The FastDay Forum

Hi everyone.
I've got a massively busy two weeks coming up which is going to include a LOT of eating out so I'm thinking of doing a couple of b2b fasts so I can still do 4/3 and minimise any damage
Here's my plan. Any advice welcome, I've never done b2b before.

Sat 8th - meal and drinks out with friends
Sun - FAST (or 16/8?)
Mon - FAST
Tues - Daughter's birthday Italian meal out
Weds - FAST
Thurs - OH's 40th birthday - big fat curry out
Fri - FAST
Sat - normal
Sun - FAST
Mon - FAST
Tues - away in hotel breakfast and dinner included
Weds - same
Thurs - same
Fri - same
Sat - coming home (maybe 16/8 possibly)
Sun - FAST
Mon - FAST

I haven't done many back to back fasts. The first was really hard, the second easier. I've done a few since that just happened as I wasn't particularly hungry the next day. Your schedule looks quite difficult to me, as you have a period of nine days where you would only be eating normally on three.
Personally I wouldn't do your schedule, it would be too tough for me, but I'd maybe do eating windows where possible. If this run of events is exceptional, I'd probably accept it as that, try to eat reasonably, but think of it as a bit like going on holiday!
Whatever you decide to do, it looks like you will have a busy, but fun two weeks! Enjoy it!

[Debs]

People do it, but we don't recommend more than 36 hour fasts on this site. Personally I have done it, and it wasn't too bad. Maybe a better idea might be to go to 19:5 or 16:8 as per the eating window threads; you would still be eating something but still less than your TDEE?

I'm not a fan of back to back myself, but I think some people here regularly do it.

Hi! I agree with Annurca, though it might be useful to have @carorees thoughts on your plan. Try to be guided by how you feel each day re what is doable - and with the hotel breakfasts and dinners, go for the lower carb options if you can, perhaps rather than 2 fasts immediately before you go away? But the main thing is to enjoy yourself! Best wishes.

This is a great way to get your metabolism to slow way down. I wouldn't recommend it.

I tried doing extra fasts before a week of major eating and am having a really tough time now with weight loss completely stopped. This is even though I didn't miss any fasts and have been fasting on my regular schedule for two weeks after.

Those back to back fasts might push your brain into deciding you need to conserve body fat because starvation is threatening.

[carorees]

I'm interested that @peebles suggests that back to back fasts would affect metabolic rate. I'm not so sure. The following papers suggest that metabolic rate goes up with fasting at first and does not drop for at least 72 hours:
http://www.ncbi.nlm.nih.gov/pubmed/8172872
http://www.ncbi.nlm.nih.gov/pubmed/10837292

The Two-Day Diet which is the intermittent fasting diet that was created by the researchers at the Manchester Christie Hospital, and which is the only 2-days a week IF protocol that has any published papers to date (Harvie et al.) use two days of back to back very low carb fasting days.

In summary, if back to back fasts suit you, just go ahead and do it.

@Carorees,

Those studies are done in non-weight reduced, fasting-naive subjects. Therefore the effects they find are very unlikely to apply to overweight people who have been doing IF for an extended period of time and who are, in addition weight-reduced.

I base this on what I've read in the many similar very short duration low carb diet studies that were performed on subjects that only ate the diet for a few days or weeks. The findings of those studies were often the opposite of what was found when studies were run of dieters who stuck to the diet for six months or more--long enough to adapt to it. This was true both for positive findings like improvements in leptin which disappeared and then went negative after habituation and bad side effects like temporarily raised cholesterol and decreased mood which reversed after habituation.

Plus, we've discussed in previous message threads the way that counter-intuitively people often find their weight gain improves when they fast less intensively. Adding that extra fast doesn't ramp up weight loss in a straight line way at all. In fact, it seems, anecdotally that it may slow it. So I take this as a hint that our brains don't take well to too much deprivation and interpret it as a sign we are going into a period when food will be increasingly scarce and slows the metabolism to keep us alive. Two days running is much more physiological stress than alternate days when there is glycogen refilling and other signaling to tell the brain that there is food available.

So why flirt with fasting so much that your body kicks in with a starvation response?

[carorees]

@Carorees,

Those studies are done in non-weight reduced, fasting-naive subjects. Therefore the effects they find are very unlikely to apply to overweight people who have been doing IF for an extended period of time and who are, in addition weight-reduced.

I base this on what I've read in the many similar very short duration low carb diet studies that were performed on subjects that only ate the diet for a few days or weeks. The findings of those studies were often the opposite of what was found when studies were run of dieters who stuck to the diet for six months or more--long enough to adapt to it. This was true both for positive findings like improvements in leptin which disappeared and then went negative after habituation and bad side effects like temporarily raised cholesterol and decreased mood which reversed after habituation.

Plus, we've discussed in previous message threads the way that counter-intuitively people often find their weight gain improves when they fast less intensively. Adding that extra fast doesn't ramp up weight loss in a straight line way at all. In fact, it seems, anecdotally that it may slow it. So I take this as a hint that our brains don't take well to too much deprivation and interpret it as a sign we are going into a period when food will be increasingly scarce and slows the metabolism to keep us alive. Two days running is much more physiological stress than alternate days when there is glycogen refilling and other signaling to tell the brain that there is food available.

So why flirt with fasting so much that your body kicks in with a starvation response?

Very good points @peebles, but my understanding from the OP was that it is just on two occasions that she was thinking of doing b2b fasts?

@carorees and @peebles - it's an interesting discussion and I wonder if, to some extent, the general applicability of this is separate to the specific context of the OP.

My personal opinion, based on anecdotal impression of watching people implement B2B in a similar fashion, is that I've never seen it have the desired outcome.* By and large, it's one thing to have B2B fasts, followed by a 3-7 day run of non-fast days, but when people start having B2B with only 1-2 non-FD in-between, there seems to be a heightened risk of having what is known as an Up, Up and Away Day (aka, significant over-eating). I've no idea why this didn't show up in the trials and can only think that the people who ran the trial recruitment were very competent at screening out participants who would have been vulnerable to over-eating in a similar fashion and that the participants followed the trial protocol (i.e., not what the OP is proposing).

I wonder if you'd need to be a faster with no history of experiencing feelings of deprivation or restriction in order for B2B with few non-fast days in-between to work? (As above, the Genesis 2 Day Trial had 5 days in-between and may well have set people up for the fasts differently.) Particularly as the OP's context of those non-fast days is that they are celebrations/festivities.

My tuppence? Keep to your regular schedule.

*I've deleted what feels like an essay on this topic. The bald summary is that it seems almost impossible to discuss this without dragging in the context of eating disorders which is inappropriate here.

Thanks so much for the replies
I'm thinking it might be a bit heavy going as I originally planned it so I'm going to modify slightly;

Sat 8th - meal and drinks out with friends
Sun - FAST (or 16/8?) THIS IS NOW A NORMAL EATING DAY AS I HAVE A RAGING HANGOVER
Mon - FAST
Tues - Daughter's birthday Italian meal out
Weds - FAST
Thurs - OH's 40th birthday - big fat curry out
Fri - FAST
Sat - normal
Sun - FAST - CHANGE TO NORMAL DAY AS I'LL HAVE DONE 4:3 THE PREVIOUS WEEK ANYWAY
Mon - FAST
Tues - away in hotel breakfast and dinner included
Weds - same
Thurs - same
Fri - same
Sat - coming home (maybe 16/8 possibly)
Sun - FAST
Mon - FAST - CHANGE TO NORMAL AND GET BACK INTO A ROUTINE.
This is all really because I'm starting to make some progress on my Christmas challenge and I didn't want a few days away to set me back but I'm going to make sensible food choices and enjoy myself without adding too many extra fasts if I can help it. Thanks again everyone xxxxx

Back to back is really hard, you might manage the first back to back but two or three in a row? Well I never managed it.
However what an achievement and 5 days of eating ahead of you.
Never the less reserved for emergencies in my case

So I'm halfway through my crazy two weeks. I am run down and exhausted and mad busy so I haven't exercised at all. Because I've been poorly I haven't drank as much booze as I would have usually done on nights out and I've not eaten too badly all things considered.
I hit a new low again on the scales on Thursday so I was absolutely delighted but on weighing today (after one normal and one fast day) I seem to have gained a couple of pounds but I think/hope that's just a blip.
Tonight though I just can't seem to control my eating. I've had half a bottle of red wine, loads of crisps and nuts, some sweets etc on top of a calorific dinner, I don't know what's wrong with me, proper munchies!! I genuinely have not felt deprived at all this week, I've not struggled with my fasts (although yesterday's fast was carb heavy - poor snacking) and I've enjoyed my eating out whilst not going OTT. Arrrggghhhhh self-sabotage rears it's ugly head yet again

I have lots of sympathy @JennyH10! I have days just like that... Most frustrating when you were really trying for a couple of weeks of controlled eating. Others will be able to give you some physiological explanations for what is going on beyond self-sabotage. But at this stage, just accept that this is what you have done today, and that tomorrow is another day and you can go back to your plan. Good luck and best wishes!

Some reflections on my own experience:
I have always done 5:2 in a back to back version, fasting two days, but really making sure I was eating regularly on the 5 days after them. Done this in a relaxed way (no trouble in two days fasting, but spreading eating over those two days (small breakfast, lunch and dinner)). Have no longer than 3 months experience, as I reached goal after that (from BMI 25 to 21). Always liked to have 5 non-fast days to look forward to. So, in my personal context, it was ok, to do it. No trouble with starvation mode or changing metabolism, as the 5 normal days would take care of that. In my perception, making sure you eat regularly on the non fast days is just as important as eating less on the fast days. No point in rushing.