Late night eating and weight gain

BY Added Health Editorial Team | 13 December 2022

How often have many of us reached for a snack during the evening?

We’ve already eaten dinner but a few hours later we find ourselves sitting in front of the TV or laptop craving a bite to eat — a packet of crisps, a couple of biscuits, the open bar of chocolate in the cupboard… any one of them seem like a great idea at the time.

Does it really make a difference?

Unfortunately, eating late in the evening is linked to higher body weight and an increased risk of obesity. The reasons for this were unclear but a recent study in the US studied the effects of different meal schedules on a group of participants over six days. They found that those who ate later (by eating their last meal of the day just two and a half hours before bed) displayed each of the following:

  • They were hungrier the following day.
  • They had an altered ratio of hunger hormones in the blood which pushed the body towards a “hungrier” physiological state.
  • They burned fewer calories the next day.
  • The expression of certain genes shifted their bodies towards a fat-storing mode.

How can a late-night snack do all that?

The precise reasons for these changes are unclear although they may well be connected to our natural human circadian rhythm. Eating in the later hours when it’s typically dark outside might disrupt the body’s typical circadian pattern thus altering the way we burn calories and store fat in our bodies.

The take-home message

Overall, the changes caused by late eating predispose us to gain weight so it’s worth trying to avoid eating a meal too late in the day and definitely avoid snacking in the hours leading up to bedtime.


Vujović, N., Piron, M.J., Qian, J., Chellappa, S.L., Nedeltcheva, A., Barr, D., Heng, S.W., Kerlin, K., Srivastav, S., Wang, W. and Shoji, B., 2022. Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity. Cell Metabolism34(10), pp.1486-1498.

Feng, X., Wang, M., Zhao, Y., Han, P. and Dai, Y., 2014. Melatonin from different fruit sources, functional roles, and analytical methods. Trends in Food Science & Technology37(1), pp.21-31.