“What is your opinion on fasted training (i.e., after not eating for 12-20 hours)? I've been going through all sorts of literature that suggests this leads to biochemical adaptation, increased glycogen storage, more growth hormone released, etc. Have been trying it myself for the last 2 months, just running (5-10K) fasted, pretty good results so far.”
-B
I have typically trained 8-12 hours after eating, having done most of my training at noon after working all night and having eaten a light meal between midnight and 2 a.m. based on my below average body and my above average fight record, I think I did well for myself as a part time fighter.
Note that numerous primitive warrior societies fasted before combat and that we all did making weight for wrestling in the 1970s. Though it does not seem to inhibit competition performance, I am suspicious about development. However, I have always been more concerned with training under competition conditions and since I always fasted for competition I thought it made sense. When I train during the week after night’s sleep and a breakfast, I feel like a beached whale.
I don’t know anything about the physiology and have just gone by feel my entire life.
I usually put in my best competitive efforts after staying awake for 24 or more hours with minimal food and moderate hydration. Before I broke my metabolism in 2006, I typically fluctuated in weight twice a week from 143 up to 160.
Keep in mind, that as an adult I have always been physically week, usually injured, but effective in combat sports because I logged so many hours training to relax, to set and break rhythm and to last for a long time. I have never engaged in strength training as an adult, and gave up running after 30 to save my lower back, settling on walking and sparring instead.
I will forward this link to David, a man I coached for who actually knows how the body works on a chemical level.
There is all kind of literature on fasted training. As a runner I have always liked fasted running or "running on empty" as many say. It really depends on the athlete, his/her perspective, former adaptations (fasted or not) and what they like. I trained with a guy who always ate two sandwiches about 15 minutes before our 18 mile run. He never had any problem. I always had to be at least two hours free of food. Hydration is "more" important. It really is a question of the specific athlete.
Here's some absolutely excellent links on fasting, diet and working out.
roguehealthandfitness.com
Mangan sells books now but for years he just posted info. He takes modern research and explains it for normal humans.
stan-heretic.blogspot.com
Stan is Paleo and covers research on how carbs and sugar attack the body.