If you've followed along, I have been working on transitioning to a low carb, high fat diet for nearly 2 months now. It was a struggle to adapt at first. I tried to go into nutritional ketosis by limiting my carbs to 50g per day and I just couldn't do it. All of my runs felt terrible and I just had a hard time finding a "happy place" where I had some flexibility with my diet. Ketosis requires zero tolerance for cheating and I just enjoy some things too much to live with zero tolerance.
I have settled on what I would term a "high fat version of the Paleo diet". At this point, I think the Paleo diet is becoming an overused term and has slightly different meanings to all that follow it. For me, it basically means real food: nothing processed or out of a box, no fast food, organic and grass-fed if possible/reasonable, minimal sugar, and no grains of any kind. However, while Paleo eaters eat more fat than most Americans, there is nothing explicit that says it has to be high fat. You could eat meat and vegetables all day, in which case you'd be eating primarily protein and carbs, particularly if you picked lean meat (often prescribed by Paleo followers). What I have done is to go out of my way to eat fat when possible -- fatty cuts of meat, whole fat cheese, whole fat milk, full fat greek yogurt (careful with yogurt, lots of sugar), heavy whipping cream, coconut oil, ghee, almonds, avocados, olive oil, eggs, and bacon are my staples. However, I still eat some carbs in the form of berries, organic apple sauce, beer or wine, vegetables (no limits on Paleo friendly veggies), and a periodic cheat item like a Bing energy drink.
The only real difference between now and 2 months ago is the amount of fat I eat. The benefits of this change are that I am finally eating close to 3500 kcals per day -- which I need to run 55 miles per week at 190 lbs -- without feeling like crap or gaining weight. I haven't had an episode of the "runner's trots" in months. My overall gut health has improved tremendously. One example of a dish that I really enjoy pre or post run is a high fat Paleo hash my wife has been making. The base is sweet potatoes, kale, and onions that are sauteed in oil. Then it is mixed with cooked 80% lean ground beef (don't drain off the fat) and topped with two eggs. Yum!
On the run, I have started to allow moderate amounts of carbs to keep my energy levels up. For now, I am really enjoying Skratch Labs as a low calorie (but mostly sugar) beverage. I have found that just a minimal amount of carbs coming in keeps my brain from feeling fatigue. For example, I tried to go without any carbs on my Saturday run and my mental perception of the difficulty of the run increased dramatically. Sunday all I had was a few swigs of Skratch (maybe 100 calories) and I felt strong the whole run, despite it being day 2 of a back-to-back and having fatigued legs. I will also enjoy Hammer Bars on the run. Again, they are primarily carbs, but they pass the "real food" test being entirely organic and non-GMO ingredients. Once in a while I use Generation Ucan pre-run, but I don't know that I am sold on that product. It is expensive, difficult to work with, and somewhat limiting because it is ineffective when mixed with high sugar products. I think it works, I just don't know that it works for me. I fully expect that I will take some gels in longer races, particularly in later stages.