Running and intermittent fasting / low carb diet

[LakeFlyPie]

I have been running jogging very slowly 5k a couple of times a week since completing C25K a few months ago. Started Fast 800 last week and have tried a couple of runs both of which have been really difficult. Legs feel like lead and had to keep stopping to walk and felt I just didn't have power / energy. I am fasting until lunch and having an evening meal. Tend to run pre evening meal. After the 1st difficult outing last week I tried having a little Greek yog and blueberries mid afternoon and 2 Brazil nuts 30 mins before going out this evening and if anything it was harder.
Any advice would be gratefully received. I'm keen to keep the running going if possible but weight loss over next 10-12 weeks is my priority.

Could you swap for an early morning run?
Or do a sprint session of 10 min max, alternating 30 seconds of max intensity (a tiger is chasing me), 1 min recovery, 30 sec, 1 min recovery, repeated 6 times, so you run 3 minutes total but health wise and metabolically wise you get more benefit than a slow 5k

I found it very difficult to follow a very low carb diet and still keep my running going. I completed C25k last year and was trying to increase my distance and found it almost impossible on 800 calories. I reduced down to 1000-1200 and still lost weight, but just not as quickly. I do run at 6am so I’m in a fasted state (since 8pm the previous evening) and don’t eat until midday. I do eat after runs of more than an hour though to help with recovery.

For me the priority was to keep running and not lose my fitness. I did find doing some strength training beneficial (so running x4 times per week and strength training x3 times). When gyms were open I did weights, but now I just do strength training classes with dumbbells and resistance bands.

If you are very keen to do fast 800 is to accept the hit on your running and run shorter distances. It is possible to become fat adapted but I believe it’s quite hard to do.

Thanks for the replies.
I'm really missing my regular Body Pump classes at the gym.
C25K has been brilliant for gaining a different kind of fitness.
Will try 1 more 5k tomorrow to see if it was just a couple of bad runs and if it's still a struggle will try shorter, faster bursts.
I dug out my old 20 min Shred DVD the other day and that felt a lot easier than the runs.
I'd like to complete 12 weeks of fast 800 if possible and then probably move to 5:2 so could restart run training when I reintroduce some carbs on non fast days