Sports Nutrition

Take Performance To The Next Level: Ø Carb Loading

Low carb ketogenic diets have been shown to help lower weight, reduce blood sugar, triglycerides and much much more. Yet athletes still think they need carbs to perform. Load up on carbs for optimal sports performance, especially for endurance sports.
There is a lot out there saying, ” you should start carbo-loading two or three days before your race and recommendations that include eating about four grams of carbs for every pound of body weight (for a 150 pound runner that’s 600 grams—or 2,400 calories—of carbs per day), including tortillas, oatmeal, bread, pancakes, waffles, bagels, yogurt, juice, white bread and skinless baked potatoes.” See a sample menu here:
When metabolically burning carbs as the primary source of fuel, glycogen helps produce energy and it helps access fat stores for long bouts of exercise/activity. A  constant supply of energy, ie carbohydrate calories,  is needed and they are needed intermittently during extended times of activity to prevent “hitting the wall”. Hitting the wall or “bonking” occurs when muscles are depleted of glycogen (stored carbohydrates). When this happens you just feel like crap. Muscles and mental acuity fail.
But WHY? Why would you do that? Why build up glycogen stores just to deplete them, hit  the wall or “bonk” and go through all that mental and physical trauma? Why? It just does not make sense.
There is a better option, a choice that allows you to burn a different source of energy, not glycogen or ATP as the primary fuel. Instead, tap directly into fat stores and burn fat as the body’s primary fuel, seems prudent for anyone who wants to lose weight or for those who prefer not to have to constantly re-supply carbs (snack ) while exercising and to avoid bonking.  Fat provides energy via  ketones ( acetoacetate and β-hydroxybutyrate ).
When you maintain total carbohydrates in a range of 25-50 grams/day (for some it may be higher) as a lifestyle, you become keto adapted (your body adapts to burning fat as its main energy source).
There are athletes who use keto adaptation to train for sports  events and improve performance,

Truth is Stephen Phinney has talked about this for years. Here are a few good links that can help get you more comfortable with fat oxidation (ketosis) and physical performance:

  1. The human metabolic response to chronic ketosis without caloric restriction: physical and biochemical adaptation. “Metabolism.” 1983, Aug;32(8):757-68.
2. Capacity for Moderate Exercise in Obese Subjects after Adaptation to a Hypocaloric, Ketogenic Diet “J Clin Invest.” Nov 1980, 66(5): 1152–1161.
3. Ketogenic diets and physical performance “Nutrition & Metabolism.” 2004, 1:2,
So what’s it going to be? Are you going to burn fat and take it (sports performance and body composition) to the next level?

About the author

Valerie Goldstein

Valerie raises the bar for health and nutrition know how with unconventional expertise and unconditional support for wellness.

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  • The naysayers to the LCKD approach to endurance athleticism say that what Volek and Phinney don’t tell you is that these athletes don’t have the same ability to then race up a hill at speed as those who carb load.
    So while the endurance cyclist will do fine when peddling for distances on a VLCKD, she will bonk compared to the carbo loaded athlete if she needs high level and long duration sprint performance. This might be true however, Volek has said that VLCKD are glycogen sparing but they obviously will not have the same stores as the carb loaded athlete.

  • Your body can only store around 250 grams of carbs as available energy. Any more and it gets stored as fat

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