Thoughts on the 5:2 fasting method?

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GabrielleCote
GabrielleCote Posts: 10 Member
in Health and Weight Loss
For those of you who don't know what it is, it's eating at maintenance calories 5 days a week, and fasting on only a quarter of those calories 2 days a week (usually comes to about 500 calories for women and 600 calories for men).

Currently I'm eating 1400-1500 calories/day giving me a ~2170 weekly calorie deficit and not eating my exercise calories back (1 hour resistance training or moderate pace walking/super slow jogging, 3-5 times/week). I do not plan on changing my exercise regime.

Using the MFP model for calorie intake, in a 5:2 fasting system it would be 1760 calories 5 days : 440 calories 2 days, leaving me with a 2640 weekly calorie deficit. Using the TDEE model for calorie intake, in a 5:2 fasting system it would be 1958 calories 5 days : 490 calories 2 days, leaving me with a 3556 weekly calorie deficit.

So essentially the weekly caloric deficits fall between the weekly MFP and TDEE deficits of the daily deficit model. Maybe not neccessarily indefinitely, but I know I can handle one 450 calorie meal a day twice a week if I time it on days where I don't exercise. Additionally, I like the idea of having room for a calorie dense treat 5 days a week without having to forcefully keep my calories low.

How do you guys feel about this 5:2 fasting method? My main concern is losing muscle mass because my body will resort to breaking down muscle (along with fat) even if I'm not really active on fasting days. Some say it can be combat with plenty of dietary protein... I know I can lose weight but can I still build muscle starving my body two days a week, or is preserving it even a pipe dream? Any personal experiences or opinions with other aspects of the diet?

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  • TimothyFish
    TimothyFish Posts: 4,925 Member
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    I don't see any reason for concern. We carry the food we eat around in our guts for about two days after we eat it, so skipping a day isn't going to make much difference in what nutrients are available to our system.
  • TeaBea
    TeaBea Posts: 14,517 Member
    edited June 2015
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    A couple of group links.......

    http://community.myfitnesspal.com/en/group/100058-5-2-fasting

    http://community.myfitnesspal.com/en/group/49-intermittent-fasting

    I've tried this. My goal was to get away from logging (didn't work for me)...the logging part....not the losing part. Anyway, most people don't build any muscle while eating at a deficit. My hope is just to maintain it.
  • smotheredincheese
    smotheredincheese Posts: 559 Member
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    I did the 5:2 for a couple of months at the start of the year. It started off well and I did initially lose weight but over time I started to find it very hard to stick to 500 calories on my fast days, I was starving all the time and couldn't do any exercise on those days. In the end I ended up getting so hungry I would have massive binges in the evening and go way over the 500 calories. It can be much harder than you think.
    I know people who have been doing it for years though and swear its the only thing that's ever worked for them, so my experience definitely isn't universal.
  • juggernaut1974
    juggernaut1974 Posts: 6,212 Member
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    For some people it works great and fits their lifestyle. Others it doesn't.

    It's no more or less magical than any form of creating a calorie deficit.

    If it's something you think would fit your lifestyle, go for it. If you think it would be hard and difficult for you, I'd suggest an alternative approach.
    GabrielleCote wrote: »
    I know I can lose weight but can I still build muscle starving my body two days a week, or is preserving it even a pipe dream? Any personal experiences or opinions with other aspects of the diet?

    As a general rule, the two goals are diametrically opposed.

    To 'gain muscle' you'll need to be an a caloric surplus, not deficit. Generally, while losing weight preserving as much existing muscle mass as possible is the goal, and is accomplished by regularly lifting. The type of eating plan won't affect it in any significant way.

  • ibamosaserreinas
    ibamosaserreinas Posts: 294 Member
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    I really like the Leangains/16:8 method better. I stop eating at night at 8:00 pm. I skip breakfast and eat lunch at 12:00. I do that Monday - Friday and take Saturday and Sunday off.

    I haven't read up on the "science" behind it enough to see if it is legit or not. I simply do IF because it helps me manage my deficit more comfortably. Losing at about 1.5 lbs a week my calorie allowance is only about 1370/daily. I prefer to eat a nice big lunch, and dinner.
  • GabrielleCote
    GabrielleCote Posts: 10 Member
    edited June 2015
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    TimothyFish, doesn't the type of food have an effect on length of digestion? For example proteins take longer to digest than carbs?

    TeaBea, thanks for the links! Will definitely poke around and find some information. I have on other sites but was afraid it might be biased...

    smotheredincheese, I am curious about different ways to keep a handle on my calorie deficit, but if it causes me to binge than this method won't help and I'll go back to my current method. I expect many people have had similar experiences to you, also, so thank you for your input!

    ceoverturf, so what you're saying is a deficit makes it hard to build muscle (which I know) but individual daily deficits don't make any more of a difference than overall deficits? Because that is my main concern.

    ibamosaserreinas, there are two reasons I hadn't seriously considered this method. Firstly, I work 12 hour rotating day/night shifts which makes eating on a regular schedule near impossible. Secondly, I LOVE breakfast. :D When I get another job with more consistent hours though I'd like to try the 16:8 method. I'm glad it works for you!
  • juggernaut1974
    juggernaut1974 Posts: 6,212 Member
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    GabrielleCote wrote: »
    ceoverturf, so what you're saying is a deficit makes it hard to build muscle (which I know) but individual daily deficits don't make any more of a difference than overall deficits? Because that is my main concern.

    Not 'hard' - but (generally speaking) impossible.

    What is an 'overall deficit', other than a culmination of 'individual daily deficits'?
  • GabrielleCote
    GabrielleCote Posts: 10 Member
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    What is an 'overall deficit', other than a culmination of 'individual daily deficits'?

    I might have worded that wrong... I am worried that a HUGE caloric deficit on two days a week could mean more muscle loss than a moderate caloric deficit all week.
  • Sarasmaintaining
    Sarasmaintaining Posts: 1,027 Member
    edited June 2015
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    I did alternate day IF for my active weight loss phase, I did 5:2IF for the transition period between weight loss and maintenance (still lost at a slower rate during this time), and now I do 16:8IF for maintenance.
    I <3 IF. My mom is currently doing 5:2IF for her weight loss phase and she's doing really well with it so far.
  • GabrielleCote
    GabrielleCote Posts: 10 Member
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    That's awesome Sarasmaintaining! I'm glad you've had success with IF. With alternate day fasting, on your feeding days did you eat whatever you want? That concept is alien to me - eat whatever you want half the time and still lose weight? I'm a binge eater so I know I would erase the deficit eeeeeasily with cookies, ice cream, candy... Also I've read that way of fasting will decrease appetite, did you find that it did?
  • SMCLosesIt
    SMCLosesIt Posts: 45 Member
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    Fasting is not just about losing weight either, it has many health benefits besides that.
  • missiontofitness
    missiontofitness Posts: 4,074 Member
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    I've never done it, because I know it wouldn't work for me. The idea of eating maintenance? Awesome. The idea of eating a fraction of maintenance calories twice a week? Not awesome. It's worked for plenty of people on here, and it's something they can stick with. It all comes down to what works for you. You can try it, and if you don't like it after a month, there's plenty of other eating plans to experiment with until you find something that works for you.
  • shabaity
    shabaity Posts: 792 Member
    edited June 2015
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    I use 16:8 because my blood sugar has never been stable enough for full on fast days,this was proven several times in high school. But it works well for me. Plus my exercise and work scheduling would make alt day or 5:2 difficult.
  • missiontofitness
    missiontofitness Posts: 4,074 Member
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    shabaity wrote: »
    I use 16:8 because my blood sugar has never been stable enough for full on fast days,this was proven several times in high school. But it works well for me. Plus my exercise and work scheduling would make alt day or 5:2 difficult.

    Brings up another good point; meet with a doctor before trying anything like this.
    I have a heart condition that gets very grumpy with me if I've gone too long between meals, or haven't had enough calories yet in my day. I would only be able to eat around 400-500 calories a day (what usually constitutes part of or an entire meal for me), and I would be having palpitations up the wazoo. Definitely best to get a clean bill of health beforehand.
  • GabrielleCote
    GabrielleCote Posts: 10 Member
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    SMCLosesIt, yes I have heard fasting has some other benefits. I'm not 100% sold on them though... have they been scientifically tested? Is there a place where I can read some studies about them?

    missiontofitness, honestly I don't mind the daily deficit idea, but I am curious as to if the 5:2 eating plan will work better for me. My last physical I was healthy as a horse so I'm going to go off of that. But I mean, if I am consistently miserable 2/7 days a week I will definitely go back to the daily deficit. As a personal challenge, I did 24 hours of fasting on Sunday this past weekend. I read up that it is a type of IF and gave it a shot! It wasn't difficult at all which is especially surprising for someone who (feels) as if they have to eat every 4 hours.

    shabaity, I agree that regular exercise and an irregular work schedule make fasting difficult. My work schedule is a 4 week day/night 12 hour rotation so I had to carefully choose days that I don't lift that I also work (because it's distracting). Over four weeks, I chose 2 cardio days though so we'll see how that pans out!
  • angela233Z
    angela233Z Posts: 312 Member
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    I would suggest you try it for 2 weeks. I was pleasantly surprised that the fast days are easier than I thought they would be. And as you get more recipes, used to it, it actually gets easier with time
  • wanttobefit300
    wanttobefit300 Posts: 157 Member
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    I am on a 5:2 plan. I eat 600-650 cal (45% carb, 25% protein, 30% fat) on 2 days and 1500 cal (50% carb, 25% protein, 25% fat) the other five days. Every day I am supposed to eat 4 servings of non-starchy vegetables, 2 servings of fruit and 2 servings of dairy. The fat, starchy vegetables/grains, and protein servings vary between fasting and nonfasting days. I've lost 11 lbs, 1-1/2 inches off my belly and dropped my A1c from 6.7 to 5.9 in 2 months. The fasting days require careful planning but have not really been a problem. I spread out my food so I never get very hungry. Guys would probably have to eat more on the nonfasting days.
  • honkytonks85
    honkytonks85 Posts: 669 Member
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    I like it because I like to go out and have a calorie dense meal every now and then, IF gives me that flexibility to have two days where I am creating a deficit and not stressing so much on the other days.

    You have to be VERY careful not to overeat on your non fast days to the point where you are cancelling out your deficit. If you find yourself overeating and you think the fasting is to blame, give it a miss and try something else, it's not for everyone.

    I have been doing IF a few years now.

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