PatW is correct. It is a settled fact that fat will not provide proper fuel for higher intensity efforts, like climbing. You need to use the carbohydrate energy pathway. Most long distance riders fuel off carbs with 15%-25% protein and a little fat, probably less than 10%. Your body should not have an issue with carbs while riding and immediately after riding. Start testing your blood sugar while riding, at least every couple hours. Going too low is bad for you. Carbs with a little protein will help you keep it even, just don't eat too much at any one time. A little every 15 minutes is about right. You might do fine adding just a sports drink, but be sure to also bring plain water so you can feather the effect.
One does run into all sorts of claims on the web. There's a whole subgroup who eat nothing but raw meat and claim incredible athletic feats while doing so. Ignore that stuff.