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fasting one day a week?

I have had some success in the past with the 5-2 diet (where you eat only 500 calories two days a week) and I was going to give it another go but then I thought that it might be easier to have one day where I just cut out food altogether (allowing myself unlimited coffee, tea and water). I figured this would mean I would have the same overall deficit for the week but I’d only have to do it for one day instead of two. Is this a completely awful idea or has anyone else tried this and had success?
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Replies

  • CarvedTones
    CarvedTones Posts: 2,340 Member
    edited October 2018
    I also considered back when I did 5:2. If you are considering it because the 2 VLC days are hard to endure, then it is likely a bad idea. If they aren't hard to do, it would certainly work and one day a week isn't unhealthy (some studies say the opposite). I couldn't do it regularly. I put off most of my calories until dinner on the VLC days to make it easier to go to bed without feeling starved and just the day was tough. I couldn't handle 5:2 for very long and I was also abusing it and eating at a deficit on other days and ending up with an unhealthy overall deficit.

    But in the end, the math is all that matters as long as you aren't doing enough days in a row to be unhealthy.
  • sijomial
    sijomial Posts: 19,057 Member
    shw112 wrote: »
    I have had some success in the past with the 5-2 diet (where you eat only 500 calories two days a week) and I was going to give it another go but then I thought that it might be easier to have one day where I just cut out food altogether (allowing myself unlimited coffee, tea and water). I figured this would mean I would have the same overall deficit for the week but I’d only have to do it for one day instead of two. Is this a completely awful idea or has anyone else tried this and had success?

    Don't see how you would have the same weekly deficit unless you are eating a tiny, tiny amount of calories?
    5:2 with a "typical average" female TDEE of 2000 creates a weekly deficit of 3000 cals.
    Eating nothing one day a week just creates a 2000 deficit.

    Having one fasting day a week isn't by itself awful health-wise but it depends what you are doing the other six days of the week.

    (No I didn't try it, I did the regular 5:2 eating pattern to lose weight with 5 days at maintenance and two days restricting to 600 cals which personally I found easier than the usual everyday deficit.)
  • mph323
    mph323 Posts: 3,563 Member
    edited October 2018
    If you find it easier to just not eat as opposed to eating just a little, then fasting one day might work for you in in the context of weekly calories. However, without knowing your current weight and target weight, I would be concerned that at 1200 calories daily plus one fast day you are not eating enough to fuel your sedentary activity, let alone any exercise on top of that.

    edited because maths - Make that you are undereating at that rate period, since your daily calories would be under 1200. Not smart.
  • ahoy_m8
    ahoy_m8 Posts: 2,531 Member
    I did do something similar for several months. Mondays were my "low day" at ~750kcal. I also saved calories for a "high day" on Sunday. I had no problem getting through Monday, but I did feel peckish and low energy on Tuesdays. The biggest difference between what I did and what you're contemplating is I was only shooting for 0.5lb/week loss, so my deficit wasn't nearly as steep as yours the other days. I agree with the comments that your plan sounds like a crash diet.

    I appreciated the caloric variety at the time, but ultimately, I found I do better with a more even intake. On the whole, less binge risk. 2lb/week loss is hard no matter how you arrange the calories. It's really only appropriate for folks with a lot to lose. How much do you have to lose, OP? You will save yourself time, effort and anguish in the long run by picking an appropriate rate of loss/calorie goal in the first place.
  • psychod787
    psychod787 Posts: 4,066 Member
    Look up lyle McDonald, he talks about it some.
  • kimny72
    kimny72 Posts: 16,000 Member
    shw112 wrote: »
    sorry my maths was a little off. I am hoping for at least 2 pounds a week, and would still only be eating around 1200 calories on the other days, but fasting one day a week would obviously speed up the process and allow for some leeway if I ended up going over on any of the other days

    I don't have any feedback on the fasting plan, as I've never attempted to not eat for that long. But it is not healthy to aim to lose more than 2 lbs per week, unless you are very obese. Even 2 lbs per week is very aggressive.

    Set a realistic and healthy goal, then you can look at your calories weekly rather than daily. If you can fast for a full day and not experience energy or appetite problems that lead you to over-eat in response, I don't see anything wrong with it. If you have any blood glucose issues, or any medical conditions really, I would check with my doctor before fasting for a full day.
  • shw112
    shw112 Posts: 60 Member
    As background my start weight was 204 pounds, current is 165 and my goal is 140 (I'm 5 ft 10).

    I am aware that fasting one day a week and only eating 1200 a day does sound aggressive, but since I absolutely suck at sticking to the 1200 limit i almost inevitably end up going over it by quite a significant number of calories at least one day a week, so I think that a one day fast would probably compensate for that. Also a fast day would probably not actually be 0 kcal, seeing as i will be having coffee with a splash of milk (i absolutely cannot drink my coffee black despite my best efforts) and sugar free fruit squash which is about 10kcal a glass.
  • arobey11
    arobey11 Posts: 86 Member
    shw112 wrote: »
    As background my start weight was 204 pounds, current is 165 and my goal is 140 (I'm 5 ft 10).

    I am aware that fasting one day a week and only eating 1200 a day does sound aggressive, but since I absolutely suck at sticking to the 1200 limit i almost inevitably end up going over it by quite a significant number of calories at least one day a week, so I think that a one day fast would probably compensate for that. Also a fast day would probably not actually be 0 kcal, seeing as i will be having coffee with a splash of milk (i absolutely cannot drink my coffee black despite my best efforts) and sugar free fruit squash which is about 10kcal a glass.

    If you know you're going to go over, why not raise your calories, eat them consistently, and plan to lose 1 lb/week? I'd just worry that you'd be setting yourself up for failure and inaccuracy and then how will this translate to maintenance when you're done losing? Do you plan on overeating during the week (over your maintenance cals) and then not eating for a day for the rest of your life? Once you lose, your calorie needs will be lower to maintain your weight, so fasting for a day could potentially only save you ~0.5/lb of weight gain, which depending on your habits may not be enough.