Running on low carbs.

Carb Cycling


  • going between low carb and high carb days
  • each cycle is a couple days long
  • low insulin promotes fat burning?
  • carbs important before and after workout for athletes
  • don't do it if your just getting started with keto
  • some people feel much worse when introducing carbs back in
  • might not be necessary for atheltic performance 1
  • clinical trials of carb loading before performance show mixed results 1
  • can take btw 4 weeks to 6 months to adapt


  • ways of cycling

    • seasonal
      • october to march: 20g carbs per day
      • april to september: 100g carbs per day
    • training schedule
      • high intensity: 150g
      • moderate: 100g
      • rest: 20g
  • runners: no carb, low carb and high carb days

    • no carb: easy day (1 per week)
    • low carb: regular training (rest of week)
    • high carb: hard workouts (2-3 times per week)
  • recommendation

    • timed carb diet: consume carbs before and after workouts lc1
    • eat carbs that are easy to absorb ahead of run (eg. banana)
    • eat foot with high glycemic index after a run
    • 30-60 grams of carbohydrate per hour for sports of longer duration lc2
    • 2-2.5 hours (like marathon training, ultra marathons, ironmans) may benefit from higher intakes of up to 90 grams/hour. lc2
  • example of 100g carb day

    Breakfast: Fried eggs and yogurt 28 grams carbs Snack: 1 cup mixed almonds/pistachios/cashews 16 grams of carbs Lunch: Ground turkey Chili 18 grams of carbs Dinner: Oven-baked salmon with root veggies 21 grams of carbs Dessert: 1 cup mixed blue/rasp/strawberries 16 grams of carbs


  • using multiple transportable carbohydrates (eg. fructose + glucose) better for activities of ~3h lc2
  • body can be taught to burn fat instead of glycogen for running lc2
  • typical store of glycogen is 1-2h lc2


  • source: lc2

  • reduced immunity

  • loss of muscle mass

  • decrease ability to oxidize carbs during training


  1. Carb-Cycling for Runners˄

  2. Carb Cycling on a Low-carb or Keto Diet: What You Need to Know – Diet Doctor˄

  3. Lower carb diets and running˄

  4. The Truth on the Low Carb Diet for Runners | - Bucket List Tummy˄