> protein pacing diet for the remaining five/six days/week (Protein pacing refers to 4–6 meals/day evenly-spaced, where each meal contains 25–40g of protein)
> During fasting days, participants fasting for one day/week were allowed to consume 400 Kcal/day, while participants fasting for two consecutive days were allowed 500 Kcal/day. During non-fasting days the dietary regimen provided 1350 and 1700 kcals/day for women and men, respectively, and a macronutrient distribution consisting of 35% protein, 35% carbohydrate, and 30% fat.
That's somehow more calories/day than I would expect for a "fasting day", and fairly restrictive over-all. I'd be curious to hear how these compare to someone on the 1350/1700 kcal/day diet 7 days a week.
> Extending beyond 4-weeks reduces compliance and may be overly excessive for a caloric restriction and 2 day IF and create undue metabolic, physiologic, hormonal, and psychological stress in the study participants.
Also something I was wondering, the repeated emphasis on short-term benefits has me wonder how the participants did after the trial. Does it do much good if you drop more but it bounces back?
> Isagenix International, LLC (Gilbert, AZ, USA) provided all meal replacement shakes, bars, beverages, and supplements.
> Whole Blend IsaLean® Shakes, Cleanse for Life®, Ionix® Supreme, Collagen Bone Broth, AMPED™ Hydrate, Harvest/Whey Thins™, IsaDelight® Chocolates,
> This study was supported by a grant (IRB#: 1911–859) from Isagenix International, LLC
> P.J.A. (the primary author) is a member of the scientific advisory board at Isagenix International LLC, the study’s sponsor. E.G. and A.E.M. are employed by Isagenix International LLC.
Assuming 2000 kcal/day is the normal amount blah blah blah.
For men, they are running a 300 kcal deficit for 5 days and 1500 kcal deficit for the other two. For a total of 4500 kcal per week. Or losing about a pound and a half.
Now, seeing as this is for overweight people, it's likely to be even more. As it takes more calories per day to maintain higher weights. So if the person's maintenance is about 3000 kcal/day, that's going to be a deficit of roughly 11,500 kcal per week. Which is close to 4 pounds.
But then again, restricting yourself to just 2000 kcal/day would have you lose about a pound and a half per week.
Because, when you are very overweight, lots of things work.
Study is definitely suspect, but if 400-500 kcal allowed for the benefits of fasting that would be really useful information for some. I have to eat some food for medication in the morning, and have always presumed that made fasting not a viable strategy for me.
On average, sure, but there are plenty of metabolic outliers, and I doubt those seeking weight loss are on the higher end. My weight was surprisingly consistent at 1300kcal/day.
> Also something I was wondering, the repeated emphasis on short-term benefits has me wonder how the participants did after the trial.
This right here is the first and most important reason to be skeptical of any study on weight loss. None of these things ever turn out to do anything useful on a time horizon that matters.
If you want to know how to lose weight for a few weeks you don't need a peer reviewed journal, just go get a "women's health" magazine and read about several ways that really do probably work to lose weight in that timespan.
Aside from what others have pointed out that it's perfectly okay for a scientific study to have limited scope and not try to solve the entire problem of how to lose weight and keep it off, which inherently requires following and monitoring people for a very long time, even the case you're describing here isn't necessarily all bad.
Given a person undergoes an intervention, succeeds in losing 40 pounds, then gains it all back over the next five years, that sounds like failure in a vacuum, but that means they spent five years not gaining more weight. If the non-intervention counterfactual is they would have ended up 40 pounds even heavier, then intervention is still a win. Yo-yo dieting with lifetime net zero progress is still better than steadily getting fatter for the rest of your life.
> This right here is the first and most important reason to be skeptical of any study on weight loss. None of these things ever turn out to do anything useful on a time horizon that matters.
It's (always) worth skimming the article, or at least the headline. From the subheadline:
> *Given the same energy intake and expenditure*, intermittent fasting two days versus one day per week increases weight loss in overweight men and women
This study isn't saying "2 day IF is a miracle weight-loss cure and you should just do it bada bing bada boom weight loss solved". It's holding everything constant except the number of fasting days, and finding that it's (quite dramatically) more effective in the short-term.
This is a data point, not a weight-loss plan. It doesn't call for "skepticism", just careful reading and limited application (or for a start, reading the article/headline at all).
Nutrition is intensely complicated and devilishly difficult to study. But for scientifically-literate people who take it seriously, data points like this shed light on limited portions of the "solution space". This is crucial to mapping out the space enough to understand how to improve your own diet; it's not amenable to an impatient approach that expects every study to be a magic bullet.
Even ignoring the signal that this provides, the absolute minimum value of this study is that somebody who's already doing a time-limited IF-1 diet can switch to a time-limited IF-2 diet. That's valuable in and of itself.
> If you want to know how to lose weight for a few weeks you don't need a peer reviewed journal, just go get a "women's health" magazine and read about several ways that really do probably work to lose weight in that timespan.
With the same improvement in hunger levels, hormone profile, and cardiometabolic health (all mentioned in the for both the control and treatment)? I highly doubt it. Even assuming that IF isn't sustainable[1], people do have short-term weight loss goals sometimes, and IF provides a path to do so that keeps metabolic and hormonal health in mind relative to traditional crash dieting.
[1] I've been doing it for....five years now? Not only did I lose a reasonable amount of weight early on, it's been helpful for maintaining during a life phase of suddenly-expanding waistlines among my peers. Plus it's trivial to dial it up slightly when I do feel the need to tighten up a little.
Having water fasted many times, I swear this has something to do with burning all the stored glycogen. I have no backing other than what I’ve experienced myself. I get really hungry for a week after a fast and continue to lose weight or stay the same. Anecdotally, I’ve chalked this up to as long as your glycogen bank isn’t full, you can pretty much eat whatever you want. Water fasting is glorious btw.
To add some numbers - your liver and muscles store about 500g or 2000 calories of glycogen. Each gram of stored glycogen is bound to 4 grams of water, for a total of roughly 2.5kg / 5lbs of weight.
When you eat in a calorie surplus, your glycogen stores are full. When you eat in a sustained deficit, you operate with very low glycogen stores.
This is why when you start a diet you often immediately lose 5 pounds in the first few days.
This is also why when you are dieting and have a huge cheat meal, you "gain 5 pounds" and then lose it again immediately upon resuming your diet. It's mostly retained water since your body converts the giant influx of calories into glycogen then burns it off over the next several days.
For anyone considering zero-calorie fasting for more than 1 day, please read up on it first. Pay special attention to the need for salt. You need to start every day of the fast with a glass of saltwater, on the order of 3 teaspoons of salt. If you take hot baths, you will perspire and need more salt. Take a glass of saltwater to the tub with you. Because if you sweat in the tub there is a good chance walking to the kitchen will be a panic-inducing challenge. Also, it is best to do extended fasts, at least after day 3, on vacation/holiday. You may not feel like doing much.
Could you elaborate a little about your regimen? Each time I attempted water fasting, the next day I was basically famished ( and needless to say, any progress made was lost ).
I would drink water for 5 days. It's not too difficult. The hardest part is the boredom. I'm quickly reminded how much of my life revolves around food. Farmers market, grocery shopping, happy hours, cooking dinner, work lunches, events, etc. You suddenly have all this free time. For me, I just play a lot of golf to take my mind off of it.
If you want an easy version, look up fast mimicking diet by Dr. Longo. Prolon sells premade kits.
Have you tried fasting for 20 hours and only eating during a 4 hour window? That seems to work well for me. The first few days I was hangry but pretty used to it now. Biggest change in my lifestyle was switching to black coffee in the morning as you can't consume any calories during fasting. This is the paper that inspired me to do this:
In my experience, the first day is by far the most difficult. I find that it's most effective to start fasting on days where I am going to be occupied with something, since I don't think about food when I'm active.
I'd be miserable if I attempted to fast on a day where I was lounging around watching TV.
I have the same question. Specifically, for a fast lasting longer than 24 hours, is any supplement taken? What side effects occur?
I did Paleo in 2012 for several months with success. However, I have tried Keto/low carb again several times with less success. Specifically with Sated meal replacement. I get muscle cramps and other side effects that I assume are due to changes in the diet.
> During fasting days, participants fasting for one day/week were allowed to consume 400 Kcal/day, while participants fasting for two consecutive days were allowed 500 Kcal/day. During non-fasting days the dietary regimen provided 1350 and 1700 kcals/day for women and men, respectively
That seems like the first claim is just untrue and the 2-day-fasters are consuming fewer calories overall? If all the non-fasting days are the same for both groups like this says, then the 2-day-fasting men are consuming 1100 fewer calories per week (and 750 fewer for women). Even if intermittent fasting did nothing at all, I would expect that extra calorie deficit to result in more weight loss.
A proper methodology would be to have all 3 groups consume the same 7-day baseline diet for 2 weeks, then switch into the IF groups and monitor increases in rate-of-change for body weight vs net body weight difference before/after. There should also be similar caloric input for all groups before and after program to see if there is actually an additional benefit to intermittent fasting vs caloric input reduction.
They use the term "eating freely" which to me would imply the option to consume nothing but popcorn and McDonalds. Or at least the option to eat as many calories as desired.
To have a caloric restriction below 2000 per day is a restricted diet to me - not that that's bad.
Yeah, and having a single number makes no sense because on average men and woman have different requirements. I live a well above average active lifestyle and my maintenance is in the ballpark of 1400/day.
The reason why intermittent fasting works is that it is associated with increased oxidation of fatty acids (lipolysis) and ketone body formation (ketogenesis), activated cell-signaling pathways (insulin sensitivity, reduced inflammation, autophagy), and preservation of lean body mass, known as “metabolic switching”.
The interesting fact however is that typically, these mechanisms are not fully activated until at least 24 hours of fasting.
Well, this sounds to me like they know it has an effect but they don't actually know the full story on why it works.
Yeah, but my point is that IF is generally under 24 hours, yet has an effect. So they seem to not have a good explanation for why IF helps given that their hypothesis fits what we know happens after the 24 hour mark and you aren't doing that.
"We know it works because after 24 hours, X happens" does not explain why it works when you aren't hitting that mark. Sorry.
One should note that the participants (N=20) were divided into two groups with the respective regimens, and put on a controlled calorie diet for the rest of the time. Evaluation was after four weeks.
This study tells us very little. Small sample size, constrained diets without a proper control (protein pacing without IF, or no restriction at all), short evaluation horizon.
There could be something to it, but as they say, that requires a lot of further study. In itself this study provides a hint, certainly nothing close to an authoratative conclusion.
If someone can make it so it doesn't feel like I can no longer think or move any muscles or start sweating if I go more than about 3 hours without eating, then I'm on board! Also hunger pangs. Please no.
Yeah unfortunately I’ve had these symptoms throughout my life, have been regularly checked for diabetes but no dice. My dad has type 1 so we recognised my symptoms, but apparently it isn’t diabetes.
Readit News
> During fasting days, participants fasting for one day/week were allowed to consume 400 Kcal/day, while participants fasting for two consecutive days were allowed 500 Kcal/day. During non-fasting days the dietary regimen provided 1350 and 1700 kcals/day for women and men, respectively, and a macronutrient distribution consisting of 35% protein, 35% carbohydrate, and 30% fat.
That's somehow more calories/day than I would expect for a "fasting day", and fairly restrictive over-all. I'd be curious to hear how these compare to someone on the 1350/1700 kcal/day diet 7 days a week.
> Extending beyond 4-weeks reduces compliance and may be overly excessive for a caloric restriction and 2 day IF and create undue metabolic, physiologic, hormonal, and psychological stress in the study participants.
Also something I was wondering, the repeated emphasis on short-term benefits has me wonder how the participants did after the trial. Does it do much good if you drop more but it bounces back?
> Isagenix International, LLC (Gilbert, AZ, USA) provided all meal replacement shakes, bars, beverages, and supplements.
> Whole Blend IsaLean® Shakes, Cleanse for Life®, Ionix® Supreme, Collagen Bone Broth, AMPED™ Hydrate, Harvest/Whey Thins™, IsaDelight® Chocolates,
> This study was supported by a grant (IRB#: 1911–859) from Isagenix International, LLC
> P.J.A. (the primary author) is a member of the scientific advisory board at Isagenix International LLC, the study’s sponsor. E.G. and A.E.M. are employed by Isagenix International LLC.
Ok, that reads as very suspect, now.
For men, they are running a 300 kcal deficit for 5 days and 1500 kcal deficit for the other two. For a total of 4500 kcal per week. Or losing about a pound and a half.
Now, seeing as this is for overweight people, it's likely to be even more. As it takes more calories per day to maintain higher weights. So if the person's maintenance is about 3000 kcal/day, that's going to be a deficit of roughly 11,500 kcal per week. Which is close to 4 pounds.
But then again, restricting yourself to just 2000 kcal/day would have you lose about a pound and a half per week.
Because, when you are very overweight, lots of things work.
This right here is the first and most important reason to be skeptical of any study on weight loss. None of these things ever turn out to do anything useful on a time horizon that matters.
If you want to know how to lose weight for a few weeks you don't need a peer reviewed journal, just go get a "women's health" magazine and read about several ways that really do probably work to lose weight in that timespan.
And then you gain it back.
Given a person undergoes an intervention, succeeds in losing 40 pounds, then gains it all back over the next five years, that sounds like failure in a vacuum, but that means they spent five years not gaining more weight. If the non-intervention counterfactual is they would have ended up 40 pounds even heavier, then intervention is still a win. Yo-yo dieting with lifetime net zero progress is still better than steadily getting fatter for the rest of your life.
It's (always) worth skimming the article, or at least the headline. From the subheadline:
> *Given the same energy intake and expenditure*, intermittent fasting two days versus one day per week increases weight loss in overweight men and women
This study isn't saying "2 day IF is a miracle weight-loss cure and you should just do it bada bing bada boom weight loss solved". It's holding everything constant except the number of fasting days, and finding that it's (quite dramatically) more effective in the short-term.
This is a data point, not a weight-loss plan. It doesn't call for "skepticism", just careful reading and limited application (or for a start, reading the article/headline at all).
Nutrition is intensely complicated and devilishly difficult to study. But for scientifically-literate people who take it seriously, data points like this shed light on limited portions of the "solution space". This is crucial to mapping out the space enough to understand how to improve your own diet; it's not amenable to an impatient approach that expects every study to be a magic bullet.
Even ignoring the signal that this provides, the absolute minimum value of this study is that somebody who's already doing a time-limited IF-1 diet can switch to a time-limited IF-2 diet. That's valuable in and of itself.
> If you want to know how to lose weight for a few weeks you don't need a peer reviewed journal, just go get a "women's health" magazine and read about several ways that really do probably work to lose weight in that timespan.
With the same improvement in hunger levels, hormone profile, and cardiometabolic health (all mentioned in the for both the control and treatment)? I highly doubt it. Even assuming that IF isn't sustainable[1], people do have short-term weight loss goals sometimes, and IF provides a path to do so that keeps metabolic and hormonal health in mind relative to traditional crash dieting.
[1] I've been doing it for....five years now? Not only did I lose a reasonable amount of weight early on, it's been helpful for maintaining during a life phase of suddenly-expanding waistlines among my peers. Plus it's trivial to dial it up slightly when I do feel the need to tighten up a little.
I found IF gave me a tool to help me control my appetite for the rest of my life.
Self control is best method for maintaining weight, as it's free and guaranteed to work if used.
Deleted Comment
When you eat in a calorie surplus, your glycogen stores are full. When you eat in a sustained deficit, you operate with very low glycogen stores.
This is why when you start a diet you often immediately lose 5 pounds in the first few days.
This is also why when you are dieting and have a huge cheat meal, you "gain 5 pounds" and then lose it again immediately upon resuming your diet. It's mostly retained water since your body converts the giant influx of calories into glycogen then burns it off over the next several days.
If you want an easy version, look up fast mimicking diet by Dr. Longo. Prolon sells premade kits.
https://www.nejm.org/doi/full/10.1056/nejmra1905136
In my experience, the first day is by far the most difficult. I find that it's most effective to start fasting on days where I am going to be occupied with something, since I don't think about food when I'm active.
I'd be miserable if I attempted to fast on a day where I was lounging around watching TV.
I did Paleo in 2012 for several months with success. However, I have tried Keto/low carb again several times with less success. Specifically with Sated meal replacement. I get muscle cramps and other side effects that I assume are due to changes in the diet.
> During fasting days, participants fasting for one day/week were allowed to consume 400 Kcal/day, while participants fasting for two consecutive days were allowed 500 Kcal/day. During non-fasting days the dietary regimen provided 1350 and 1700 kcals/day for women and men, respectively
That seems like the first claim is just untrue and the 2-day-fasters are consuming fewer calories overall? If all the non-fasting days are the same for both groups like this says, then the 2-day-fasting men are consuming 1100 fewer calories per week (and 750 fewer for women). Even if intermittent fasting did nothing at all, I would expect that extra calorie deficit to result in more weight loss.
I think that the logic of giving even less to those fasting is pretty obvious that it would lead to more weight loss.
You can read the full study here, but it seems to confirm a caloric defecit on the IF2 and IF group vs control.
https://nutritionj.biomedcentral.com/track/pdf/10.1186/s1293...
...
IF1-P, 9058±692 kcals/week vs.
IF2-P, 8389±438 kcals/week
A proper methodology would be to have all 3 groups consume the same 7-day baseline diet for 2 weeks, then switch into the IF groups and monitor increases in rate-of-change for body weight vs net body weight difference before/after. There should also be similar caloric input for all groups before and after program to see if there is actually an additional benefit to intermittent fasting vs caloric input reduction.
To have a caloric restriction below 2000 per day is a restricted diet to me - not that that's bad.
I'm literally twice the size of my friend, at the same BMI (more than a foot taller). So should I be eating 3400? Or should they be eating 850?
You're supposed to:
- count your calories and maintain the same calorie intake for a while
- measure your body weight or other metric you want to change throughout
So, if you're eating 2,500 calories a day and see you're gaining weight, you have a baseline you want to go below to lose weight.
The interesting fact however is that typically, these mechanisms are not fully activated until at least 24 hours of fasting.
Well, this sounds to me like they know it has an effect but they don't actually know the full story on why it works.
"We know it works because after 24 hours, X happens" does not explain why it works when you aren't hitting that mark. Sorry.
This study tells us very little. Small sample size, constrained diets without a proper control (protein pacing without IF, or no restriction at all), short evaluation horizon.
There could be something to it, but as they say, that requires a lot of further study. In itself this study provides a hint, certainly nothing close to an authoratative conclusion.
N=10 in each group, and the IF-2 day group has a single clear outlier (someone who is obviously larger than everyone else).
If so, it might be a good idea to go and check your blood sugar.