The FastDay Forum

Hi all -

I'm new to the 5:2 program, on my second week.

First the vitals: 44 yo male, 6'0". Weight 2 weeks ago was 155-156, week today was 154.

The background: I exercise regularly. During the summer I bike a lot - both road and mountain. I try to get out at least 4 times per week, sometimes if schedule allows I go 6-7 days per week. At minimum they are 90 minute to 2 hours rides 25 to 40 mile road rides, 10-20 mile mountain bike rides. Weekends I'll go for several hours. Starting soon, I'll be mountain bike racing 1 night a week, and doing 50 mile + rides on weekends. About 1 out of 3 weekends will be road rides between 75 - 100 miles, and a few 50+ mile mountain bike races.

The issue: This past Sunday I did a 100 mile ride. I fueled reasonably well during the ride, and very well (burger and fries) afterwards. Monday was a fast day, about 600 calories. It was difficult, to the point where I could not concentrate at work. Mental processes were very clouded.

The problem: I'm not sure how I can incorporate fast days into this schedule. On rides longer than 60 minutes, I have to fuel, otherwise my performance fades and I "hit the wall". I also do a recovery regimen of a 3:1 carb:protein after strenuous exercise, which I have found helps me a lot with muscle recovery. So fasting on days of long rides is really out of the question. But fasting on days after long rides also seems very difficult, and runs counter to research I've seen about how to recover after strenuous exercise.

The question: Is there any advice on how I can work the 5:2 fast diet into a strenuous exercise program, where I really don't want to sacrifice my training and racing performance?

Hi steyermark and welcome!

Not sure I can answer your more technical questions, but wanted to say Hi anyway.

Lots of people do find that they are able to exercise up to their normal levels on fast days and feed days. You may find that you need to let your body get used to fasting first.

Hopefully someone will be along soon who can explain more fully.

Hi steyermark, really glad you brought this up. My daughter (25 yrs.old) was starting out with 5:2 and found that she really ran out of gas during a looong night of dancing with her salsa team. She had trouble concentrating not fainting.

She's trying to figure how to fit things in, as you, since she also runs with her boyfriend several while supporting him in his triathlon preparations.

I guess it's just gonna take trial and error to figure it out. If anyone has any ideas, we would welcome them.

steyermark, I think you're going to struggle on that amount of exercise. If you're only 154 and 6ft, I'm guessing that you're not really looking to lose weight on 5:2 but try for the other benefits?

I cycle for an hour or so 6 days a week (not high intensity) and go to the gym 3-4 times a week for 1-2 hours. I can manage that without hitting a wall even on a fast day but I do get tired. If you reckon you need to fuel after 60 minutes, then fasting might help you draw that out as your body gets better at using other sources of fuel but it doesn't sound like you have many fat reserves!

I'd also question whether you need to do such a lot 6-7 days a week. Your body needs to rest and you need some recovery days in there where you rest or just go for a very short easy ride. If you look at a marathon training schedule (not that much different in terms of what you are demanding from your body on your 100 mile weekends), they would have more slow days.

Honestly, you don't need to do 5:2 for weight (the additional cycling will likely take any more you want to lose off) and it just might not be right for you.

One other thing though to remember before you give up entirely. Your fast amount should be 25% of your TDEE. With that level of exercise, it's going to be more than 600 calories.
Using this TDEE calculator that lets you put in exercise more readily
http://www.health-calc.com/diet/energy- ... e-advanced
and your stats from the first post, I got your TDEE coming out at 3500 (or possibly more) which would be a fast day limit of 875.

Hey, steyermark. I have a strenuous swimming schedule and put in an equal amount of time as you with exercise. So far, I have been able to maintain my workouts on fast days...but the weight is dropping and at some point I will need to change up things. I probably am not pushing to your intensity either...my guess is to increase calories on fast day as well as other days if you're dropping weight.

If you're going for benefits of fasting other than weight loss, maybe consider doing a 3 or 4 day fast every 3 or 4 months? That way, you can take a few days off your cycling schedule too, and just give your body a total rest. You'd get all the benefits of fasting plus a good body rest, ready to come back even stronger.

I can certainly see why it would be difficult...what an athlete- wish I could get that many days of strenous exercise in a week. Kudos on being so active.

I would have to agree with Applesider, considering that you don't need to lose weight I would consider looking at possibly increasing your cals on the two days. I would recommend perhaps following a 24hr fasting period dependent on your exercise schedule 3pm-3pm and eating a reduced yet reasonble intake. For instance post exercise snack and normal dinner or lunch.

Brad philon, advocates such an eating schedule which Dr. Mosley has cited and some 52ers also follow. Another regime you can look at is possibly the 16:8 regime ( fast 16hrs with an 8hr eating window). Overall the health benefit in many of the various IF protocols are dependent on the length of ones fasted state more so then calorie intake.

Hopefully you find a routine that works for you. I suggest u play aound w/ both esp the 16:8 as it allows for more flexibilty as you modify it to suit ur needs w/o necessarily reducing ur cal intake drastically.

Good luck!

You might try to see if you can work in 6:1 first, see how that strikes you. It gives a lot more flexibility to your week than 5:2 would.

Maybe if you plan your workouts such that you're not hitting it too hard on fast days and take a day off exercise the day after fast, or if that doesn't work you take it easier on the day before a fast day and then take the fasting day off of exercise. Feel it out.

Training as much as you do I'm sure you get tons of advice on how to avoid overtraining, so I won't lecture you on that.

Since you are exercising so much and it doesn't appear like you need to lose any weight, make sure you eat more on your feed days to make up for your fast days. You don't want to create a caloric deficit over the course of a week if you don't want to lose weight. Sounds like the day before your fast days might be a good time to put down a couple hundred extra calories than you otherwise might.

Not sure what your motivation for 5:2ing is but my view is it aint worth you doing both unless you`re hell bent on trying to bring your weight even lower. You`re basically getting all the `health benefits` already with the cycling, apart from the maybe contentious one of lowering your igf-1.
If you are serious about 5:2ing I would reduce the cycling to maybe your mid week mtn bike race and one long ride at the weekend. After doing a 100 miler I would make sure I rest properly , 2 days off the bike and wouldn`t fast in that time. Refilling the glycogen stores and rest would be my priority.
The bloke who writes this blog takes reducing his carbs (sugar intake) very seriously and is in to cycling, plus he`s a medical Dr. His blog is interesting and very technical at times. If your intention is to get your body to a state where you are heavily dependent on fat burning for exercise and are religous about reducing carb intake then he reckons it`ll take you 10-12 weeks to adapt to a state where you are comfortable doing endurance exercise on low carb. I reckon it`d be an arduos and painful journey to get there... Ideally it sounds like physiologically that`s how all endurance athletes should be but living in the western world in 2013 make it a v difficult goal.
Website is http://eatingacademy.com/

Good luck to you.
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I would endorse skippyscuffleton's advice to check out Peter Attia's website, it is fascinating. He fuels with fat and can stand 6 - 7 hour hard rides at a good pace without carbs - the only downside is that ultimate peak performance is slightly reduced so gold medals would be out of reach.
You will be a beacon for the rest of us if you manage to sort out a way to blend 5:2 with such a high workload - good luck, and keep us informed as you experiment!

My sons friend is a sport scientist. He does the 16:8 without reducing calories at all so that he gets he benefit of the fast but doesn't lose weight. He keeps up a pretty punishing exercise routine. I would definitely check out what Brad Pilon says.

What a great community! Thank you for the very helpful responses.

Correct, I'm not trying the 5:2 for weight loss. The main benefits I'm looking for are a lower % body fat, a better cholesterol profile (while I eat reasonably well and am active, my cholesterol is high), and a better insulin response, which I figure certainly can't hurt.

A major side benefit I'm looking for, as some have mentioned, is better use of fat as a fuel during endurance events, rather than relying on carbs - endogenous or exogenous.

The 6:1 would certainly work very well for my lifestyle. That seems much more doable. I'm going to wait a couple of weeks and see what happens with weight and training, and then might move to the 6:1.

Another question for you all - I've read that some folks do the 5:2 with only 2 meals on fast days (breakfast and dinner) with nothing in between except non-caloric fluids, while other spread the alloted calories out and have some snacks, such as berries, throughout the day. What are the thoughts on this? Does snacking result in the same health benefits as a stricter 2 meal-only day?

Thanks again for all the great advice and feedback!

A lot of us do 5:2 with just one meal on the fast day (dinner). Why? Personally, because if I have breakfast or a snack, it wakes up my appetite and I end up fighting hunger a couple of hours later. If I ignore the odd hunger pang and grab a coffee then, I can easily wait til evening - even if I end up going to the gym and not eating til 8.30 or 9.

I find that nothing until dinner helps control hunger better, and usually eat all 600 cal at dinner or 500 at dinner and the last 100 as a snack midway between dinner and bed.

There are some things out there that the longer you go not eating anything may increase the benefits of fasting, so saving your 600 cal to the end of the day, if you can do it, may work to increase the health benefits you are after.

breadandwine says something about a "hunger switch" that rings true, that you may be hungry, but you don't know how hungry you are until you eat a little something. That's why not eating throughout the day works for me. If I eat a small snack at noon or start out in the morning with 50-100 cal I have more troubles with hunger than if I don't eat until evening.