Fasting and Low Fuel with Exercise - What You Are Signaling Your Body to Actually Do

Don't eat before a run? Don't fuel during long exercise sessions? Fasted workouts? Intermittent fasting? Three day cleanse? How many of these fads have you seen and if you think about the success stories how many of them are men? These fads or habits are actually signaling your body to put on weight. You might see temporary results and feel less bloated but if you are going into a workout with nothing in your body you are not changing your body composition.

I'm not a doctor. I'm not a nutritionist. My education is primarily in Chemistry and Math while my experiences are in teaching, coaching and my own participation in sports. I have cited my sources below and credit the nutritional information to Dr. Stacy Sims; a leading expert in the field of women's exercise and nutrition. She is the author of a book called, "Roar" which is an excellent resource that got me interested in pursuing more information. I did lend the book out to someone a while ago and unfortunately have no memory of who I lent it to BUT if you get a chance to read it I HIGHLY recommend you read it and keep it on hand to reference. She also is a frequent guest on many different podcasts which I will link below.
 
ROAR audiobook cover art

As with most things, you might seem to notice that men have a much different experience with things like intermittent fasting and the Keto diet. Those topics have been flying around my workplace like wildfire. Multiple of my male coworkers have lost 30 plus pounds and in a very short amount of time by incorporating these into their lives. They credit this new lifestyle to feeling more energized and all-around improvement in their health. All great things for anyone! I haven't heard much about this diet change and drastic lifestyle improvements from women though. So what do we know about this? Is it really this Earth-moving new and improved way of living?

Men and women have much different responses to "low energy availability" than men. Low calorie intake, fasting, high intensity exercise with little recovery, etc.

"In the hunting and gathering days men were responsible for the calorie needs of the tribe. In times of low food availability, a low calorie diet prepared men for the next big hunt to feed the tribe while women, who were biologically lower on the food chain, retained fat in order to conserve energy." - Dr. Stacy Sims

Hmmm...sounds fair to me...

Not.

A "low energy availability" induces a stress response to the body. Where men may feel lean and clear-headed, a woman's body responds by inducing the mechanisms that retain fat. If you're intermittent fasting or cleansing you might be losing water weight or calories temporarily, but you really are conditioning your body to hang onto weight which is probably the opposite of what you are looking to do.

So what does your body need? In "Battle of the Hormones - Gender Specific Training" of the BibRave Podcast, there is a conversation that comes up about fueling around workouts. In my experience as well as the experience of one of the hosts, early morning workouts are usually done on an empty stomach. Let's face it, if I'm getting up at 4:30 to run before work the last thing I feel like doing is putting something in my stomach before I run, risking an unfortunate GI incident. But according to Dr. Sims, by not elevating your blood sugar by consuming something and by not getting your cortisol levels down in the morning you are significantly reducing the training stimulus.

"First thing in the morning your cortisol levels are high. By eating something you can reduce your cortisol and increase your blood sugar before training. If you don't then you are elevating your baseline cortisol. A higher baseline of stress means that you reduce the level of stress you can induce to your body for training. By decreasing your cortisol prior to a workout you have a larger window and a larger training load capability in your session." - Dr. Stacy Sims

So you don't need a meal, but you do need to ingest something to maximize your training capabilities. Training is all about inducing the right amount of stress pushing past homeostasis. Once you are stressed your fitness dips, but then this adaptation called "supercompensation" occurs and you have all these wonderful fitness gains! But think about it (and look at the picture), if you are continually increasing your baseline of stress you are significantly reducing the height of that supercompensation curve and not getting the most out of your training.

How to Get in Shape Fast for Your Ultimate Season

Along with consuming something pre-workout, you need to consume something within the "window of opportunity." Now, I really think that the "window of opportunity" should be called the "window of necessity." One more thing, the window for men is different than the window for women! Gasp! It's actually much more important for women than for men because a woman's body starts to break down and catabolize muscles. When asked what we should put in our body during that window, Dr. Sims simply states, "protein."

She recommends within that window to consume 20 g of protein for men and 30-40 g of protein for women. What that means is you actually have to work to get that amount of protein in you! 30 - 40 grams of protein is a lot. I've been playing around with post workout fueling for the past few days and have had to consume a significant amount of calories to meet this need (mostly because I think protein shakes/powders are disgusting). For example, this morning I did a hard workout. I ran a 10 minute warm-up, 30 minute tempo and due to having to extend my tempo in the opposite direction of home because of my trustworthy old friend, the Canadian National railway train that I frequently cross paths with, my cool-down extended to 20 minutes. A total of 1 hour with some high intensity work. Immediately, I walked into the house and ate a protein bar and made myself a two-egg and cheese sandwich on toast with some NOW® Sports BCAA Blast. After adding up the meal it came to 46 grams of protein and about 700 calories. I probably could have reduced that a little by only using 1 egg for the sandwich but overall I had to put in some actual effort to meet the needs of my body for optimal recovery.

This has been very feasible during the quarantine. I look back to what I've been doing in my own training and what has been going on with the athletes I coach. Usually I don't have the time to make myself a "sit-down" breakfast or post-workout meal. I'm on-the-go all the time plus I have a 30 minute commute back home. When I do a workout I'm usually at school. After my workout I might grab a handful of pretzels or animal crackers (whatever is available in my cupboard) and not eat until I get home and make dinner. That means I have been neglecting my recovery window majorly. This is probably true of my athletes as well. If you are familiar with teenagers they are very busy people! They might go to school, go to practice, leave practice directly for CCD, return home, work on homework, stay up and watch Tik Tok's and then get 4-6 hours of sleep. When do they eat??

There are a lot of takeaways here. Fad diets seem like a good idea and in a world of instant everything we are looking for a quick fix, but if you are a woman, you need to eat. Your body is designed to require an adequate intake of carbohydrates and by reducing calorie intake/creating a "low energy state" (fasting, cleansing, high intensity exercise with improper recovery) you are creating stress, elevating cortisol and encouraging your body to retain fat. According to Dr. Sims, "Your body can maintain a high stress environment for about 6 months. After that, your endocrine system starts to break down having an impact on your menstrual cycle." We don't know the long-term effects of these fad diets so who knows the health implications they may cause.

Lastly, if you are a parent of a teenager (girl or boy), then you need to find a way to get them access to food right away after a sports practice. Protein bars, yogurt, string cheese, bananas, granola bars, nut butters are all options but really try to find something high in protein to start the repair process. Failure to repair and recover can have significant impacts on the endocrine system. These deficiencies can impact women of all ages and lead to things like elevated stress levels, amenorrhea (lack of period), sleep issues, iron deficiency and risk of osteoporosis (just to name a few).

 Take your recovery and fueling seriously.

www.runwithcoachfischer.com

Sources

"Battle of the Hormones - Gender Specific Training" - The BibRave Podcast Episode #194

"Optimize Your Training Based on Your Gender" - The BibRave Podcast Episode #105

"Roar" by Dr. Stacy Sims

"The Everything Guide for Female Athletes - How to Navigate Your Cycle, Menopause, Cortisol and Stress, Nutrition Needs and More" - Endurance Planet Podcast 

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