To Lose Weight Don't Eat Late

Late eating and weight loss

Late night raids on the refrigerator or going to a 24-hour diner after a night out may be putting a big damper on any weight loss efforts. If you want to lose weight, researchers are suggesting that eating at irregular times, such as late at night, may contribute to weight gain.

The Northwestern University study is the first ever to provide causal evidence that weight gain involves more than the number of calories we eat: when we eat has an impact on weight loss and weight gain. This may mean that people who want to lose weight need to change the timing of their meals along with what they eat and how much they exercise.


Obesity is being called an epidemic by many experts, and it is a global problem. More than 300 million adults around the world are obese. According to the Centers for Disease Control and Prevention, 34 percent of adults in the United States are obese, and the percentage of children age 6 to 19 who are overweight ranges from 17.4 to 18.8 percent. These figures remain high and have been growing despite the popularity of weight loss diets and weight loss programs in the United States.

The current study dispels the results of a study about weight loss and weight gain published in December 2005 in Obesity Research. In this study, scientists at the Oregon National Primate Research Center at Oregon Health & Science University stated that their research with rhesus monkeys showed that eating at night was no more likely to cause weight gain than eating during the day.

In the Northwestern University study, the scientists found that mice who were fed a high-fat diet during normal sleeping hours gained significantly more weight (48% increase over baseline) than mice who ate the same diet during normal waking hours. The researchers came to the conclusion that modifying when we eat and better timing of meals can greatly impact weight loss efforts. Further studies will investigate the molecular basis behind why when we eat has an effect on weight loss and weight gain.

Arble DM et al. Obesity 2009; published online September 3, 2009
Sullivan EL et al. Obesity Research 2005 Dec; 13 (12): 2072-80