Hi @jillmcafee

I'm a "lower carb", not low-carb, runner. My longer runs are 20 - 34km (12 - 21 miles); most of my runs are 12 - 18km (7.5 - 11 miles). Basically I try to get in as many 90 minutes or longer runs as often as I can schedule it - sometimes those runs are on difficult mountain trails so the distances are shorter but the training benefit is still there.

Lower carb for me can be anything from 50g carbs (all in, I don't track net carbs, barely track carbs period) to 150g on average for a running day. I base my carb intake on 35% carbs / 25% protein / 40% fats. What I try to do is reach a minimum protein goal; I try not to over do carbs; and I let fats fall wherever.

Most days I run completely fasted but if I don't get out in the morning, then I'm running a couple hours after my last meal typically. Except for super long mountain runs I never eat / consume energy during most runs - it's only when going beyond 25km / 2.5 hours I find I need to take in a bit of energy for training runs. I carry a protein bar for that. It has carbs too. Never used gels.

From what I can tell the most effective way for me to put myself in fat adapted mode is to do two or three (or more) 90 minute (or longer) runs a week and run those runs at a heart rate well within my aerobic capacity. Dr. Phil Maffetone is a good resource (easily found on the internet) on this.

jillmcafee wrote: »

@wabmester Thank you for the link! Powering myself on fat is what I am hoping for, so it's good to know that others successfully achieve that.

@mwyvr It looks like my new way of thinking is on track with yours. I recently realized that in spite of the fact that I run long distances, I never lose fat. I did a little self-experiment and sure enough, I have a TERRIBLE aerobic base. So I have been wearing a heart monitor during every run to keep myself in my aerobic zone. I am coming off an injury, so going slower and building aerobic fitness while I rebuild miles is not an issue for me. I'm in it for the long haul (that's why I am starting now for an HM next August!).

I like the idea of cashews or perhaps a bar with a mix of carbs and protein. I'm hoping between the lower carb diet and the aerobic runs, I will start burning through all those lovely fat stores that I have been saving!

Cardio actually has no bearing on fat loss other than that it burns calories, and long distance, steady-state cardio can actually be counterproductive due to cortisol release and muscle catabolism.

The aforementioned Dr. Peter Attia was a triathlete even before he went keto, and he was still a fair bit overweight due to his diet (and the location of most of his fat suggest low grade insulin resistance and/or cortisol driven fat storage). He actually decreased the amount of time working out in order to lose weight, even while increasing the amount of food he ate (it's all laid out in the about section).

Strength training and high intensity interval training are actually superior for both weight loss and cardiovascular health (that aerobic base you mentioned) than long, steady state runs. The glycogen-depleting and high-intensity nature of them, without the cortisol release of long sessions, prompts the body to be more insulin-sensitive, build muscle, and burn fat.

If you do the long runs because you enjoy them, though, then go for it. Being low carb will actually help your runs, since your thresholds between the points that your body can burn fat vs burning sugar for fuel will adjust such that you can burn fat (and reserve glycogen) for longer, resulting in a longer time before you bonk (if you bonk at all), and a less rough of a transition at that point. Below the marathon level, it's not uncommon for fat-adapted runners to not need anything besides water for their runs, even when completely fasted. Marathoners and above then go to a variety of portable fat sources, like nut butters, coconut butter, coconut oil, nuts, etc. Coconut oil is, in my opinion, a great option as a 1-for-1 trade (the type of fats that coconut oil consists of burn at a rate and priority similar to that of sugar, so it's also human jet fuel), though it does have the downside of going liquid at about 70F, so it does require a little bit of planning to do without making a mess.

Another good option is pemmican, which is useful if you're on a warmer run (it uses animal fats, which don't melt at quite so low a temperature) or can't eat pure fat for whatever reason. Here's a good base recipe -- http://thelongbrownpath.com/2015/07/12/pemmican-a-high-fat-fuel-source-for-ultra-long-distance-running/ Traditionally, it's what a lot of tribal hunters had when on hunts, to keep them going pretty much indefinitely until they got their quarry.

Certainly if one's goal is to improve distance running for love of running, there's no better exercise than... distance running.

What heart rate range are you targeting / planning on targeting for your slow runs?

Sounds reasonable. If you read Dr. Phil Maffetone's recommendations http://philmaffetone.com/ (he's also very pro low carb) he'd suggest you target a range between 124 and 134 as your "MAF" (Maximum Aerobic Function, his term) target range following his MAF formula:

180 (a constant) - 46 (age) = 134 as base upper range target.
Add 5 BPM if you've been training a year uninjured.
Subtract 5 BPM if you've been injured.

For several months I did nothing but running my MAF target range, usually in the upper 5BPM. It definitely helped me add more distance to my monthly training volume, without injury, and I did see improvements in pace at that same heart rate range, as Maffetone indicates would happen. It definitely felt odd at first. Forcing myself to walk hills when necessary was a bit different!

I still did the odd bit of speed work but also a ton of hill climbing as I run a lot of trails in mountains. But much of my mileage then and now is still done at my MAF range.

Many LCHF athletes with endurance runs (like marathons). They usually have a cup of coffee in the morning, then perhaps nuts after the race. I would suggest that is you are fat adapted. there was a husband wife team that rowed form California to Hawaii on LCHF. Tim Noakes has a nice youtube video on Elite athletes and LCHF. Make dsure that you are fat adapted (keto adapted) https://www.youtube.com/watch?v=6WVLrQmnnAY

Look for The Art and Science of Low Carbohydrate Performance by Dr's Phinney and Volek. The specifically address endurance and high intensity training on LCHF. Both of these doctors have been living low carb for years.