhile, leptin, which keeps you satiated, peaked later, suggesting that the participants received cues to eat earlier, and eating earlier most likely helped them to feel full longer.

This suggests that eating earlier may help prevent overeating in the evening and at night, say the researchers.

What the experts say

Previous studies have suggested similar results, but this is the first long-term study - albeit a small one - that has analysed the health effects of the timing of eating patterns that also controlled for sleep-wake cycles, exercise and macronutrient intake.

Professor Kelly Allison, senior author on the study, said: "While lifestyle change is never easy, these findings suggest that eating earlier in the day may be worth the effort to help prevent these detrimental chronic health effects."

"We have an extensive knowledge of how overeating affects health and body weight, but now we have a better understanding of how our body processes foods at different times of day over a long period of time."