# Curious: Your Menstrual Cycle and Your Metabolism



## GoalGetter (Sep 25, 2004)

I've heard/read conflicting information regarding the effects of my menstrual cycle on my metabolism.

 Is it true, or not, that just before your period, your BMR goes up by like 200-300 calories, and is it true, or not, that the best time to burn fat is between your last menstruation and the onset of ovulation of the next cycle?

 I'm curious because I made a comment a while back to someone about being "hungrier" just before my period, and craving more food, and this person said something that sounded ridiculous to me. She said that it was OK to eat more just before your period without worrying about it because your metabolism speeds up during that time, and it cancels out those extra calories. 

 Scientifically speaking, i can see how the body might require more energy to fuel the process of menstruating, but 200-300 calories? And "cancelling out" the extra calories? 

 I was doing a search on the Internet, and came across information that both supports this theory and refutes this theory. As a result, I'm more confused now than when I started researching about it.

 So... Any of the IM experts care to chime in with some words of wisdom?

 I searched past threads on here, but maybe I wasn't typing in the right words. Nothing truly relevant to my question came up, otherwise I wouldn't have posted this question. if there IS an existing thread, please point me in that direction. Thanks!


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## bulletproof1 (Sep 25, 2004)

i have never had a menstrual cycle sorry.


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## GoalGetter (Sep 25, 2004)

bulletproof1 said:
			
		

> i have never had a menstrual cycle sorry.


 Hahaha... ok, well maybe some _other_ expert can take this one.  

 Is it a good question though? I figure other women might benefit from this kind of info/trivia...


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## dianas05 (Sep 25, 2004)

Ivy,

It is true that women burn extra calories before and during their menstrual cycle. As to how many calories they burn is different for everyone.


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## GoalGetter (Sep 25, 2004)

dianas05 said:
			
		

> Ivy,
> 
> It is true that women burn extra calories before and during their menstrual cycle. As to how many calories they burn is different for everyone.


 Thanks Diana. Not that I doubt you, but where could I find some supportive info on that, or more detail? Would you know? 

 For example, I found this article (but it's not dated, so I don't know when the research was done and if there have been new findings since then). And this guy mentions the 200-300 calorie "fact" i asked about. 

  I guess a better question would be: if it's so, then what is the best way for a woman to tailor her training and calorie intake throughout the month, going by her cycle, in a way to optimize and take advantage of the increased BMR during that time? Like what part of the cycle is the part that requires the most energy, and at what time during the month are the hormones most cooperative with exercise for burning fat...


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## dianas05 (Sep 25, 2004)

Unfortunately, I don't have any research studies to prove that it's true, but I have heard from many experts that it is for a fact a women burns more calories before and during menstruation. It has something to do with the body processing more which therefore, requires more energy. You require more iron as well because you lose so much blood. I hope this helps you a bit.


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## lorrie (Sep 26, 2004)

From what I´ve read, the body burns more carbohydrates in the first half of the cycle and after ovulation the body burns fat more easily.


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## Emma-Leigh (Sep 26, 2004)

Hmmm... I did a little research for you... Most of the research done is in relation to exercise and fuel utilisation during phases of your cycle, but there is some other stuff out there. 

I think you could probably extrapolate - increase oestrogen (seen to in the follicular phase and around ovulation) is related to increased fat utilisation while increased progesterone (in the luteal and just before your period) is associated with increased glucose utilisation.

Also - progesterone (as it is high in the luteal phase) seems to be associated with an increase in Resting energy expenditure and there is a corresponding increase in food intake in this period... So this is why you eat more just before your period...

Anyway - It might take a while to wade through but here are some articles if you are interested:
Short-term effects of a progestational contraceptive drug on food intake, resting energy expenditure, and body weight in young women1,2,3  
Glucose kinetics and exercise performance during phases of the menstrual cycle: effect of glucose ingestion  
Glucose kinetics and exercise performance during phases of the menstrual cycle: effect of glucose ingestion  Menstrual cycle phase and oral contraceptive effects on triglyceride mobilization during exercise  
Glucose kinetics and substrate oxidation during exercise in the follicular and luteal phases  
Regulation of exercise carbohydrate metabolism by estrogen and progesterone in women  
And something on protein metabolism:
Increased leucine flux and leucine oxidation during the luteal phase of the menstrual cycle in women 
And a really old paper:
BASAL METABOLISM AND THE MENSTRUAL CYCLE. 

These are also interesting:
Effects of ovariectomy and exercise training on muscle GLUT-4 content and glucose metabolism in rats 
Exercise-induced changes in circulating growth factors with cyclic variation in plasma estradiol in women


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## GoalGetter (Sep 26, 2004)

Emma-Leigh said:
			
		

> Hmmm... I did a little research for you... Most of the research done is in relation to exercise and fuel utilisation during phases of your cycle, but there is some other stuff out there.
> 
> I think you could probably extrapolate - increase oestrogen (seen to in the follicular phase and around ovulation) is related to increased fat utilisation while increased progesterone (in the luteal and just before your period) is associated with increased glucose utilisation.
> 
> ...


 Oh wow, Emma-Leigh! Thanks a ton. I'm gonna go through all these. When i was searching, I found a bunch of stuff, too, but most of it seemed irrelevant to my very specific question. I guess if I'd focused more on the hormones than the actual term "menstrual cycle" i might have gotten more relevant results. Thanks so much!


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## greekblondechic (Sep 26, 2004)

I have read that during your menstrual cycle your metabolism goes up by up to 4% and it's ok to eat a little bit more.  It was in some magazine.  I do also notice I get much hungrier on those days, some days I am ravenous like a wolf (haha reminds me of that 80's song) I'd say allow yourself to eat a little more and don't sweat it.  I truly think the body's signals are important and we tend to ignore them.  If you're hungry, your body is asking for food! But I don't think it's wise to take the liberty of actually subtracting those calories.


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## SpinQueen (Sep 28, 2004)

Hmph. Maybe if I hadn't had ammenorrhea for the past year, I'd lose a little bit of weight...


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## sara (Sep 28, 2004)

SpinQueen said:
			
		

> Hmph. Maybe if I hadn't had ammenorrhea for the past year, I'd lose a little bit of weight...



Not true... Its how you eat


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