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Oh boy, an article about training and diet for women, written by a man.  Like you don't have enough of men's opinions dictating how you feel about yourself, now you have to read my rant about how you should eat and train. Lucky for you, my suggestions and recommendations here are based on research conducted specifically for women, both pre-menopausal and post-menopausal, overweight, lean, insulin resistant and insulin sensitive.  Also I gleaned studies done not just on low-level walking but on weight trained and butt-kicking women.  One of the issues I have with studies that conclude this or that is that they are often conducted in such a lousy context that they only pertain to the most specific population i.e usually people who are overweight, have terrible diets and have never exercised before meaning ANY dietary or exercise intervention will improve things.  Not so in this case.

One of the major issues with people (and in this case, women) who are training hard and looking for performance benefits but want to lose some bodyfat is that there is always muscle mass, sex drive, menses and generally not feeling terrible to consider in addition to training with some intensity.  Some populations can afford to just improve food quality or drop out most carbohydrates or simple sugars and don't have to worry about whether their squat or pullup performance will suffer, all they need to do is get up and move around a bit.  Others need just enough carbohydrate to fuel activity but not so much that it inhibits fat loss.

Secondly, most nutrition suggestions for women are given by men (which is not inherently bad) but many times are given for a man's body.  Hhhmmmm.....sure, men have more muscle mass, much more testosterone, usually a greater Type II fiber distribution and overall better glucose disposal, so it just makes sense that women would do the same exact thing as men, right?  (Hint: That is heavy sarcasm).

So, what's a girl to do?

Insulinresistance

Insulin Resistant vs Insulin Sensitive

Before we even get into the real differences between women and men's nutrition, you need to take this in the context of whether or not you are insulin sensitive.  Even if you are training and eating better, if you are insulin resistant, then carbohydrates simply won't have the desired effect on your body as they would on someone with better insulin sensitivity.

What we basically want is a cell (preferable muscles and to an extent, the liver) that is receptive to insulin.  In my last article I posited the similarities between insulin activating the cells glucose transporters and a UPS man delivering a package.  An insulin resistant person takes significantly more insulin to coax the muscle cells into taking up glucose; often the cells will not uptake all the glucose and insulin, being a storage hormone, sends it right to the fat cells.  In the future, even when you ingest a small amount of carbs, you receive a huge insulin spike which not only results in rebound hypoglycaemia but develop the preference for shuttling nutrients to the always-receptive fat cells.  On top of this, insulin resistant people also have a harder time accessing stored glycogen (starch in the muscle) to fuel muscle contractions, so even glucose that is taken in may not be used effectively.

Studies have shown that insulin resistant women use up to 50% less stored muscle glycogen than insulin sensitive women during exercise.  The insulin resistant women thus relied on more of stored body fat for fuel.  More insulin sensitive women used considerable more glycogen making their post-exercise energy needs different than the insulin resistant women.

Researches concluded that insulin resistant women are...

A.  Not using nearly as much glycogen as insulin sensitive women during exercise

B.  Preferentially using fat for fuel during exercise

C.  Require much less carbohydrate post-exercise to restore muscle glycogen.

It really makes sense then, that if you are overweight and/or insulin resistant you don't need many carbohydrates to fuel exercise and probably require very little in the diet, outside of vegetable and occasional low-glycemic sources.

Tip:  If fat loss is your goal, and you are already relying on fat as you fuel source during exercise as an insulin-resistant person, why would you inhibit fat loss by eating a large serving of carbohydrates after a workout?  Focus on a LARGE protein serving, lots of veggies and quality fats like grass-fed butter, extra-virgin olive oil and coconut oil.  In fact, coconut oil makes a great post-workout fat.(More on that later).

So, What Defines Lean?  This Section Should Put Things Into Perspective

Everyone has a different definition of lean, but whether or not you are lean enough to really NEED carbohydrates post-exercise or during the day in significant amounts relies heavily on both insulin sensitivity and overall bodyfat percentage.  I would, as a rough estimate, say that needing to lose about 10-15% of your bodyweight as fat mass puts you in the not-really-needing-carbs for exercise population.

(Note:  I am going to use the word FAT a lot in the next few paragraphs but it is merely for physiological descriptions, not an insulting adjective).  

>Lets consider 3 women  and 1 man who lose 20lbs of bodyfat.

1.If you were a 150lb woman with 35% body fat (20% is usually considered quite lean for a woman), then you have approximately 53 lbs of fat mass on your body.  Losing 20lbs would put you at 130 pounds with 33lbs of fat mass on your body.   Your body fat % is now 26%, pretty darn good for women and definitely an awesome accomplishment.

2.The numbers for a 200lb woman with 35% bodyfat who loses 20lbs would now be 180lbs, with 50lbs of fat mass BUT at 28% bodyfat, not that far off from the smaller woman, because she carries much more muscle mass and thus more weight as fat still correlates to a similar body fat percent.

3.To put this in perspective, a 200lb woman with 45% bodyfat carries 90lbs of fat.  Losing 20lbs puts her at 180 lbs with 70lbs of fat mass but she is still at 39% bodyfat.

4.  Compare this to a man who is 200 lbs, and 20% bodyfat.  20% bodyfat on a man is considered not-lean in very unscientific terms.  If he lost 10% of his bodyweight as fat, he would now be 10% bodyfat (abs showing) and 180lbs.  He lost 20lbs and it brought  him from "chubby" to sporting a six-pack, so you can see the differences between men and women's physiques at work here in regards to muscle mass and what is considered "lean" for each of us.

Tip:  You may not know, or need to know your total bodyfat percent.  That's fine.  Just be realistic about how much weight you need to lose and how intensely you exercise.  You might certainly be ok with some sweet potato at lunch or dinner, but toast at breakfast, beans and rice at lunch and potatoes after a workout might be WAY overboard.  Reduce things down to one small serving of starch-based carbohydrates a day and get the rest from greens, veggies, nuts and seeds.

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Carbohydrate Use During Exercise:  The Difference between Men and Women

If you find you are not insulin resistant or do not have significant body fat to lose, then some carbohydrates certainly deserve a spot in your diet.  Keep in mind differences vary wildly from person to person and between sexes.  Research has shown many times that when exercising at similar intensities, men preferentially use glycogen (stored glucose) for energy and women tend to rely more heavily on stored muscle triglycerides and bodyfat.

Here's where anecdotal observation comes in: most trainers and strength and conditioning coaches tend to notice differences in how men and women train.  Observationally, women can often perform more reps than men at a given percent of their one-rep max but have a harder time coordinating muscular systems to really push through a high-threshold lift.  Personally, I see it often as a female trainee may literally perform 8 reps with 65lbs on the bench press and then not be able to perform one rep with 70lbs.  65lbs for 8 reps would put her at nearly 80lbs for her one-rep max, so you would assume 70lbs would be feasible.  She can certainly train to become better at lifting higher percentages, same as men, but from a baseline fitness level, she may have a harder time  performing high-intensity exercise the same as a man.

The opposite seems to appear in more metabolic type training, where women tend to be able to push past thresholds performing many reps with many exercises over and over, without losing much performance when repeating with similar weights.  Men, however, seem to put all their energy into the first few reps or sets and lack the ability to sustain that level of intensity over a long period of time.

Science?  Sort of.

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Why Do We Differ In Energy Usage?

Good question and I am glad you asked!

On a whole, research has shown that women have a greater number of slow twitch to fast twitch fibers.  Slow twitch fibers are better for endurance, fast twitch are better for short, intense activity.  Slow twitch fibers also have a greater reliance on fat for fuel and store more intra-muscular triglycerides to glycogen than fast twitch.  (Remember, glycogen is very useful for hard muscular contractions like weight lifting, sprinting and other intense activity).

Studies have shown even during sprinting and weightlifting, women still rely more on fat for fuel than carbohydrates when compared to men; since fat does not make for a great quick and intense energy source, it makes sense why it would be harder to perform really high threshold muscular contractions but easier to sustain many lower-levels contractions.  These energy systems can certainly be trained, don't get me wrong, but they do not appear to come as naturally to women as men, as evidenced by the research.

Also, intense weight and interval training relies heavily on energy use without substantial oxygen.  This is why you pant heavily after a 3 rep max squat, even though it isn't cardiovascular exercise.  After such training, the body relies on something called Excess Post Exercise Oxygen Consumption (EPOC).  This is the body's way of replenishing glycogen and ATP stores after exercise when more oxygen is available and this phenomenon increases the need for dietary carbohydrates as well as keeping overall calorie needs higher during the hours after intense exercise.

Science shows that women have both less of an EPOC need immediately post-exercise and that even with an increased carbohydrate demand, this demand shifts much more quickly back to fats as fuel than in men.  Researchers also showed that when given similar amounts of carbohydrates as men, women stored much less of it in their muscles indicating a reduced ability and need for glycogen as a fuel source.

Tip:  Even if your carbohydrate demands increase because of intense exercise, for women both your "window" of need for carbohydrates is smaller and shorter than a man's.  Translation?  One serving of carbohydrates post-workout is probably great, but you probably don't need carbohydrates at meals 2, 3 and 4 following that as your body has already gone back to fat as its fuel source.

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Protein and Fat;  How Much, How Often?

So far this probably sounds like bad and depressing news for women.  Pretty much everyone loves carbohydrates; they increase serotonin, they taste great, easy to prepare and are far more accessible than protein and fat when not at home.  But if we are reducing our carbohydrtaes, is that the end of the story?

Not so fast.  You definitely need to be in a calorie deficit to lose fat, but often times the first step should be getting the right amount of protein and fat to support hormone production, mental function and overall energy demands before reducing things down.  With a greater affinity for fat as fuel, increasing fat when decreasing carbohydrates is key.  I know, I know, fats make you fat and will clog your arteries blah blah blah.  But if you are USING ingested fat as energy and that is what your body prefers burning, then avoiding them is going to make you feel and perform poorly.  Protein also needs to be high for multi-fold reasons.

One, protein is very satiating (as is fat) and is hard to overeat due to the fact that it is so filling.  Women also have a reduced anabolic response to protein when compared to men and researchers suggest that a higher protein dose may be needed for women to receive the same muscular growth and repair compared to men.  This also makes sense because carbohydrates are protein-sparing, so when reducing carbs you'll need more protein.  Dr's. Volek, Phinney and Forsythe  heavily support the need for higher fat/protein for women in general and even recommend an increase reliance on fats over carbohydrates during menopause as well, which is something to consider .(Dr. Volek and Phinney are the lead low-carbohydrate researchers out there right now and experts in their field).

Tip:  Eat at least palm-sized portion of protein with each meal.  As Jim Laird wrote, "Yogurt is not a meal".  Chicken, beef, tuna, eggs, salmon and pork are great.  Fat should be consumed as either the amount it takes to cook the food (as in the butter or oil to saute your eggs) or a reasonable amount to coat the food (like oil in a dressing).  Use your head here...about a thumb sized portion of fat or something around a large spoonful is fine.  The rest should be an array of veggies that taste good and fill you up.

Wrap-Up

Wow, this ended up being a LOT longer than I thought it would.  I'll wrap up tomorrow with some suggestions for fat intake and why coconut oil is the bomb.  In the meantime, consider where you are in terms of activity level, fat loss need and exercise history.  A lean marathoner is obviously going to need plenty of carbohydrates day in and day out to fuel performance and will still look good and be healthy.  For the vast majority though, who want to look good and exercise a few times a week, we need to dial things down.  Keep this in perspective too:  if you are already naturally lean and maintain that on plenty of carbohydrates, then you certainly DON'T want to drastically cut them because you have an affinity for using them as fuel, whereas someone consuming a similar amount but holding a lot of bodyfat can afford to scale them back.  This is all very subjective and needs to be taken on a case by case basis.

References:

1.  Braun, Barry. Sharoff, Carrie, Chipkin, Stuart R.  Beaudoin, Francesca. "Effects of insulin resistance on substrate utilization during exercise on overweight women".

Journal of Applied Physiology September 1, 2004 vol. 97 no. 3 991-997

2.  Dasilva, SG, Guidetti, L., Buzzachera, CF., Elsangedy, HM, Krinski, K,  DeCampos, W., Goss, FL, Baldari, C.  "Gender based differences in substrate use during exercise at self selected pace".

J Strength Cond Res. 2011 Sep;25(9):2544-51.

3.    Volek, JS, Forsythe, C, Kraemer, WJ.  "Nutritional aspects of women strength athletes".

Br J Sports Med. 2006 September; 40(9): 742–748. Published online 2006 July 19

 

 

 

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