Does Eating At Night Make You Fat?

Many gym-goers believe that eating at night increases fat storage.

This is simply not true.

I don’t want any of you to fear the time of day when it comes to fulfilling your daily calorie intake – especially those of you who happen to work night shifts!

So let’s break down this old fitness myth and debunk it once and for all.

Why Do People Believe This?

The majority of fitness magazines promoted this advice during the 1980s and 1990s.

And the theory behind it is pretty solid, too.

When we consider that our metabolism slows down during periods of prolonged inactivity (e.g. when we sleep, or when we binge watch Netflix for 5-hours), it makes sense that any food which is consumed during these periods of inactivity will not be needed for energy, and will be stored as fat instead.

So this is why people who are trying to lose weight (and also bodybuilders) have long been told to eat their meals during the day when they are more active, and avoid eating after 6pm.

It kinda makes sense, doesn’t it?

But it also leaves us with a few unanswered questions:

• Are there any studies showing people eating the same amount of calories (but at day and night) which actually show more fat being stored?
• If a nurse works a 12-hour shift is he/she supposed to avoid eating dinner just because the clock says 10pm?
• Do these rules apply to everybody or just those trying to reach a very low body fat percentage?

Don’t worry, all will become very clear in the next section…

What Does Science Say?

It turns out the metabolism doesn’t work as first theorized.

A 1999 study showed that the rate at which we burn calories (your BMR) doesn’t really change much throughout the entire day, which means your body will process calories in much the same way, regardless of when you eat. (1)

This research sent shockwaves through the bodybuilding community when it was first published in the European Journal of Clinical Nutrition, with many long-time gym rats (myself included) insisting that “It’s gotta be wrong!”, and waiting for more research to be done before accepting it.

It didn’t take long for that research to arrive, with studies in 2002 and 2003 re-confirming the facts. (2, 3)

There’s also a few studies out there which deliberately had participants eating the bulk of their calories at night.

Did they grow an extra layer of belly fat? No.

The best of these studies was a monstrous 2011 trial published in Obesity, in which one group of participants spread their calorie intake evenly throughout the day while another group ate their calories in the evening. After a six month process, both groups lost roughly the same amount of body fat (daytime = -21lbs, evening = -25lbs) and interestingly the evening group reported feeling less hungry. (4)

This shows us that there is no connection between late night eating and weight gain, and these findings have since gone on to be re-confirmed in further trials. (6, 7, 8, 9, 10)

But despite all of this evidence, this particular myth always finds a way back into the headlines – and this is largely down to poor reporting by the media.

It happened just last year, when several news outlets claimed to have seen solid proof that eating late at night causes fat storage. Upon further inspection we can see that the study they cited has two devastating flaws; a) there were no calorie restrictions in place, and b) it only lasted seven days. You could skew those results with one big poo! (11)

So it really is a case of the best diet is the one you can stick to, and with that in mind, I advise you to eat your meals however best fits your lifestyle. (5)

Further Reading:

If you enjoyed this blog, then you’ll probably also like reading these.

>> The Rules To Ripped
>> Common Reasons For Always Feeling “Zonked”
>> Clean Eating Sucks And You Fucking Know It

References:

1. Seale J. L., et al. Relationship between overnight energy expenditure and BMR measured in a room-sized calorimeter. Eur J Clin Nutr (1999).
2. Zhang K, et al. Sleeping metabolic rate in relation to body mass index and body composition. Int J Obes Relat Metab Disord (2002).
3. Mischler I, et al. Prolonged daytime exercise repeated over 4 days increases sleeping heart rate and metabolic rate. Can J Appl Physiol (2003).
4. Sofer S, et al. Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity (2011).
5. Howell S., et al. “Calories in, calories out” and macronutrient intake: the hope, hype, and science of calories. Am J Physiol Endocrinol Metab (2017).
6. Stratton M. T., et al. Four Weeks of Time-Restricted Feeding Combined with Resistance Training Does Not Differentially Influence Measures of Body Composition, Muscle Performance, Resting Energy Expenditure, and Blood Biomarkers. Nutrients (2020).
7. Tinsley G. M., et al. Time-restricted feeding plus resistance training in active females: a randomized trial. Am J Clin Nutr (2019).
8. Seimon R. V., et al. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Mol Cell Endocrinol (2015).
9. Sensi S., et al. Chronobiological aspects of weight loss in obesity: effects of different meal timing regimens. Chronobiol Int (1987).
10. Nonino-Borges C. B., et al. Influence of meal time on salivary circadian cortisol rhythms and weight loss in obese women. Nutrition (2007).
11. Zaman A., et al. Eating later in the day may be associated with obesity. The Endocrine Society (2019).