Females and Intermittent Fasting

Game8

Has any female here who follows Intermittent Fasting (IF) thought to look into the role hormonal differences play when it comes to fasting? Most of the benefits you read about were shown in studies with male subjects, but does the same apply to females?

I never thought to look into IF's effects on males vs females until someone brought it up recently, and to be honest it doesn't look too good. It seems as if all the good things about doing IF for males don't apply or even apply negatively to females.

For example, increased insulin sensitivity, decreased hunger, increased sex drive and increased muscle adaptation were all observed in male subjects under fasting. But none of these things were observed in females and some of these things had NEGATIVELY correlated with fasting when done by female subjects. So it seems females respond much better when fed.

agentphantom

my spouse and I have been on the if for a few months now and she has not experienced any of the "negative" things you mentioned. it's working great for her.

BusyRaeNOTBusty

I tried it. 16 hour fast, 8 hour feeding window. I got headaches. I can do a 14 hour fast, 10 window, but I don't really call it "intermittent fasting" just "skipping breakfast".

Chief_Rocka

Martin Berkahn mentioned women going better on a slightly shorter fast for hormonal reasons, I don't know what his basis is.

HeidiMightyRawr

I think it's a good idea to look into it, so you have some understanding of the benefits / negatives in IF.

I do think it's a personal thing though, I know of women on here who get on great with it. I on the other hand am not even willing to try it! I get dizzy spells when I've not eaten in a while, and am hungry quite often!

Game8

Seemingly good results are sometimes due to placebo effect or some other factor. Which is why we have controlled studies to give definitive answers.

lasmit4477

Glad you posted about this. You know I was curious about it and had questions about the hormonal effects for women.

Game8

Glad you posted about this. You know I was curious about it and had questions about the hormonal effects for women.

The credit goes to you for bringing up the question in our email discussion!

lasmit4477

Glad you posted about this. You know I was curious about it and had questions about the hormonal effects for women.

The credit goes to you for bringing up the question in our email discussion!

Indeed! Just glad you took the time to research it when I brought it up.

risenonlytofall

I think shorter fasts work better, at least they do for me. Eating breakfast kills my will to live, but so does skipping lunch. I'd love to see more scientific evidence, though.

pullipgirl

I've been doing this for months, the only side effect I have is that I don't feel hungry anymore. Sometimes I feel like I have to force feed myself.

Game8

I think shorter fasts work better, at least they do for me. Eating breakfast kills my will to live, but so does skipping lunch. I'd love to see more scientific evidence, though.

■ One study (1) found that while IF improved insulin sensitivity in male subjects, female subjects saw no such improvement. In fact, the glucose tolerance of fasting women actually worsened.

■ Another study (2) examined the effect of alternate day fasting on blood lipids. Women’s HDL improved and their triglycerides remained stable; men’s HDL remained stable and their triglycerides decreased. Favorable, albeit sex-specific results.

■ In another study (3) both men and women displayed greater increases in VO2 max and resting muscle glycogen concentration in response to fasted cycling training, only men showed greater skeletal muscle adaptations when fasted. Women had better muscle adaptations when fed.

(1) http://www.ncbi.nlm.nih.gov/pubmed/15833943?dopt=Abstract
(2) http://ajcn.nutrition.org/content/81/1/69.abstract?ijkey=83db7f2dc04b6eac3949f1818e9fe5f6e9395a82&keytype2=tf_ipsecsha
(3) http://www.ncbi.nlm.nih.gov/pubmed/20452283

risenonlytofall

I think shorter fasts work better, at least they do for me. Eating breakfast kills my will to live, but so does skipping lunch. I'd love to see more scientific evidence, though.

■ One study (1) found that while IF improved insulin sensitivity in male subjects, female subjects saw no such improvement. In fact, the glucose tolerance of fasting women actually worsened.

■ Another study (2) examined the effect of alternate day fasting on blood lipids. Women’s HDL improved and their triglycerides remained stable; men’s HDL remained stable and their triglycerides decreased. Favorable, albeit sex-specific results.

■ In another study (3) both men and women displayed greater increases in VO2 max and resting muscle glycogen concentration in response to fasted cycling training, only men showed greater skeletal muscle adaptations when fasted. Women had better muscle adaptations when fed.

(1) http://www.ncbi.nlm.nih.gov/pubmed/15833943?dopt=Abstract
(2) http://ajcn.nutrition.org/content/81/1/69.abstract?ijkey=83db7f2dc04b6eac3949f1818e9fe5f6e9395a82&keytype2=tf_ipsecsha
(3) http://www.ncbi.nlm.nih.gov/pubmed/20452283

Thanks!

sistermine

I've been doing 2 "fast" days (500 calories) and 5 days of normal eating (~2000) for 10 weeks, and had no ill effects. Haven't tracked blood lipids or glucose, but am definitely losing belly fat, and have lost about 1lb per week on average. Much prefer the occasional fasts to constant restriction.

The studies I've read haven't pointed out any difference between men and women; I'm definitely interested in this, so will look at the quoted research. The American study I read was on weight-loss-focused "alternate day fasts" (same 500 calorie restriction idea but every other day) designed for obese women, and seems to show good blood-glucose and -lipid results compared to daily calorie restriction diets - i.e. same weekly calories overall, similar weight loss, but better physiological results. However, it didn't say anything about muscle or other physiological factors.

I'm personally a fan of the IF idea because it restricts the self-denying to some of the time rather than the usual calorie restriction diets which restrict you all of the time. And so much of what makes people stick to diet and exercise regimes is in our heads, so anything that works in the long-term is good in my book. Whether I can keep it up is another question, of course...

Game8

I've been doing 2 "fast" days (500 calories) and 5 days of normal eating (~2000) for 10 weeks, and had no ill effects. Haven't tracked blood lipids or glucose, but am definitely losing belly fat, and have lost about 1lb per week on average. Much prefer the occasional fasts to constant restriction.

The studies I've read haven't pointed out any difference between men and women; I'm definitely interested in this, so will look at the quoted research. The American study I read was on weight-loss-focused "alternate day fasts" (same 500 calorie restriction idea but every other day) designed for obese women, and seems to show good blood-glucose and -lipid results compared to daily calorie restriction diets - i.e. same weekly calories overall, similar weight loss, but better physiological results. However, it didn't say anything about muscle or other physiological factors.

I'm personally a fan of the IF idea because it restricts the self-denying to some of the time rather than the usual calorie restriction diets which restrict you all of the time. And so much of what makes people stick to diet and exercise regimes is in our heads, so anything that works in the long-term is good in my book. Whether I can keep it up is another question, of course...

I'm aware of the study you mentioned. IF does seem to be beneficial for obese women, but the results may not apply to leaner people or women of reproductive age.

DeanBocari

Here's a video clip on the impact of insulin when the body is in a fasted state: http://www.youtube.com/watch?v=TKJXBTeBrgU&feature=share&list=UUN3PpCtqfVBbcfSZw0kKwgQ

Feel free to get in touch with any questions at all.

-Dean