Study: Time-Restricted Eating Improves Cardiovascular Health for Firefighters
131 comments·October 5, 2022
I know this feeling well. This is a false sense of sharpness caused by undereating. You dont feel hungry or tired, just energized, light and strong.
I say false sense of sharpness, because you're actually not that alert. Yes, you can push yourself more, but your brain is in flight/fright mode and not thinking rationally.
> but your brain is in flight/fright mode and not thinking rationally.
Good cautious advice. Thank you.
Are you sure that that is all there is?
May I point to one paper of many that show proinflammatory cytokines to be reduced due to intermittent fasting?
“Under controlled conditions, [diurnal intermittent fasting] led to significantly decreased plasma levels of cytokines (IL-1β, IL-6, and IL-8), particularly IL-1β and IL-6 across 24 h.” – The effects of diurnal intermittent fasting on proinflammatory cytokine levels while controlling for sleep/wake pattern, meal composition and energy expenditure, 2019: https://journals.plos.org/plosone/article?id=10.1371/journal...
There are a bunch more. “intermittent fasting il-6” is a decent search to start with: https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=int...
We tend to eat up mechanistic reports that make us feel good about our preferred lifestyle, but in this topic you’d want to find experiments that increase alertness during IF (something that actually confirms an endpoint). Maybe they exist.
A classic example is the “antinutrients in plants” mechanistic fad while plants in a diet actually increase all health outcomes when put to the test.
Exercise causes a huge inflammatory response too. Thankfully we know better than to stop the analysis there.
It seems likely to me that your type 1 brain is more active and sharp, while your type 2 brain is overshadowed.
Irrational thinking seems unlikely. When glucose deficit, the brain functions fine on ketones. It might be you're experiencing your brain running on ketones.
I always significant increase in weight lifting exercises immediately upon starting fasting. Feels like an adrenaline response tbh.
It's a beautiful thing that we can rebrand "hangry" as "warrior mode". I also noticed this and just came to the conclusion that having breakfast and being in a good mood ("off edge"/"relaxed"/"opposite of warrior mode") was more worth it.
Huh, I've been intermittent fasting (eating only between 11am - 7pm for me) for most of this year, and haven't noticed any emotional changes like that.
But the physical ones definitely! I feel way healthier and my bloodwork just came back much improved as well.
For me, though, I don't think it has anything at all to do with the time restriction so much as the inadvertent calorie restriction. I've lost 30 lbs since I started, mostly because intermittent fasting has caused me to cut out my late night snacking and my greasy breakfasts.
In my experience, this is a good description of what happens. Eat less; lose weight; feel better.
Now let's find a way to put this in a pill so manufacturer reps will provide literature to doctors to prescribe it and insurance companies will pay the drug makers so everyone can go to pill maker conferences in Hawaii for education.
Been doing IF on-and-off for maybe 5 or 6 years. I get the same way.
Since you already called this "warrior mode", I'd recommend reading the warrior literature for tools and techniques to help deal with this in a positive way. If you're new to it, The Way of the Peaceful Warrior by Dan Millman is a great introduction and there should be enough references on it to start digging deeper.
There is a movie for the book as well but I don't recommend it.
This looks like a perfect antidote to my not-peaceful warrior experiences . Thank you.
Feeding is such an important and complex function, I believe there's also a strong psychological component in fasting. In my case, I'm losing about a pound per week doing light exercise and 15 hours of fasting daily.
Sometimes I've gone to sleep a bit hungry, and I've had dramatic dreams of being weak and emaciated. When I woke up I felt anxious, but just needed to go to the mirror, talk to my subconscious as if it was a child, and show him that we still have a long road to go, but in a few hours there will be a generous breakfast. We're not dying of hunger anytime soon. The anxiety simply vanishes.
These days there's no feeding anxiety anymore, but the subconscious is a very interesting companion. Another night I dreamed that somehow I was at my intended goal, and I didn't know how that happened so fast, and then felt an overwhelming happiness because now I could eat at any hour again! I woke up, and said "Nice try, subconscious", and happily resumed my sleep.
The brain in survival mode acts in funny ways.
> The doc basically said my latest bloods are outstanding
What was the change in blood reports?
I am surprised somone can simply reverse their 'serious' metabolic disease state in mere 6 months.
Then what would be the point of living a healthy lifestyle everyday if you can simply 'get healthy' in a matter of months when you need it.
I've wondered about this for a while. My friends don't give a shit about health and barely do any physical activity. They can get to 'outstanding' equivalent level in 6 months at the time of their choosing? That doesn't seem fair,lol.
Your body really doesn't want to be in some states (because you'll die) so certain markers/metabolic disease states like NAFLD and pre-T2D MetS will lower dramatically soon after the insult (chronic overfeeding) is stopped. RCTs have shown dramatic improvements in as little as a week or two. In my case, both my elevated AST and TG numbers halved a month into making significant lifestyle changes and almost all my bloodwork continued to improve dramatically into my next labs at 9mo and 1y.
That isn't to say there isn't accrued/long term damage, I think most people going through this sort of change will tell you that they are still dealing w/ health issues long term. I've notice that years after my initial interventions, my body still seems much more predisposed to weight gain for example - but trust me though, not feeling like crap is it's own reward. You can basically get used to anything and you don't really realize just how bad you were feeling (slowly getting worse over the course of a decade or so for me) until you turn it around.
Hey I'm really worried about sending out the wrong signal here, so let me tell you it was not a picnic. NOT a picnic! But it was a walk on the park, so to speak.
And I definitely wouldn't let myself go out of shape like that again thinking it would be an easy ride home. Basically I stomped my A1C almost in half, from 50 (knocking on the door of diabetic) down to 30 (complete remission to decent health) - so totally mullahed it. Doc says that's at the limits of medical science, so I was pretty chuffed. Need to maintain now with IF and regular workout.
What it cost me was:
IF, 12 or 18 hour sessions once (occasionally twice) per week.
Diet change to 80% plant based, more raw veg, nuts, fish
Setting a reminder to drink water
Walking 20 miles twice a week with a full pack (that's where most people will wobble a bit).
Cold water sea swimming (you get used to it)
I added two tricks. One is to walk on sand. Other is replace lost weight by stuffing a modular armour jacket with little sand bags in the plate pockets. When I dropped from 95kg to 90kg I just added 5 kilos of sand and so on. This happens gradually. When you carry around the weight you lost it keeps the calorie burn the same per mile and really motivates you because you can literally feel how much lighter you are when you take the vest off. Also you can just drop weight if you get exhausted on a long yomp.
Yes I am lucky too. I live in a place with opportunity for outdoor activity. Probably good metabolic genetics. Made time to do the health work by dropping some contracts (I consider it an investment in myself like college etc) Also I took the diagnosis seriously and researched an action plan.
Oh yea for sure. I understand that you put in a lot of effort for the results that you mentioned.
> The doc basically said my latest bloods are outstanding
But I am not clear if you've had any lasting damage from the past or is everything is simply reversed. Is there anything that cannot be reversed with any amount of effort?
>Then what would be the point of living a healthy lifestyle everyday if you can simply 'get healthy' in a matter of months when you need it.
Because the labs are just indicators of whether or not damage is being done.
If you have high LDL for example, disease state is correlated to how long, and how high LDL levels have been. (The evidence for that is robust.) So for example, while you can improve those levels in 6 months, that doesn't mean you weren't racking up damage for the previous 10 years.
This is a common thing with most health indicators actually: blood pressure, LDL, blood sugar, etc. End organ damage, and risk of adverse events are correlated to how high and how long levels were maintained.
> that doesn't mean you weren't racking up damage for the previous 10 years.
> and risk of adverse events are correlated to how high and how long levels were maintained.
Is there a way to measure this though. How can I tell what my current level of damage is.
GP got the usual indicators into shape. Is all the 'racking up damage' reversed in OPs case ?
I find macro timing/restriction to be better in combating "hangryness", meals before 10am and after 4pm are protein and carb heavy and anything in between is higher protien and low or near zero carb. I used to 16:8 and 18:6 IF but Id just be too moody.
What's the IF protocol do you use? And do you take any Coffee during fasting? Any sugar or milk?
A few researchers, notably Alan Aragon and Brad Schoenfeld did a lot of analysis on protein timing research a while back and the general conclusion is that as long as you get enough protein during the course of the day (or within a few hours of your workout), basically it doesn't matter so much.
Aragon, Alan Albert, and Brad Jon Schoenfeld. “Nutrient Timing Revisited: Is There a Post-Exercise Anabolic Window?” Journal of the International Society of Sports Nutrition 10 (January 29, 2013): 5. https://doi.org/10.1186/1550-2783-10-5.
Schoenfeld, Brad Jon, Alan Aragon, Colin Wilborn, Stacie L. Urbina, Sara E. Hayward, and James Krieger. “Pre- versus Post-Exercise Protein Intake Has Similar Effects on Muscular Adaptations.” PeerJ 5 (January 3, 2017): e2825. https://doi.org/10.7717/peerj.2825.
Schoenfeld, Brad Jon, Alan Albert Aragon, and James W Krieger. “The Effect of Protein Timing on Muscle Strength and Hypertrophy: A Meta-Analysis.” Journal of the International Society of Sports Nutrition 10 (December 3, 2013): 53. https://doi.org/10.1186/1550-2783-10-53.
Schoenfeld, Brad Jon, and Alan Albert Aragon. “How Much Protein Can the Body Use in a Single Meal for Muscle-Building? Implications for Daily Protein Distribution.” Journal of the International Society of Sports Nutrition 15 (February 27, 2018). https://doi.org/10.1186/s12970-018-0215-1.
There are some interesting wrinkles (like Leucine intake in particular), and I'd recommend looking at what Stuart M Phillips and Donald K Layman have published as additional places to spelunk from for anyone that's particularly interested in the topic.
This makes more sense than "you have to eat protein within one hour from exercising". Why? Because wouldn't it take a lot longer for the protein to get digested in your body? Possibly many hours, depending on the source of protein. And if, after exercising, I'm still digesting protein I've eaten several hours earlier, what difference can it make if I add some more that will just get digested several hours later, provided that the total amount of protein is kept constant.
This has mostly arrived in the consensus of sports training. General advice is to have protein surplus in the 24 hours after training (if you train every day, like an athlete, that means every day).
Plus if you're training but want to lose at the same time, you need a caloric surplus for a while to have your muscle regenerate and grow, but it's totally possible to gain muscle and lose weight at the same time. But basically each calory that you're in deficit will make your muscles grow more slowly, so it's definitely harder than being on an overall surplus.
Yes Don Lyman's research has shown the same thing. Timing of protein consumption doesn't matter very much. The important thing is to consume a large bolus of at least 40g during a single meal rather than spreading it out in little snacks throughout the day.
After doing a 4 hour eating window for years eating at around maintenance and had some cheat meals over the weekend. It kind of kept my weight stable but my strength hardly increased so seems my anecdotal experience kind of seems to match that report.
I also heard somewhere it could take like 24~48 hours for all protein sources to be digested and extracted from your bloodstream so you might have like a constant amino acids drip into your bloodstream but i never really checked this.
I'll assume that your goal when drinking a protein shake/gaining muscle is to gain muscle. It's generally believed that a state of anabolism is generally viewed as being antagonistic to the body; too much protein/growth is taxing. Yet, having muscle is important for aging, and also acts as a glucose sink thereby improving metabolism. A balance has to be achieved.
> Or is this less important than the immediate-protein-shake crowd suggests?
From what I've read, this may be not as important as originally thought.
Overall, I believe the schedule that most holistically supports metabolism would be to exercise early and also eat early in the day. This would thereby keep the taxing metabolic activities aligned to your circadian clock, which expects a lot of early day stressors and fewer as the day progresses. This may be specifically true for protein which is especially metabolically taxing, so eating it early in the day is probably the time when it creates the most benefit at lowest risk.
Of course, people have to do what works for their schedules and lifestyles.
> exercise early and also eat early in the day
This is slightly contrary to what I’ve learned from Rhonda Patrick. Exercise in the morning, sure, but while still fasting from overnight (black coffee or plain tea ok… does not break the fast).
Eat after exercise so that your fast lasts longer. Also, cardio exercise blunts the hunger feeling in many people.
Here’s a piece of COMPLETELY anecdotal data, so do with it what you will. A friend with metabolic syndrome was struggling with weight despite intermittent fasting. She began to wear a continuous glucose monitor. She found that black coffee had the same effect as eating a donut, but if she added a boiled egg, the effect on her glucose was neutral.
Now, I don’t know what effect all that has on other metabolic processes. I doubt the effect is universal. But it is interesting that the revived wisdom about black coffee being okay is not universally true.
This has been my schedule for my entire adult life, not because I read it, but simply because it felt the "best" for myself. I was never a big breakfast eater anyway, and I found fasted + black coffee exercise the best for myself personally in terms of energy, motivation and so on.
Yeah I'm not suggesting an order between the two. I think everything held constant, eating earlier is supposed to be better. I don't think there have been many studies where people stop eating at like, 10am, or something like that. That said, I think most studies that have shown benefit are those where people have like a 4-8 hour eating window from 6am-2pm, or are of that order.
But is there a difference between having your day's large meal at 8am or 11am? Those are both pretty 'early', so it might not matter; I don't think we know. However, as the day winds on, more data comes to light which suggests that earlier is better.
If your goal is muscle gain, you need some glucose available during the workout to maximize the weight you can lift.
Proteins have 4 calories per gram so if your usual post-workout protein intake would be 20-30g, it'd be 80-120 calories. YMMV but that would move me out of fast. The only calories I ingest during the fast is a little fat for vitamin D bioavailability in the morning.
My caloric window is 1-8pm and I exercise in the mornings with just a few essential amino-acids.
Not sure, but isn't 20-30% of the protein lost in digestion?
Protein thermic effect is 30% so amount of calories equal to ~30% of that coming from protein is burned to digest protein. You're burning calories, not protein, to digest protein. Those calories are already stored and don't necessarily have to come from protein digestion.
No. I do IF and lift heavy+cardio every early morning. I have progressively gotten stronger - benching over 330 and squatting well into the 400s.
Ive spent a lot of heartache and headache over research around these type of questions. The best answer is to learn what works best for your own body. Eat enough protein as a starter in any case.
I can't comment on fasting in particular, but as another comment pointed out, I think the idea that you need to immediately get protein before/during/after a workout is a bit overblown.
My understanding is that protein can be rate-limiting for hypertrophy if you don't have enough in general, but timing is not as largely important. I believe there is a rough window for anabolic signaling / net-positive muscle protein synthesis that lasts up to 48 hours after exercise
The 'anabolic window' has largely been disproven. Depending on your goals though, from a resistance training perspective you typically need to be in a caloric surplus (although not an excessive one) to put on muscle.
You have to time the eating accordingly. I find I don't feel terrible if I lift prior to breaking the fast. And boy does that food taste good.
Sauna seems pretty close, it’s just sitting somewhere hot on a regular basis and is quite pleasant.
Saw a study recently that showed broad, dose dependent health effects.
Personally it really seems to help when I’m overloaded with stress, in a direct immediate way.
Well, to get the full benefit you also want the ice bath afterwards.
Sauna is fun, but it's not a panacea. It can't replace exercise, for example.
It screws up your semen.
Or fixes it depending on your life goals
Most men have only about a 10-year period when they care about their semen quality, you can use the sauna the other 50 years.
Don't sauna in the few days before you plan to conceive. Bikes, among other things, can also screw up your semen. It's not that uncommon, and it's only temporary
Which reverses when you stop.
Great male contraceptive ;-)
What about testosterone?
I remember reading that the reason that many doctors prescribe pills over a lifestyle change is that it is significantly easier to gain compliance.
I can imagine it's kind of like being a parent or manager. After advising perfect behavior and rarely getting it, you give up and settle for easy, less perfect but achievable advice.
> doctors prescribe pills over a lifestyle change
does doctors prescribing lifestyle change have any noticeable effects though. I assume everyone already knows they need to 'eat better and exercise'. I am not convinced that doctor telling them this will finally make it sink in for anyone.
Also, most doctors have layman level understanding of nutrition and excercise and many of them are not in best shape themselves.
I am the same way, except I just cream. Every time I have come across a discussion on this topic of having cream in your coffee while trying IF, the anecdata consensus is that any calories at all break your fast, so you are no longer fasting if you consume a small amount of cream/sugar.
Having said that, I still do 18/6 IF with cream in my coffee and in my personal experience I still feel great and have had many positive benefits from continuing IF.
Ignore the bro science. Keep your cream, though you should probably drop the sugar.
I limit my coffee creamers to about 25-100 calories depending on number of cups pre-meal. I’m in better shape than most hardcore IF practitioners.
It is just how devolved our modern eating habits are, we are constantly snacking or eating garbage which makes us hungry soon after. Three solid meals a day, cooked at home with unprocessed food ought to be good enough to live a healthy life but for the people who go on all sorts of diets, food has long become an emotional thing so they need restrictive frameworks in place to help them not eat so much/eat junk food. I bet our ancestor never thought this hard about what to eat and when to eat.
Not sure how this study was designed; but it's been replicated probably dozens or hundreds of times that circadian-based eating schedules confer the best metabolic benefits. That is, the earlier the eating, the better the metabolic benefit. Although I have seen some data that suggests you should wait one hour before consuming your first meal (as you should wait for the cortisol spike from waking to taper).
No, all your eating happens in that 10 hour window. You fast for at least 14 hours per day. Easy enough if you eat an early dinner and don't snack after.
Is the position of that window relevant?
So, I sleep 9h, which means, I'm awake 15h.
If I don't eat 2,5h before and after sleeping, would this be enough?
> Is the position of that window relevant?
This seems like one of the things that makes it hard to test intermittent fasting: there are a bunch of variables other than just the length of the window.
> If I don't eat 2,5h before and after sleeping, would this be enough?
Some researchers think so, yes. I don't think anyone knows what is optimal. Research is ongoing.
so lunch AND dinner or just early dinner? always feel like these hourly windows are underspecified since you can cram a ton of food in that time
If it's a 10 hour window presumably most people are eating multiple meals, but it's not really underspecified since you can eat whenever you want during that time.
There are other people doing 4 hour windows for IF in which case it's more like a single meal, but that's not what this study tested.
(This is just explaining the idea, not advocating IF)
You are missing key informations here (see below). The study you linked is on obese people primarily aiming for weight loss, it’s absolutely not of good quality for judging IF because calories and protein intake are not matched between the groups, it’s more a study of if IF gives better satiety. Not really comparable to the one randomized on firefighters discussed here, which is of better quality overall especially for IF health benefits (main vs secondary objective in your linked study, randomized not only on obese people, no difference in meal compositions between groups) and so directly contradicts the decision of the lead researcher you cited to quit IF.
From the study you linked:
> Participants were randomized such that the consistent meal timing (CMT) group was instructed to eat 3 structured meals per day, and the time-restricted eating (TRE) group was instructed to eat ad libitum from 12:00 pm until 8:00 pm
> A follow-up study showed that when calorie intake and protein intake were matched to prestudy consumption, no change in lean mass was observed.
> Ad libitum feeding during TRE leads to reduced calorie intake and might also reduce protein intake.9 Together, these data highlight the importance of adequate protein consumption while adhering to a TRE diet. Many studies have shown that adequate/excessive protein consumption during weight loss can mitigate losses in lean mass.
> the IF group saw no excess weight loss or cardiometabolic benefits vs. the continuously calorically restricted control
It may be the case that these two processes lead to similar outcomes. But for me, it is much easier to stay faithful to an IF lifestyle than a "continuously calorically restricted" lifestyle. I find the binary aspect of the IF system to be very helpful. If the other system is easier for other folks to maintain, that's great, and they should do that.
But the fact that IF doesn't lead to better results than a different system doesn't mean that people who practice IF are clinging to an idiotic practice, as you put it.
> It may be the case that these two processes lead to similar outcomes. But for me, it is much easier to stay faithful to an IF lifestyle than a "continuously calorically restricted" lifestyle. I find the binary aspect of the IF system to be very helpful. If the other system is easier for other folks to maintain, that's great, and they should do that.
In the 8-16 IF study I linked to, the IF/TRE group actually had worse adherence:
> Self-reported adherence to the diets was 1002 of 1088 (92.1%) in the CMT group (did not miss any meals) and 1128 of 1351 (83.50%) in the TRE group
The fact that more people couldn't adhere to an IF plan than a the other plan isn't really relevant. It's easy for someone (like me) to be able to ascertain if it I am able to stick to IF, so it doesn't matter if other people find it harder. Like I said, if other people find the other plan easier to do, and also effective, then it makes sense for them to do it. I don't understand the name-calling, as if no rational person could choose IF.
I feel more awake when fasting. I feel sluggish and hungry if I eat breakfast. It's not ridiculous to skip breakfast. How is that idiotic ? I have top health markers for my age and do a variety of different types of physical sports. I think the old adage (still popular among powerlifters and bodybuilders) to eat every 3-4 hours to be completely stupid. We never evolved like that, it's a luxury modernity that this is even an option.
> We never evolved like that, it's a luxury modernity that this is even an option.
That's the brainletism I was referring to. You could have easily verified your assumption by looking at remaining hunter-gather populations, who serve as a good proxy for you ancestors, and had you done that, you would have discovered that--surprise, surprise--they don't fast:
You're overly confident in your tone and thin on details (and a written link goes further than a YouTube reference).
How in the world is a remaining hunter gatherer population in 2022 a proxy for what happened tens of thousands of years ago. That's an assumption you're expected to justify, first off.
Secondly, how is food abundance being modern a 'brainletism' or whatever you're enjoying repeating as a sort of provocation.
So IF lost just as much weight as normal dieting. Are you unable to comprehend it that way?
I mean, what weight was lost seems extremely important... let's say you lost the "as much weight" because your foot fell off... would that make the distinction more clear?