Intermittent Fasting vs. Time-Restricted feeding
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The new talk of the town in the scientific community pertaining to longevity, weight-loss, and all things nutrition (or lack thereof with fasting) is two eating strategies with names that made me chuckle slightly a bit inside. Basically, one is, "don't eat" and the other is, "don't eat so late". The concepts didn't make me laugh as much as their sophisticated names did, since both do have positive physiological results for weight-loss by increasing the Basal Metabolic Rate (BMR) or also known as (REE) Resting Energy Expenditure (Am J Clin Nutr. 2000 Jun;71(6):1511-5).
However, any prolonged incidence of not eating will of course, make you lose weight.
Terms
With Intermittent fasting (IF), it can be from a 24-48 hour period without sustenance. An alternating "eat today, not tomorrow, and repeat" situation is another variation A once a day meal and a "eat 5 days and don't for 2 days weekly ratio are two options as well. There are other types of fasting in the fasting realm with modifications on mostly how many day(s) out of the week will you not eat.
Time-restricted eating or feeding (TRE/TRF) on the other hand, gives you a timeframe to eat within the day. This timeframe allows for a person to have hours ranging from usually 8-12 hours to eat from the time they've waken up. So let's say; if I wake at 7AM and I will stop eating at 7PM, since I'm following the higher end of the Time-restricted range of 12 hours. (Cell MetabolismVolume 20, Issue 6, p991–1005, 2 December 2014). Even if I stay up til 11PM and am a bit hungry, I would no longer eat for the night.
Yes, Time-restricted feeding can be seen as a type of intermittent fasting under it's big umbrella. However, my point is with Time-restricted feeding, the difference is that you're still eating meals throughout the day, it's just cut short or you start eating later in the day, still keeping it between a set amount of hours. With fasting, it's either you don't eat the whole day(s) or just have one meal a day. You pick the approach.
Any Studies? Anyone?
To date, there hasn't been much long-term studies with the effects of fasting on humans. We do have a lot of studies performed on rats and researchers concluded it has been positive. News flash, we're not rats. Also, there has been many studies that have only been performed for a very short period of time.
One study, has an 8-week duration period,(Free Radical Bio Med 2007;42:665–74), which doesn't provide as much insight as a study that has been prolonged since it would be great to have an eating pattern that isn't just going to last 2 months. Another issue within the study is that there was a second variable in the experiment of still having calories, but reduced to a certain percentage, becoming a cofounding condition that provided erroneous results.
If you're trying to find out the results to a conclusion from one variable (fasting), shouldn't you NOT include another varying factor (calories) different from the independent variable? Just trying to make sense of the basics of the scientific method and not deviate from the process.
It doesn't make it a reliable source of information because instead of measuring one variable, now you have two measurements with one result and the accuracy of which one was the major identifiable factor cannot be determined.
So Which is Most Effective?
It's not a coin toss at all to see which method is better. Time-Restricted Feeding is hands down the better option compared to any of the variations of fasting. It's like TRF/TRE became it's own entity and deflected away from the intermittent fasting banner because even though it can be considered under the same category, it's concept is much different in that there's a time you stop eating all of your meals compared to not having any at all for the day.
I generally like to receive my information and facts through scientific journals, books, and scholarly literature; however Dr. Rhonda Patrick provided a great explanation about TRF. In a very recent Podcast with Joe Rogan (Joe Rogan Experience), Dr. Patrick provided major health benefits of the plan and has been, in my opinion, very well-grounded information.
Concerns
A study from Am J Physiol. 1990 Jan;258(1 Pt 2):R87-93, found that a 48-hour fast provided an increase in epinephrine response, thus increasing thermogenics and an increase in some calories burned.
It's been years (almost a decade) since taking Anatomy and Physiology, however I remember there's a system that we all have called the "Fight or Flight" or activating the sympathetic nervous system. When this system is activated, it will flood our system with not only the epinephrine, but cortisol as well.
Artificially screwing around with your fight or flight system in my own hypothesis, makes fasting a terrible way to try to lose weight since it can down the road, make you hold onto those extra calories a whole lot easier since you're limiting nutrients severely. Our bodies are a lot smarter than we think.