When should we eat to avoid getting fat? Is it true that late night meals make you fat or is it all just a matter of calories? What is the reality?
One of the recurring tips of diet and nutrition gurus is not to eat late at night. Time to dispel another myth!
DISTRIBUTION OF CALORIES IN THE DAY
Let's start by explaining the issue simply and clearly. First of all, let's say that our metabolic rate drops at some point in the day and it takes hours to recover.
Yes, sir. Let's do a few more Affairs:
- Our metabolism drops by 10% this period
- This period starts from 19:00 and
- We need 2000Kcal to keep our weight down
Good so far?
In short, since half of 2000 is 1000, but we have to take into account the 10% deceleration of these 1000Kcal, in the worst case we should have this calorie distribution:
Isn't it nice to see what the theory means in practice? Because that now raises some other questions.
Like, for example, if I don't eat much during the day, will I get fat if I eat before bedtime? Because that's what I read online.
Simple answer. Not if our total calorie consumption in a day does not exceed our total daily energy expenditure in calories, which in this example is 2000Kcal. And here is the simple reason. In this example let's assume that we eat 500Kcal during the times of the day when the nutritional gurus tell us there will be no side effects:
If you eat lightly, or even not at all during the day, it means you are in an energy deficit, which you will simply make up for later. In our example this deficit is 600Kcal, since 1100Kcal (the calories we should have taken in during the day) minus 500Kcal equals 600Kcal.
Which means that in this particular case, if we eat 1500Kcal before bedtime, we will have:
Just as much as we should have eaten anyway.
In short, at least in the short and medium term, it makes absolutely no difference what time you eat. If you eat a little you will be in an energy deficit, and if you eat a lot you will be in an energy surplus. Whether foods are metabolized more slowly during one period of time should not be of concern, as this is compensated for by the fact that they are metabolized more quickly during another.
So it is the sum of the calories we take in during a 24-hour period that matters, not when.
FROM THEORY TO PRACTICE
So that's it? That simple?
Oh, no. Did you think I'd leave you so soon? Things are a little more complicated in reality. You notice how I used the words "short-term" and "medium-term". But what about the long-term level?
Let's start by landing on reality by assuming that indeed the Resting Energy Expenditure does drop during 24 hours, but not as you are being described.
As you can see, the Resting Energy Expenditure is at its peak in the afternoon, and even at 21:00 it has not fallen below the levels of the morning. So the metabolism is doing its job just fine until relatively late. So, in theory, reality contradicts what the gurus say, since by 21:00-22:00 we could say that we are in the "safe zone".
Reality: After a meal, two things that happen are that triglyceride and insulin levels in our blood rise. We've talked about insulin levels up and down in "How our body works II" and in "How our body works III". For postprandial lipemia, the peak is reached about the third or fourth hour after fatty acid intake, and the cycle is usually completed after six to eight hours.
It has been proven over and over again that exercise after a meal has a positive effect on both triglyceride levels, but also the insulin and glucose levels. So, with that in mind, we have an indication that in the long term, a sedentary lifestyle following a meal can have serious health consequences.
In fact, research shows that late-night meals are indeed associated with negative outcomes not only in lipids and the sugarbut metabolic syndrome in general.
HORMONAL INTERACTIONS
From this we can conclude that it is probably a good idea not to eat right before bedtime. But when can we say that it is the optimal time for the last meal of the day?
For starters, let's look at growth hormone or HGH or otherwise GH. This has several roles, but the ones we are interested in in this case are the following:
- Together with IGF-1 it signals the Development to children and adolescents
- Indicates lipolysis and proteolysis
- Although GH levels fall after adulthood, lower than normal GH levels for age are associated with cognitive dysfunctions, cardiovascular problems and metabolic syndrome
Although it is not the case here, I should also note that, in the opposite of the previous case, i.e. higher levels of growth hormone are associated with shortness of life, while the low with the longevity, but that probably has more to do with heredity in combination with calorie restriction.
The problem with growth hormone is that, although it decreases continuously after adulthood, its levels fluctuate throughout the day.
So, if we are interested in growth hormone, we need to make sure that it can do its job. And as we can see, even in development, growth hormone is secreted primarily during sleep.
Which means that, since GH not only plays a role in lipolysis, but is also insulin compensatory hormone, it is advisable that our dinner is not too big and that we eat it 3-4 hours before bedtime.
Which makes sense, since melatonin stimulates its secretion.
Melatonin is at the heart of the circadian rhythm, as it synchronizes the internal hormonal environment with the light/dark cycle of the external environment.
Now, melatonin levels depend on the time of the year, the time of day and like most hormones, falls over the years.

As you can see, melatonin levels start to rise from 18:00 (as always, there are variations from person to person and essentially the range is 18:00-23:00).
So melatonin, in turn, affects glucose metabolism and in a dramatic way, since the pancreatic cells responsible for insulin secretion have melatonin receptors.

This means that when we eat while our melatonin levels are high, our sugar levels stay high for longer, affecting our growth hormone, and in the worst case scenario, our sugar levels stay high for longer, this phenomenon contributes to type II diabetes, as about 30% of the world's population has a mutation in these receptors, which makes it much more vulnerable.
And since we've come this far, it's good to note that low melatonin levels also linked to metabolic syndrome.
Since we are talking about circadian rhythms, we could look at more hormones, such as cortisol and insulin, but I think that would not add anything meaningful.
So we have and we say:
- Although late-night meals are not fattening, it is advisable to keep them to an absolute minimum, as they can have negative long-term consequences
- Meals should take place from 07:00 to 19:00 or at worst 20:00 and at least 3 to 4 hours before bedtime
- Do not lie/lie down for long periods after a meal
- Sleep should be good both quantitatively and qualitatively
-Suprastratum: The authority on health, fitness and nutrition