Based on many nutrition questions that have been asked on these boards, I learned that the time we eat our meals has no direct impact on health or weight gain or loss. If anything, it’s the unhealthy and high-calorie meals that we tend to eat later in the evening that are the culprit.
But an excerpt in this article in the New Yorker says otherwise:
There could be indirect impacts that explain the results in the study. For instance, eating large high-calorie breakfasts could tend to increase metabolic rate during the day while people are active, thus burning more of the calories.
How could time ever not matter? If you eat four slices of pizza at midnight and then go to bed, you’re not burning any of that off by sleeping and you are gaining fat.
Or is that incorrect?
…to replace the fat you burned earlier in the day when you didn’t eat the pizza but still had activity. Assuming the simple “calories in vs. calories burned” model is accurate, the order and timing shouldn’t matter, just the total amounts over time. I’ve not seen the research study talked about above, but if timing does matter, that would definitely be an interesting discovery.
As opposed to eating them 4 hours before bed and, um, what? Sitting on the couch watching TV isn’t appreciably different than sleeping when it comes to burning calories. So I don’t think that’s a major factor.
If that’s true it seems like a big oversight in human metabolism. You’re a hunter gatherer on the edge of survival and you might live or die depending on the time of day you eat?
Let’s say you don’t regularly exercise, and ate a normal dinner at a normal time (say…six?), but then you drank ten beers and THEN ate all that pizza at midnight? What about then?
It would be the same as if you had the beer, pizza and normal dinner all when you woke up at 6am and then didn’t eat/drink anything for the rest of the day.
At least that’s how it’s supposed to work. The excerpt in the OP says otherwise, which is why it raised my eyebrows.
Just as a matter of general health (as opposed to weight gain/loss), I think most people don’t sleep as well on a full stomach.
My understanding: Eating breakfast wakes up your metabolism for the day. Skipping meals slows the metabolism. It’s not that eating right before bed is bad or will make you gain weight. It’s not eating first thing in the morning that hinders weight loss.
What is the difference in terms of calories burned/metabolic rate while engaged in normal, quasi-sedentary after dinner/before bed activities versus sleeping?
That’s pretty much the open question. Almost anything you read on the Internet about “metabolic rates” (or for that matter, nutrition in general) is bunk or wild speculation. The assumption has always been that the homeostasis rate (pretty much just keeping your body alive) dominated, and that calories were basically like a bank account: when you consumed or expended them didn’t matter much.
The study lends some evidence to the idea that maybe the calorie usage rate (or more accurately, the calorie usage efficiency) does change over the day. I don’t know how much you can read into one study, though.
The problem with how most people misuse the “calories in calories out” model is that they mistakenly presume that the “calorie out” side is not impacted by aspects of the “calories in” side.
The reality is that we not are dealing with a car here. This machine reacts in more complex ways.
Here’s a mouse study that documents the impact of timing of intake on weight gain.
Another study in mice, this one demonstrating that restricting the same calories in a high fat diet to be eaten in an 8 hour window of their naturally active times versus ad lib over 24 hours led to less obesity and less metabolic resistance. It is a pretty damn impressive study. Eating during times of day that organisms are entrained to not be active during disrupts a host of metabolic pathways tied to circadian rhythms.
Here’s a blog post that summarizes a few human studies.
Interesting stuff.