I usually eat at 9-9.30PM and go to bed at 10.30PM. Yet some people say they have dinner at 6PM? That's so weird...
Maybe it's because I'm from a sunny area and over here the sun stays up later (Mediterranean).
Are there drawbacks when it comes to digestion/assimilation?
I think that if you are fit, have good body comp and no adrenal fatigue, then you're probably fine to continue eating on your current schedule.
However, if you have body fat to lose or hormonal issues to clear up... Then I suggest eating earlier.
From Chapter 15 in the book "Mastering Leptin" by Byron J. Richards with Mary Guignon Richards, the authors say this:
Leptin levels rise at night. They follow a twenty-four hour pattern of natural rhythm of natural balance. They peak in the evening hours and are the highest during the first two hours of sleep. They gradually fall during the night and reach their lowest level around noon; then they begin to rise again. ... When leptin works properly, a high leptin level tells you that you are full; there is no desire to eat. Therefore, it is completely natural not to be hungry after dinner or before bed. There are a variety of reasons for this, one of which is that your body has functions other than digestion to carry out during sleep. ... A person with leptin resistance, too, has higher levels of leptin at night, but the brain is not able to perceive the message.
With this in mind the authors recommend...
Rule 1 - Never eat after dinner. Allow eleven to twelve hours between dinner and breakfast. Never go to bed on a full stomach. Finish eating dinner at least three hours before bed. ... Improperly timed eating can disrupt thyroid hormone, growth hormone, adrenal hormones, sex hormones, and melatonin, and it throws the body out of rhythm...
Sleep is a prime metabolic time. It is when individuals can access the stores of fat that they wish to lose. This works well when no food has been consumed for eleven to twelve hours and the quality of sleep is good. ... During the night, your body gradually begins to burn a higher portion of fat for fuel. Nine hours after dinner it is quite likely that the readily available fats have been used, and your body will dip into the fat savings account. Therefore, nine to twelve hours after dinner are prime fat-burning hours, in terms of accessing the fat stores in the buttocks, thighs and stomach. If anything is eaten before bed, this prime fat-burning time is shut off! This principle is not going to change; it is a fact of biochemistry.
This all depends on your own needs and your own schedule. Judge your fitness, health, and schedule accordingly and tweak your mealtimes as needed!
P.S. This rule worked for me.
Martin Berkhan wrote an awesome post on exactly this subject:
Long story short: timing doesn't seem to affect anything as long as excess calories aren't being consumed due to eating later.
I always eat 100g net carbs of sweet potato right before falling asleep, whether I ate dinner itself recently or not. I think of carbs as a glycogen repletion supplement rather than as food per se, so it's kind of unhinged from my meals. I feel great doing so and have no complaints. I've actually lost body fat since I've been doing this, so I really doubt it could make you fat.
I grew up in the 50s with a stay at home mom. We always had supper as we called it between 5 and 6 as soon as my dad got home. The children also went to bed at 8:00. That supper time continued in college because the chow hall served between 5 and 6. I taught overseas for a semester each in Italy and Greece and nearly starved to death waiting to eat at bedtime! Nothing weird...just different cultures.
I seem to recall reading in somewhere that insulin (possibly through it's relationship to IGF-1) suppresses growth hormone release which may be one reason to avoid eating late at night, especially if it is a carbohydrate rich meal.
I've eaten later in the evening off and on for years and my body weight/composition didn't change from when I was eating at 5pm. These days, I eat around 8pm. Getting home from work at 5 and working out at 6 for roughly an hour during the week, then a shower, then cooking. I can't eat any earlier really. I think what you're eating matters more than what time it is, and only eating if you're hungry. I think night time munchers who graze into the evenings after already having dinner are the ones putting on weight from 'late night eating'.
I don't think its that weird. I am usually pretty hungry when I get home from work so I make my dinner. 6 is maybe at the very earliest of the dinner time window for me though, 6.30-7.00 is usually good for me.
Since I've been doing paleo I've fallen into the habit of eating a pretty early dinner. It's summer here and it doesn't get dark until late so I don't think that affects it. I just eat when I get hungry and it's usually early and then I don't feel hungry anymore until I go to bed. I do tend to wake up pretty early though (around 5:30 to 6:00 AM) so I think that puts everything on an earlier schedule. I go to bed at 9:00 PM, even though it's still light outside.
The traditional Ayurvedic wisdom says to not eat after the sun has gone down. This feels right to me intuitively, and it allows you to eat later in the summer than the winter.
Also, I don't know enough about the endocrine system to exactly say, but I do know that the spectrum of light changes radiating from the sun at sunset (gets more red/orange) and that gives our bodies a signal to make melatonin, etc. That seems to curb my hunger, and I'm sure it sets off a cascade of signaling in the body that may be better without adding food into the picture.
This is my speculation but it seems pretty reasonable.