The pitfalls of late-night eating

Eating late at night can cause weight gain and impair fat metabolism, according to the first experimental evidence of prolonged delayed eating versus daytime eating.

It can also raise insulin, fasting glucose, cholesterol and triglyceride levels, say the authors from the University of Pennsylvania.

Their findings reflect those found in similar but shorter-term studies.

In this case, nine healthy weight adults underwent two conditions, one of daytime eating (ie, three meals and two snacks consumed between 8am and 7pm) for eight weeks and another of delayed eating (ie, three meals and two snacks eating from noon to 11pm) for eight weeks.

There was a two-week washout period between conditions to make sure there was no carry-over effect. The sleep period was held constant, between 11pm and 9am.

The researchers found that when participants ate later, weight increased. Respiratory quotient also rose during delayed eating, indicating that it led to metabolising fewer lipids and more carbohydrates.

They also found that a series of other measures reflecting negative metabolic profiles increased in the delayed condition, including insulin, fasting glucose, cholesterol and triglyceride levels.

A 24-hour hormonal profile shows how earlier eating helped to regulate appetite.