More proof that FASTING IS GOOD FOR EVERYTHING!!
I prefer running or working out on an empty stomach. If I've eaten I feel too sluggish. Now there's a study on why that might be a good thing!
In this post at The Well blog at NYTimes.com, Tara Parker-Pope talks about a study showing that exercising before breakfast (i.e., while fasting) helps prevent weight gain and helps muscles maintain insulin sensitivity, among other benefits. I recommend the whole article but I've copied the conclusion below.
The subjects were divided into 3 groups. Group 1 ate a big breakfast and did no exercise; Group 2 ate a big breakfast before exercising; Group 3 exercised before eating a big breakfast. Groups 1 and 2 both gained weight, with Group 1 gaining more weight than Group 2.
The article says:
"Only the group that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. They also burned the fat they were taking in more efficiently. “Our current data,” the study’s authors wrote, “indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state to stimulate glucose tolerance despite a hypercaloric high-fat diet.”
"Just how exercising before breakfast blunts the deleterious effects of overindulging is not completely understood, although this study points toward several intriguing explanations. For one, as has been known for some time, exercising in a fasted state (usually possible only before breakfast), coaxes the body to burn a greater percentage of fat for fuel during vigorous exercise, instead of relying primarily on carbohydrates. When you burn fat, you obviously don’t store it in your muscles. In “our study, only the fasted group demonstrated beneficial metabolic adaptations, which eventually may enhance oxidative fatty acid turnover,” said Peter Hespel, Ph.D., a professor in the Research Center for Exercise and Health at Catholic University Leuven in Belgium and senior author of the study.
"At the same time, the fasting group showed increased levels of a muscle protein that “is responsible for insulin-stimulated glucose transport in muscle and thus plays a pivotal role in regulation of insulin sensitivity,” Dr Hespel said.
"In other words, working out before breakfast directly combated the two most detrimental effects of eating a high-fat, high-calorie diet. It also helped the men avoid gaining weight."
How about it? Do you prefer to work out fasted or with something in your stomach?
UPDATE: I've started trying to add a full-day fast (which, given my eating window, turns into a 44-hour fast) once per week. I've been jogging about 38 hours into the fast and I've felt no ill effects. Though I should add that I don't run very quickly. And after reading the article mentioned above I've completely stopped worrying about exercising while fasted; I think being mentally relaxed about it helps.
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That is so interesting. I do both. When I work out in a fasted state, I find very little difference to how i feel. Both are fine. I usually work out in the evening though and I don't eat dinner so I already have a somewhat empty stomach I guess...
ReplyDeleteI have worked out when I am on a 38-48 hour fast as well with no problems. I have just as much energy for the workout...Thanks for the info!