Is eating late bad for your health?

If you’re someone who tends to eat dinner quite late at night, or perhaps you like a snack before bed, you might be asking yourself whether this is impacting your health. Maybe you’ve heard that you won’t be burning it off so it will get stored as fat, or you’re considering intermittent fasting but not sure whether it’s worth it. Let’s discuss!

How might meal timing impact health?

• Sleep disruption: Eating late may mean that you can’t lay down comfortably to sleep and may experience indigestion, which could disrupt your sleep. It may cause you to wake up more throughout the night (Iao et al, 2022; Chung et al, 2020)

• Eating later might affect your weight: An intervention study of healthy adults in the United States reported that calorie consumption after 8pm was associated with higher BMI, even after taking into consideration age, sleep duration, and sleep timing (Baron et al, 2019). Eating larger meals earlier in the day, rather than later, appears to be associated with lower BMI (Xiao et al, 2019). This may be because hunger hormones are affected by the time you eat - those who eat earlier in the day tend to feel less hungry than those who eat later, so those who eat later may eat more to satisfy that hunger (Vujović et al, 2022). You may also burn slightly fewer calories digesting the meal if you eat later rather than earlier (Kindsey et al, 2015).

• Impact on blood sugar and diabetes risk: A recent study of more than 850 people in the UK found that those who regularly snacked after 9pm had higher levels of HbA1c, a marker for diabetes risk, and greater spikes in blood sugars and fats after daytime meals than those who did not typically consume late-night snacks (Bermingham et al, 2024).

However...

This all seems like eating late is a bad idea, but a lot of the studies are observational and don’t control for other factors like the food or amount consumed. It may be that in general, people who eat late also tend to eat MORE, or more high calorie, high fat/sugar foods like takeaways or biscuits. This is likely to be the biggest factor which leads to the association between eating late and higher BMI and risk of metabolic diseases. If you were to eat exactly the same thing on two days but one day you ate it 3 hours later than the other, the difference on your health would be minimal. Therefore, if you are conscious of what and how much you are consuming, and choose nutritious, balanced meals, I wouldn’t be too concerned about eating a little later.

The bottom line:

If you are able to eat earlier rather than later, there may be some benefits to this, including better hunger regulation.

If you are a late night-snacker, having a point in the evening where you stop eating may help you to regulate your overall intake.

If you cannot avoid eating late, don’t worry - make sure you are well-fuelled throughout the day to make portion control in the evening easier, and try to fill up on healthy nutritious foods as much as possible.

References:

• Baron, K. G., Reid, K. J., Kern, A. S., & Zee, P. C. (2011). Role of sleep timing in caloric intake and BMI. Obesity, 19(7), 1374-1381.

• Bermingham, K. M., May, A., Asnicar, F., Capdevila, J., Leeming, E. R., Franks, P. W., ... & Berry, S. E. (2024). Snack quality and snack timing are associated with cardiometabolic blood markers: the ZOE PREDICT study. European Journal of Nutrition, 63(1), 121-133.

• Chung, N., Bin, Y. S., Cistulli, P. A., & Chow, C. M. (2020). Does the Proximity of Meals to Bedtime Influence the Sleep of Young Adults? A Cross-Sectional Survey of University Students. International journal of environmental research and public health, 17(8), 2677. https://doi.org/10.3390/ijerph17082677

• Iao, S. I., Jansen, E., Shedden, K., O’Brien, L. M., Chervin, R. D., Knutson, K. L., & Dunietz, G. L. (2022). Associations between bedtime eating or drinking, sleep duration and wake after sleep onset: findings from the American time use survey. British Journal of Nutrition, 127(12), 1888-1897.

• Kinsey, A. W., & Ormsbee, M. J. (2015). The health impact of nighttime eating: old and new perspectives. Nutrients, 7(4), 2648–2662. https://doi.org/10.3390/nu7042648

• Vujović, N., Piron, M. J., Qian, J., et al. (2022). Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity. Cell metabolism, 34(10), 1486-1498.

• Xiao, Q., Garaulet, M., & Scheer, F. A. (2019). Meal timing and obesity: interactions with macronutrient intake and chronotype. International journal of obesity, 43(9), 1701-1711.