How To Transition Into Low Carb Running

 In Running


Aaron is an accredited nutritional therapist, advanced sports exercise nutritional advisor and clinical weight loss practitioner. However, he is not a doctor. Please seek medical advice before making any adjustments to your current nutrition or medical practices. This article is for informational purposes only.


With the rise of low carbohydrate diets and the awareness of the inflammatory effects of sugar, it might be easy to think that you can completely remove carbohydrates as a runner, and turn up to your next training session with all guns blazing.

The truth of the matter is that many people who are involved within the endurance world have been using dietary carbohydrates, sports gels, and sports drinks for many many years.

The transition into becoming a low carbohydrate runner can be a big mental shift, riddled with disappointment. The common mistakes I see is you may continue with your current training plan, keep eating similar foods, just without the carbs, continue with your current hydration strategy, and end up light headed, fatigued or simply feeling like you’ve lost that fifth gear, lacking the speed you once had.

This article will give you some information on how to go low carb as a runner, with some simple tweaks, nutritional adjustments and training tactics. These tips will get you up and training again in no time.


The time frame you have until your next event is going to dictate whether it is a good time to switch to a low carb diet or not. Generally, this switch is best done in the off season, where building your base endurance is more important than hitting those intervals at a certain pace.

The time frame into becoming fat adapted as an athlete can vary greatly from person to person. For some, it might take 8 weeks, for others, it can take up to 6 months.

So when will you know if you become fat adapted? Well, from a recent interview with Ultra Endurance Runner, Zach Bitter on “The FatForWeightLoss Show”, he suggests that the point where an athlete is fat adapted, is when a marathon can be run without any nutrition.

Granted, he is an ultra marathon runner, but I would have to agree. Being able to run the distance of your event (marathon, half marathon) without any nutrition, you have trained well, and have reached the point where fat adaptation is occuring.

Most runners have the following scenario in their head; “I have a half marathon coming up in 6 weeks time, I haven’t started my training yet, but I was thinking of attempting this in a low carb style. What do I need to do?”  –This scenario is not going to work. Simply put, your body won’t be fat adapted.

Train without carbs using Heart Rate Zones

Training for long distance events requires a solid foundation, and to build a foundation that you can rely upon, you are going to have to put in the effort required to stimulate change in your body.

Luckily, this change occurs by unconventionally slowing down your running speed, not necessarily increasing it. There is a heart rate range where your body burns a large amount of fat for fuel, and little amounts of sugar (also known as muscle glycogen). Understanding this  range will help you tap into your fat stores and save your glycogen reserves for the tail end of your run.

If you don’t have a device that can detect your heart rate whilst running (like a Garmin, Fitbit etc), then you can simply train at a pace that you could easily talk to a running partner at, without any heavy breathing or panting. If you DO have a heart rate monitor, then read on.

For long and some medium runs, you are going to be using the following zone to build your aerobic capacity and endurance level. This zone is called the MAF zone, which was developed  by Phil Maffetone. It stands for Maximum Aerobic Function, and you must be running below this number to achieve maximum endurance:


The following calculation is simple, but there are a few things to consider:

  • If you have been sick more than 2 times in the past year, or a taking any medication, subtract 5 from that number.
  • If you have been training consistently with progression in your training for the past 2 years without injury, add 5 to that number.

So, for example, if you’re 35 years old, your calculations would be:
180 – 35 = 145 BPM


If you’re eating a ketogenic / low carb style diet, you might be wondering if you need to take anything other than water with you on your training runs. From experience, I use around 2 serves of electrolytes per hour, however you should try to work out what amount works for you on your medium runs first.

If you live in Australia, here are some common brands that make great low carb electrolytes:
– Endura (Low Carb Fuel)
– High5 Zero
– Nuun Hydration

You can make your own electrolytes by mixing Diet Salt and a little Lemon Juice together if you’re on a budget.

If you cannot find any of those brands mentioned above, you can always follow these following principles to find one that is suitable for you:

  1. Does it contain maltodextrin, sugar, honey, malt extract or fructose? If so, then it’s generally not suitable.
  2. If it’s lower than 2g of carbs per serve, then generally this is suitable. Some brands (like Endura) have 1g carbs per serve, but this isn’t going to kick you out of ketosis.
  3. Find a flavour that you like and try it out many times before the race. Don’t change your routine on race day because you risk GI distress, nausea and flavour overload, which can lead to dehydration.

Nutrition on Race Day

If you’re eating a ketogenic / low carb style diet, you might be wondering if you need to take fuel with you on your training runs. From experience, the runs that are longer than 15kms (9 miles) in distance, you might need to take something to stabilise your blood sugar levels. I have these at the halfway mark of a long run.

On the longer runs, I suggest making some type of nut butter, and buying some reusable food pouches to keep it in. A few suggestions on different nuts you could use would be Almonds, Cashews or Macadamia Nuts. I will show you how to make these recipes below:


Servings: 6


350 grams Almonds (10.5 oz)

60 ml MCT Oil (2 oz)

1 tsp Salt


  1. Preheat your oven to 180C (355F) and place all of the almonds on a baking tray.
  2. Roast for 20-30 mins until a darker brown colour.
  3. In a strong blender or food processor (such as a vitamix, nutribullet or other), place the almonds into the mixer and blend. You might have trouble with the paste sticking to the sides.
  4. Shake the paste off from the sides, and add the MCT Oil and salt. If the nut butter doesn’t come out in a liquid, experiment with adding more MCT oil or a little water to the mixture.
  5. Place into the reusable food pouches and enjoy whilst running / cycling.

Nutrition Per Serve:

Calories: 420
Net Carbs: 6g
Fats: 40g
Protein: 12g

If you don’t have a food processor and want to save some time, here are some options that you  can purchase pre-packaged for ease:
– Justin’s Classic Almond Butter
– FBomb Nut Butter


Recovery is the key to progression within endurance training. If you are training, and not fully recovering, then you’re going to be putting yourself at risk of injury and overtraining.

There are so many ways to recover, but the best way to recover your legs from a long or hard run is to use a combination of the most effective techniques:

Cold Therapy
By jumping into a cold shower or pool post workout is a great way to reduce DOMS (Delayed Onset Muscle Soreness). If you have access to an ice bath, this is even better. Not only does this help with muscle recovery, but I’ve also found that it helps recover joints that might be

Foam Rolling / Stretching
Runners in general tend to have tight hip flexors, calves, quads and hamstrings. The most effective foam rolling I’ve found is on the calves (sitting position, one leg on top of the other, rolling over your calf muscle), hamstrings, quads (superman rolling over your quad muscles),
and a hip flexor stretch (by kneeling, and pushing forward through your front knee and maintaining a tall upright posture).

Post Workout Food
Aside from replenishing your hydration levels (which is also important), following a ketogenic diet means that you’ll need to be eating enough fat to be sustaining energy requirements, so I usually finish a run by eating eggs, with either smoked salmon, bacon, avocado or even bulletproof coffee. Keep it simple. No carbs necessary.

Guest Post

Aaron Day

Recommended Posts

Leave a Comment

strength exercises