As noted a few weeks ago I went to an awesome seminar by Dr Clyde Wilson about nutrition for endurance athletes. Though I’m not much of an endurance athlete myself, I found this material pretty useful for day to day life. I’m typing up my three pages of notes so I can recycle the paper.

Energy Storage. We can store:

• about 2,000 Calories in our muscles. Muscles can absorb only glucose sugar. Maltodextrin is broken down to glucose in our saliva and is the only sugar form that can go directly to muscle.
• about 500 Calories in the liver. Liver breaks down larger sugars like fructose into glucose.
• about 200 Calories in our blood/circulatory system. Blood sugar is down to about 80% after waking up in the morning.

Burning Fuel

• Before training, stock muscle with Calories
• Muscle can burn up to 1,000 Cal/hour (intense running) but can only absorb 250 Cal/hour
• Proper hydration is critical for digestion and converting glucose into energy. Sugars need to be surrounded by layers of H20 molecules.
• The rate at which fuel enters the body is critical. Even eating the proper foods, if it is eaten all at one sitting in a day whatever cannot be converted to glucose immediately will go into fat storage.
• Body burns fat at 1/3 the rate for sugars: up to 4 Cal/minute from fat
• Compare with 10 Cal/minute for maltodextrin (direct to muscle) + sucrose (liver, then parallel delivery)
• Taking in Calories too fast will cause upset stomach.
• 250 Cal/hour works out to 4 Cal/minute. Consuming 40 Cal and then waiting 10 minutes is close enough.
• Every 1% of dehydration is a 5% decrease in performance.
• 50% of glycogen is gone from muscle after a workout

For Peak Performance

• stable blood sugar (no spikes, corresponding insulin spike will put you to sleep)
• stable fatty acid levels
• muscles fully stocked with glycogen

General diet

• We must eat protein, body can’t make it (doesn’t have to be meat though)
• Only need to eat protein 1-2x per day
• Caloric absorbtion rate: excess Calories are directed to abdominal fat (vs. subcutaneous).
• monounsaturated fats send 20% more Calories to muscle (vs saturated?)
• Fiber helps slow down digestion, this is the key to rate-limiting Caloric intake
• Spiking blood sugar -> Insulin rises to suck blood sugar out of bloodstream
• consume unsaturated fats
• consume (moderate amounts of) protein
• eat whole grain starches -> direct to muscle
• eat fruits + vegetables -> liver, then muscle
• 1/3 of Calories should come from (mostly unsaturated) fats
• dried fruit is better than nothing, but take advantage of fresh fruit whenever possible
• cook vegetables a bit to soften cellulose etc, but just a bit they should still be crunchy
• bananas are great in the AM, but get small ones or eat only half (see insulin, above)
• primary ingredient in a sports drink should be maltodextrin
• optimum is 3:2 ratio of maltodextrin to sucrose

Post Workout

• Best to take in Calories within 15 minutes after exercise
• recovery window is very important
• It takes a lot of water to digest food
• We need 1 Liter of water for 1,000 Calories
• We sweat 0.5 - 2.0 Liters / hour when training
• Need about 1/4 teaspoon salt per Liter of water
• sleep is very poor if you are dehydrated (neurons)
• Omega-3 fats, highest concentration is at synapse
• get your DRI for Omega-3 (1.5 grams/day), limiting factor for recover is the nervous system
• breakfast should have as much fiber as sugar (grams)

phew! Ideally our dietary economy and/or my cell phone would keep track of all of this stuff for me. Until then, I find Clyde’s tip sheets to be extremely helpful. Using them enables me to get relatively close to the above without thinking too much.

Link to Dr Clyde Wilson’s Blog
Link to Dr Clyde Wilson’s website (check the downloads)

Filed under: cycling, food, science |