The FastDay Forum

I jumped back on the wagon on Friday and have been within my cal allowance for my height.
We are doing walks and i ate some of my exercise cals Sunday (I'd earned 1117cals and ate 400 of them) but I failed at my fast today because I was hungry! We walked 6.7 miles and I'd done 9 mins on cross trainer this morning. We finished our 2hr35min walk at 3.30 and ate 700ish calories at 6pm. It was 21 hours since my last food, so does that count as a fast? I won't get to eat until dinner time tomorrow either! I just don't know how to work fasting around exercise! I'd just had surgery last time I did 5:2 so I wasn't exercising?

hi @Karenm - great exercising, good for you!!

I think it's generally said on the forum that it's best not to increase your calories on fast days even if you're exercising. I think this is because it's possible for some people to over-estimate the calorie cost of exercising, and over-compensate (and I reckon even the electronic calculators get it wrong, because our bodies are such efficient machines). But if you need to eat, I'd try to avoid carbs if you can, and maybe just eat something like almonds. That way the fat-burning continues.

I guess it ultimately depends on how fat-adapted your muscles are (see marks daily apple and Peter Attia's blog - I'll try to look up a link later on). When I first started exercising on fast days, riding say 40 km on my bike, I used to really hit the wall, come back home & gorge on carbs and wonder why my blood sugar went up to 10! These days it seems I can do any amount of exercise and not have to eat to compensate. But it takes a while, maybe six weeks or so, of fasting while exercising for your muscles to develop enough lipoprotein lipase to be able to burn fat over carb somewhat more selectively (you'll still burn some carb, especially at high intensities).

Good luck, and happy walking!

Cool. I will bear that in mind. I've only done an occasional fast in the last 7 months and Friday was my first exercise! I think I should have built up the exercise more slowly, but I'm determined to shift this weight again! I realise the endomondo app is inaccurate which is why I ate 400 of the 1100 it reckoned I'd earned! I just need to get back in my stride as I know I can do this.

[carorees]

Machines that tell you how many calories you've burned while exercising don't tell you just the exercise component but the total calories they reckon you've burned during that hour(or however long) but of course you would have burned some calories if you'd stayed sat at your desk! You would probably need to take off at least 100 cals per hour from what the machine says. And avoid the tendency to over compensate with food and avoid the tendency for your body to recoup three losses by making you move less after doing the exercise (which is what it does).

....avoid the tendency for your body to recoup three losses by making you move less after doing the exercise (which is what it does).[/quote]

Honestly! The body is sooo sneaky isnt it! meh!

[carorees]

Here's some info I wrote about exercising and fasting: https://www.fastday.com/fasting/can-i-exercise-when-intermittent-fasting/ and about how exercising affects metabolism: https://www.fastday.com/fasting/how-does-exercise-affect-metabolism/

[Tracieknits]

Well the formula for 5:2 is (for women) 500 calories or 25% of your total daily energy expenditure, whichever is higher. So if exercising brings your calorie estimate to 2400 calories burned in a day, I say by all means eat 600 calories. If your exercise brings you to 2600 calories burned, eat 650. Ish. I never worry within 10% or so either way.

Did I understand correctly that you fast all day Monday, consume your calories in the evening, and then fast again until dinner Tuesday night? You may be making it unnecessarily hard on yourself. While it's not forbidden to do, I am in the "make it sustainable" camp!

The best diet for anyone is the one they can stick to long-term. Hubby and I have been eating this way for over a year -- I have never stuck with a diet longer than six or eight weeks before!!! So even if I'm not the fastest loser (in part due to thyroid troubles last year), I've been losing consistently and I feel I've struck a nice balance between weight loss and sustainability. I can really see myself sticking with this for the rest of my life!!

So don't feel the need to make the diet/way of eating harder than it needs to be. I know that for the first few moths at least, I was very, very, very ready for breakfast the day after a fast day!!

Did I understand correctly that you fast all day Monday, consume your calories in the evening, and then fast again until dinner Tuesday night? You may be making it unnecessarily hard on yourself. While it's not forbidden to do, I am in the "make it sustainable"
!

I don't tend to feel hungry straight after fasting. I was really hungry on Monday, but haven't been hungry today (I've kept myself really busy sorting out the camper) last time we did 5:2 we tended to fast during the day most days. I am struggling with getting my head around stuff and am finding I'm sticking to 1200 on non fast days!

[Tracieknits]

Whoa, you're doing 1200 calories on regular days and 500 on fast days? And exercising?

That sounds like a fabulous way to completely mess up your metabolism! Unless you're short, I'm pretty sure that's not enough calories.

You know you're supposed to eat to your TDEE (Total Daily Energy Expenditure) on non-fast days. Have you calculated that to know what it is?

I'd forgotten about TDEE until stupid o'clock this morning. I'm not tall so it's 1735 and fasting cals of 434.
I've fasted today and had 465 calories. Out in the camper tomorrow........fish and chips for tea
I will get my head back around this wol soon

[Tracieknits]

Well you might find it's easier and more sustainable if you have a few days with more calories.

Some people shave a few calories off of most feed days and then have a big splurge day one day a week too. It can help with metabolism and with sustainability

When you said you earned 1117 calories, was that in one day?? That seems very high, if it was!

When you said you earned 1117 calories, was that in one day?? That seems very high, if it was!

Yes, I went on cross trainer, then we went kayaking and then 3 hour walk. Endomondo and MFP worked them out at 1117cals! I won't be doing that too often.