When I was medical school, I noticed one of my friends had lost a bit of weight (intentionally). Even though I was not really interested in things like weight control and diet in those days, my curiosity got the better of me and I asked him how he did it. Had he cut back on fat or upped his exercise, I wondered. His response was that he was doing no more exercise than before and he was eating precisely the same food as before. The only change, he told me, that he was refraining from eating and drinking anything but water after 6.00 pm until the following morning.
This conversation came back to me this week on reading the summary of study in which young men spent two weeks on each of two eating regimes [1]:
1. normal eating
2. normal eating except no food between 7.00 pm and the following 6.00 am
Food intake and weight was calculated in both settings.
Here are the main findings of the study:
- In setting 1, individuals ate an average of 700 calories each day between 7.00 pm and 6.00 am.
- In setting 2, individuals ate no calories during this time period (as instructed).
- Over the course of the whole day, individuals in setting 1 ate an average of about 2660 calories each day.
- In setting 2, average daily intake was about 2420 (about 240 calories less than in setting 1).
- In setting 1, average weight change was a gain of 0.6 kg, while in setting 2, there was an average loss of 0.4 kg.
This is a small study, in a quite confined subset of people (young, healthy men) and relatively short in duration. However, it does provide evidence which suggests that cutting out evening eating may not be fully compensated for by additional eating at other times of the day, and may promote weight loss.
Another way of looking at this dietary tactic is as a form of intermittent fasting which I’ve written about here.
References:
1. Le Cheminant JD, et al. Restricting night-time eating reduces daily energy intake in healthy young men: a short-term cross-over study British
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I wonder if this works for *any* meal ie “skipping $mealname$ reduces total calorie intake as compensation is less than calories omitted”.
My understanding is that it has something to do with your 24 hr hormonal clock, simply put, we’re not set up to deal with and digest food optimally in the evening hours, our bodies are busy doing other stuff. Other factors could possibly play a part, including some calorie restriction and the mere fact that people know they are being monitored for weight loss.
Makes total sense – I always wake up slimmer if I’ve eaten dinner early
This study would have been even more interesting if they had picked another long fasting window that doesn’t cover the evening hours, and compared the results with the evening fasters. Almost any diet compared to SAD results in improvement, so it doesn’t tell us all that much.
The benefits surely have something to do
1) with the normal pathways of storing any surfeit of glucose, and
2) giving insulin and other hormones a chance to normalise.
If we eat a meal and the meal contains calories in the form of carbohydrates (as many a meal does) then a rush of (postprandial) glucose enters the blood. Since the balance of blood sugar must be kept a narrow Goldilocks zone surplus glucose gets spirited away by conversion to glycogen. Glycogen is a kind of polymer variation upon glucose and it can be stored in the liver and muscles mass without ill-effect and in a way glucose cannot. At some point after a meal we begin drawing back down from glycogen reserves and converting them back to glucose.
I’ve always marvelled that the capacity to store glycogen is broadly in line with our energy requirements needed to get us through the night, when we’d normally be at rest.
To get hormones, especially insulin, under control and normalised I’d suspect it would be natural and adaptive if glycogen stores are depleted before we rise so that the body spends a short time exploiting fat burning mode (lipolysis and ketosis) which probably wouldn’t happen so readily if insulin levels remain high and glycogen stores were not depleted.
If a person is locked into hyperinsulinaemia, even in a mild way, it isn’t easy to break out of a viscous if eating late and only shortly before retirement is the usual habit.
In other words it probably isn’t an adaptive arrangement if a persons glycogen stores are always full and never get totally depleted. Re-stabilising insulin seems to aid the ability to self-regulate appetite and discourage over-eating.
The very old saying. “Eat breakfast like a king, lunch like a prince, and dinner like a pauper“. Sounds pretty good to me.
“it isn’t easy to break out of a viscous” CIRCLE “if eating late and only shortly before retirement … “
The study had no food after 7pm, and the traditional school of thought is ‘no food after 6pm’ – I’m wondering if you can apply this to shift workers, night workers etc? Can one move the dinner time later as long as ‘breakfast’ doesn’t come any sooner than 11 hours later? (ie: dinner at 10pm, breakfast at 10am)
“Eat breakfast like a king, lunch like a prince, and dinner like a pauper“
Yep, Eddie some of these old expressions and sayings, ‘heuristics’, are darned reliable.
Those viscous circles are really sticky… 🙂
Leptin takes 4 hours to reach the brain. So the rule is to eat nothing within 4 hours before bed, or your brain is unable to asses the fat status. So how can the brain know when to send in the uncoupling proteins?
Next, the hormone sequence that leads to the release of growth hormone during deep sleep is kicked off with a surge in prolactin in the evening. Raised insuline levels interfere with this proclactin release and thus the release of growth hormone.
(If my spelling is not correct; my native language is dutch).
@Chris
Pedant here… interesting observations, but perhaps you meant a vicious circle? A viscous circle sounds REALLY tricky to escape (treacle, tar, crude oil, etc).
@ Helen
A good point very well made; quite right and thanks .. .. and I wish I could spot my typos with the ease I can make ’em.
From now on I am going to take care to type vicious and reserve viscous for the trickiest of situations and the stickiest of circumstances. 🙂
Hello. I think you can supercharge any diet but restricting when you eat in a time restricted period. Jonh – Would you like to feature on my website http://www.5thingstodotoday.com?
Many people find that eating within 8 hours (or 6) window is very benefitial . For such reason people not only avoid eating late, but also delay their breakfast and avoid eating snacks.
Or as the Mongolians say, ” Eat breakfast yourself, share lunch with your friends and give dinner to your enemies”
I find this really interesting. I am actually looking to lose a bit of weight myself at the moment and I think I will give this a try.
I’m not sure if I’ll manage to avoid food from 6pm to 6am but I should manage 8pm – 8am. I’m not sure how successful this will be – I am hoping it will be dependent on the time I go to bed. Normally this is around midnight which is 4 hours after my food deadline. Another poster said that the 4 hour rule is important so hopefully this will work out for me.
Thanks for the article!
I agree with you john. Earlier when I used to be obese, I was addicted to the junk and fast foods. When I realized how important it was controlling them, I have gained much weight that can make me obese. I’ve started avoiding those junk and fast foods which can act as a barrier for losing weight. I have started taking a healthy diet filled with fresh fruits and veggies and started doing workouts. Now, I am back to my previous physic, which makes me happy these days.