i know the whole Atkins thing has been discussed ad nauseum, and quite forcefully too. i'm not trying to start up another round of "it's bad for you!", "it's good for you!". i just want to share my experiences, especially how it relates to cycling endurance. this is a long email, but i want to be precise.
at the beginning of the year, i started the Atkins diet. i was then about 205 lb. i was on it for two months or so, and initially lost 5 pounds but then soon gained it back. i feel i did a pretty good job at sticking to it, however my two 'modifications' were not giving up diet coke (nutrasweet/aspartame) and not giving up coffee. i found that i was hungry more than i thought i'd be, and i would have full meals plus three Advantage bars and other snacks throughout the day.
as for exercise, i ran a little...five miles, two or three times a week.
anyway, i gave up the diet and immediately gained 10 pounds!
so in june i took up cycling, bought a road bike and have (after working up to it) been doing 70-90 miles per week, about 1/3 of that some serious hills. i'm in much better shape as a result, and my cardio capacity is much improved. heck, my calves even look all muscle-y!
but i didn't lose any weight. even gained a pound. yeah i know, i probably lost some fat and gained some muscle, because i was definitely thinner.
recently, after reading about yet more positive studies on low-carb diets, my wife wanted to give Atkins a try, and so i agreed to give it another go. this time however, i decided to cut out the diet coke. rather than a extra-large size every day for lunch, i might have one or two per week, size small. the diet *does* specify that nutrasweet whacks out your blood sugar, making you hungry. i chose not to give up coffee however.
it's been three weeks, and my wife has lost five pounds and i've lost eleven. so that puts me at 205 now (from 216). i eat noticeably less than i did the first time on the diet, and my appetite is much-diminished. so i'm sticking with the thought that diet coke was doing me in. of course exercise can reduce the appetite as well. i'm not counting carbs this time because i know what to eat, so it's a more relaxed version.
when i went on the diet the second time, i was worried that my cycling would suffer. i read one post on this forum by someone who said his average speed immediately dropped 2 mph when he went on the diet.
so that first ride after starting the diet, i psyched myself out. i was exhausted half way into a route i do several times a week, and was sure i wouldn't finish. but then when i got home, i realized i was .2 mph under my all-time record for that route! i was tired because i was working hard, not because of any physical problem.
since then i've set new average-speed records on both my one-hour flat ride and a two-hour all-hill ride!
this i find sort of puzzling. i know the body can get energy from all three sources: carbs, fat and protein. so i was sure that i'd suffer a bit, but apparently i can burn fat well enough to keep me going, even on my longer rides.
mind you, i bring some diluted gatorade and some fig newtons on the longer ride, so i'm getting some carbs during the actual ride. but recovery has been ok, no worse than before.
if i were cycling 200-300 miles per week, or racing, i might have trouble on this diet. but heck, if i was cycling that much i probably wouldn't need to diet at all!
your results may vary! but i wanted to let people know that low-carb diets don't necessarily make your cycling suffer. but they don't always work either...even on the same person!