Lack of carbs might be a problem for running. Most of the long-term runners ate lots of carbs in the past, it was a "tradition" back in the running boom days of the late 1970's thru early 80's. I used to carb load for races of a half marthon upwards. I now stay in ketosis at least 5 days a week and do "refeed" days the other 2 days. This is not so much for weight loss, as it is to avoid insulin spikes and BS spikes. When I eat carbs I take insulin mimics to load the carbs in muscle cells and the liver to rebuild glycogen supplies for the week. This doesn't slow dieting efforts down much at all.

I have a chronic problem on my left ankle that keeps me from running, but the constant ketosis this last few months (or weight loss or something) has made it better, maybe... just perhaps....

Anyway as I've mentioned before I still do much cardio/arerobics these days, and a lot of resistance training too. My energy levels remain high most of the time while working out, even during severe calorie restiction, and even 3-4 days out from my refeed days.

I use a supplement stack. This stack hasn't any stimulants in it, in fact, it's healthy. It's composed of three supplements combined:

Beta alanine
Citrulline malate (2:1 is best)
and Cordyceps

The most important one is the cordyceps -- this is the stuff the sherpas use to climb Everest without oxygen, but it's hard to find decent cordyceps with most of it ranging for mediocre to outright useless. Beta alanine is the best stuff for getting rid of lactic acid in your body. Citrulline malate ups ATP in your sytem and relaxes arteries letting greater blood flow through and improving heart health as a bonus. In combination they act synergistically to give you deep down energy reserves when you call on your body to perform, but you barely notice their effects until you need them -- no stim effect. Short of drugs like EPO this is great stuff.