The FastDay Forum

I started the 5:2 diet five weeks ago and posted that I was really struggling to train the day after a fasting day. In the interim period my weight has dropped by a stone and I have slowly adapted to this lifestyle change and am very pleased with the results that I am seeing.
Over the past few weeks I have noticed a dramatic change in my training and I am now completing progressively more gruelling sessions following my fasting days which I am assuming is because my body has changed and it can now switch much more easily between fuel sources. Obviously my weight drop has helped but I am really pleased with how I have been able to gradually crank up the intensity of my sessions.
I was worried that I was going to have to lose the weight and accept that there would be a resulting drop in fitness and then, when I had hit my target and switched to a 6:1 pattern, increase my training back to where it was. As it happens that is not the case and I am very happy about it. Yet another positive benefit of the diet.

Hi Simon,

that's reassuring to hear. Since starting the 5:2 diet I haven't been able to run at all as I've injured my foot. I'm hoping to get back into training, gradually, from next week, but have been dreading stepping on the treadmill and being right back to square 1. Hopefully I won't have lost my fitness, and may even improve quicker than before!

Hi Simon,
I've just started doing C25K (second week in now) and I love it, I find that I am progressing quickly and feeling great - and I have never been a runner before, always opting for exercise dvds (and then getting bored!). Whenever I have tried to go running the past I have found it hard and no fun but I really enjoy it now, seemingly running + IF go hand in hand!

Any tips Simon - I'm 9weeks to the marathon. Running 40miles a week. The short runs are about 6miles and obaviouly the long are increasing. Justs feel very tired, sluggish and dizzy

I have been doing 5:2 since April of this year and lost about 22 lbs, currently 178 lbs. I run mostly on non fast days but do run some fast days. I do weekly half marathons and noticed my performance has improved from 10 min+ miles to 9 min+ miles, not fast but running with a little more gusto for my age !

Any tips Simon - I'm 9weeks to the marathon. Running 40miles a week. The short runs are about 6miles and obaviouly the long are increasing. Justs feel very tired, sluggish and dizzy

Firstly, you have 9 weeks to go so there is plenty of time for things to improve. Without knowing anything about you or your training schedule it is almost an impossible question to answer. Assuming that you haven't just suddenly increased your mileage then you probably need to look at other issues such as hydration. Maybe you also need to have an easier week to recover a little. How long is your long run?

Being tired and sluggish can happen but I would be more concerned by feeling dizzy. If that continues then I would definitely seek medical advice to make sure that your BP is ok and that you do not have an infection or virus of some kind.

Which marathon are you running?

Hi Simon

Well just to advise - I had a disaster last night. 6miles I should easily run in 60mins but got dizzy spell half way through. I'm sure it was fasting 2 days in a row. I have 13miles to do tonight and am currently eating pasta in anticipation as I still feel kind of sluggish.

Had my BP checked last week as have been a bit concerned with the dizzy spells but the pace should be slower tonight. I think 4:3 is a bit too much when you're running as much as I am. You do need sustenance- I think 5:2 with a day in between to build up is probably a better idea. Was just being stupid in anticipation of holidays in 2 weeks time. I only have 4lbs til I hit a weight I'd be ok with.

I'm doing Dublin city Marathon with about 10others. Did it couple years back but this year its just for fun. I'm supporting a friend who is new to running and very slow but we have the most enjoyable runs as we all support each other. I'll post back tomorrow and let you know if my intake of food helped today. I'll defo hit 1400 cals by tonight which is my TDEE thingy.

Hope everything went well.
Just one thing leaps out immediately. I would be amazed if your 1400 TDEE is not the level for someone who is not exercising whereas you are doing the exact opposite of that. You are possibly massively below what your daily calorie intake should be which in itself would leave you feeling shattered. I would recommend reviewing that as a starting point.

Oh my God Simon, I took a look at the TDEE as recommended. I should be at 1800 not 1400. Don't know where I got the latter from. Just to say my 13.1 went really well last night as made sure I had lots of carbs before. I have a 6mile tonight on a fast day so keeping my food until about 5pm and having coffee and water til then. It's my third fast this week so may not keep it as strict as the other days. Today is definitely easier than Tuesday though so 2 fasts in a row is a silly for me if I'm exercising. That would be my big tip. No dizziness or anything last night