fuel for long distance running

I am training for a 24km race in December. I have to do a long run once every 2 weeks and usually take in fuel which is mainly glucose and electrolytes for any run over 1.5 hrs long. This obviously doesn’t fit in with the no sugar rule. I am just starting out on following the weight loss program and don’t really know what to do about this. I will be running for between 2-3.5 hour long training runs.

I am not running for weight loss, but for mental well being and getting over the “I’m not good enough” hurdle and have been doing this since January this year with a coach. Not completing this goal is not an option for me. I would appreciate some advice if you can.