You're welcome DenverCruiser, please keep us updated on your progress. Your father-in-law would be proud.
Originally Posted by NoRacer
FALSE! Protein ingested during exercise may be preferentially used over one's own muscles.
Originally Posted by Tipton KD, Wolfe RR.
Department of Surgery, University of Texas Medical Branch, Shriner's Hospital for Children, 815 Market Street, Galveston, TX 77550, USA.
ktipton@utmb.edu
The main determinants of an athlete's protein needs are their training regime and habitual nutrient intake. Most athletes ingest sufficient protein in their habitual diet. Additional protein will confer only a minimal, albeit arguably important, additional advantage.
Given sufficient energy intake, lean body mass can be maintained within a wide range of protein intakes. Since there is limited evidence for harmful effects of a high protein intake and there is a metabolic rationale for the efficacy of an increase in protein, if muscle hypertrophy is the goal, a higher protein intake within the context of an athlete's overall dietary requirements may be beneficial.
However, there are few convincing outcome data to indicate that the ingestion of a high amount of protein (2-3 g x kg(-1) BW x day(-1), where BW = body weight) is necessary. Current literature suggests that it may be too simplistic to rely on recommendations of a particular amount of protein per day.
Acute studies suggest that for any given amount of protein, the metabolic response is dependent on other factors, including the timing of ingestion in relation to exercise and/or other nutrients, the composition of ingested amino acids and the type of protein.
Uh... you know how much protein 2-3g/kg of body-weight is? That's one double-cheeseburger a day! That's what he considers a "high amount of protein". Most people are eating well over this amount daily. Are you suggesting that even more is beneficial?
Notice the "Given sufficient energy intake" part. This refers to ingesting enough carbs to provide energy for the workout. This wards of muscle-catabolism due to a shortage of carbs. If Denver's going to be doing a 120mile ride, he'll probably do a couple 60-100mile training rides beforehand and burn off 4000 calories. These extra calories above his daily intake of 2500 calories must come from carbs. If not, he'll be using up his muscles for fuel. On a 2500 calorie short day, he won't have to take in as much carbs. Protein-requirements do not vary as much as carb-intake depending upon exercise level.
Also what are these "dependent factors" and what kind of "timing of ingestion in relation to exercise" creates what kind of effects on metabolic use of amino-acids? The elevated levels of adrenaline, glucagon and epinephrine during exercise will always have a catabolic effect on muscles and hinder absorption of glucose and amino-acids from the bloodstream. Protein is highly inefficient as an energy source anyway. I'm really talking about recovery after exercise when glucose-levels are low. That's when the most muscle-catabolism takes place.
What happened when he rode that 70-miles and bonked was completely depleting his glycogen stores in his muscles, liver and bloodstream. Up until that point, he was fine because he was burning mostly carbs and 20-30% fats. Stopping is the best thing to do, however, the recovery from this bonk is where damage can occur. One common mistake is not eating enough carbs immediately after a ride. Without elevated insulin and leptin levels to facilitiate absorption of glucose & amino-acids through the cell-menbranes, the muscle-tissues inside the cells will be disassembled to restore the glycogen levels. Only carbs can raise blood-glucose levels in order to stimulate insulin and leptin secretions. I'm not saying that protein is bad in anyway, I'm saying that insufficient carbs is the evil that must be combatted.