Episode 466: Dr. Stacy Sims: Why Women Can't Fast Like Men + The Training Intensity You Should Avoid

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1:53women underestimate recovery all of the time so polarized means that you're staying out of that middle zone so you can go super hard when you need to and you recover super easy so we look at the moderate intensity stuff as it's too hard to be easy and it's too easy to be hard to invoke change stay out of that you want to be hard to invoke change and you want to go easy to recover so that you can go hard again. How many times a week would you recommend someone doing this type of workout? Bare minimum, we see two sprint interval sessions or one sprint and one high intensity session and three lifting sessions a week.

2:30But you can combine the sprint and the lifting for one day in the gym. So you might do lower body posterior chain work where we're doing hip thrusts and deadlifts and then we finish off with some sprints on the bike and then you're done and dusted. Or maybe you do box jumps instead of sprints on the bike as your high-intensity work, and then you're done and dusted. So like I was saying earlier, it's about the quality of the work that you're doing rather than the volume of the work that you're doing. Why is jump training so popular? Not popular. Why is jump training so important? When we look at how bones respond to stress, we need multidirectional stress to invoke actual bone regeneration and increasing our bone density.

3:14Jumping does that because you're landing and it's complete stress in all the different planes that go up through the skeletal system, which then causes a cascade response of I need to be stronger through the entire bone. If we look at just running, it's very uniplanar and it doesn't cause that multidirectional stress. We look at walking, it doesn't either. Strength training does, but not to the extent of jump training. So if people can't jump, strength training is going to help improve bone density, especially the heavier work that you should be doing, but just plain running doesn't do it. What would be considered jump training?

3:50Like plyo jumps, like on a box? You can do that. When we're looking specifically at building bone, it's a landing, not how we've been taught with soft knees, but absorbing the impact through our bones. We're not jumping really high. We might be on a low box and jumping off as a depth jump and landing kind of flat-footed hard or doing pogo, pogo jumping, where you're flat-footed and absorbing the impact through your skeletal system. And it only takes 10 minutes, three times a week at the most to invoke change. So don't laugh, but how about just jumping on a trampoline? Because you're still going up and down vertically.

4:31But you're not getting the impact from the ground. Because our body moves when it hits the ground, the ground doesn't move. Whereas the trampoline, it moves. So you're not getting the same kind of reactive force through the skeletal system. How about, you're a nutrition scientist as well. So what is your take on women and fasting in perimetopause and menopause? If I were to use the buzzwords of fasting, I would say you do your 12-hour overnight fast. That's what you do for fasting. But when we look at it from a hormonal response, reducing stress, improving body composition, brain health, all the things that people want with fasting, for women, we need to eat within a half an hour of waking up because we have a cortisol peak and we need to drop that peak.

5:23We also see from circadian research that fueling throughout the day improves sleep, but it also improves the feedback for increasing lean mass development and dropping body fat. So when we have a big hole of no food and what happens for the most part is women will start a fast and they'll try to hold their fast till noon and then they end up working out fasted. And the brain, especially the hypothalamus, is like, what's happening here? There's no fuel for this exercise. I'm going to start breaking down lean mass because I need some amino acids for some fuel and I can't support really metabolically active tissue when there's no fuel coming in.

6:03So when we start looking at what's the best way to counter the body comp changes that are happening in perimenopause, train smart, eat, eat during the day, stop eating after dinner so you don't have nighttime snacks and making sure that two to three hours before you go to bed was your last meal. so that you can get into a deep repressive sleep. And I know sleep is fleeting for lots of people in perimenopause. So we need to work on the sleep hygiene, and maybe it's adding supplements like apigenin and L-theanine. Maybe it's cycling progesterone to help with sleep, so that you do get into that deep parasympathetic activation so that your body knows that it can change body comp.

6:47Because you cannot create change without enough calories. and without good sleep. Yeah. But again, another huge trend, as I'm sure you know, is this whole idea of fasting, fasting, fasting. And I don't understand how with hormonal issues and or just as someone who is someone who is active, how do you not eat and then also be active? If you're someone who doesn't move all day, right? Okay. And I know that I think she was on my podcast. I think you did her podcast and it all, you know, she goes on about like autophagy and how it's, it's actually really important for women to be fasting in their 40s.

7:30And this whole idea, like this is, it's actually much healthier to do it. I, and we went back and forth because, you know, I see, I can see how it is for men. I see how men respond to the fasting differently than how I've seen women respond. Absolutely. And from a physiological perspective, women have two areas in the hypothalamus that is very sensitive to nutrient density. The two areas are the arc areas and we have what we call cispeptin neurons that get expressed. When we don't have enough food coming in, we don't have all those cispeptin neurons being expressed. So we have a hit on our entire endocrine system.

8:11So that's not just estrogen and progesterone. It's also things like thyroid and our appetite hormones. Men have one area. So their sensitivity to nutrition density is not nearly as sensitive as it is for women. And I'd like to scope it down to calories per kilogram fat-free mass. Women need a bare minimum of 35 calories per kilogram of fat-free mass to be able to maintain some endocrine health. Ideally, you wanna see people up to 40. For men, it's 15. When you start to drop below that 35, for women, we start to see a lot of subclinical disturbance in endocrine and sleep and body comp. For men, when it's 15 and below, we start to see that disturbance.

8:54So there's a massive threshold difference. So when we start talking about fasting, yes, men are gonna respond because their hypothalamus is not as sensitive to low calorie. But from a biological standpoint, women are more sensitive to no calories because we're the ones that are or were responsible for reproduction, for carrying a baby, having a proper menstrual cycle, being able to support the ongoing aspect of survival of the species. So from a biological standpoint, there are specific sex differences in the brain that people don't acknowledge when we talk about fasting and fasting protocols.

9:29And so you would recommend maybe a 12-hour window at best. And how about protein? I mean, what's your idea? Because I know I think I also see that you're not someone who eats animal protein, right? You eat plant? You're not a... Yep, I'm primarily plant-based. When I travel, because I travel so much, I'll use organic Greek yogurt and or whey protein because it's readily available. So that would be the only kind of animal product I put in. For protein, we see that there is an age and sex difference in the way your body responds to exercise and protein. We see that when women start to hit 40 onwards, we are more what's called anabolically resistant to exercise and protein.

10:15So that means that we need more protein and we need a stronger dose of resistance training to get our bodies to build and maintain lean mass. For men, that starts about 50-55. So when we talk about protein and protein intake, women really need to dial it up because that recommendation that is based on the bare minimum to prevent malnutrition is still circulating as the needs for people. If you're a sedentary person who's in bed all day, every day, then yeah, the recommended of 0.8 grams per pound, that might work. But for women and men who are active and trying to rebuild and promote that body comp, we're looking at that 1 to 1.1 grams per pound as a bare minimum.

11:02And that is to stay healthy, maintain our endocrine system, and keep building bone and mass.

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13:00so i'm so surprised to hear that you are not an animal protein person because a you're so fit i mean it's insanely you're insanely fit but i mean just in terms of the satiation piece of it right like animal protein is for me it's much more satiating and plant protein i found it harder to get enough of. Are you saying it's just equally as okay in terms of building the muscle mass? Were you an animal protein person and you'd switched or what was... When I was 15, we took a field trip to a pig slaughterhouse down the five. That will do it. Yeah. So I'm well beyond 15 now. And that was the first like four way into it.

13:49I had issues back in the day because there was no such thing as plant-based. And so I've kind of fought my way through. But I've been plant-based for a very, very long time. And you go through the whole, you have to have complete proteins at every meal. You have to have X this, X that. But it's not about that. It's about the total amount of protein you have through the day and making sure that you have all of your essential amino acids. And the important part, yes, is loosing content post-exercise. And if we look at pea protein isolate, it's just on the cusp of having enough leucine. So you have a little bit of a bigger dose of the pea protein than you would the whey.

14:23But when we're talking about meal and protein in a meal, if you're taking adenami, green peas, nuts, seeds, other beans, maybe some tempeh, then you're going to get your 40 or 50 grams in one meal. And it's going to be a mix of all your essential amino acids and your golden. It's just really understanding nutrition. And I think that's one of the lacking points is the education around it. That's right. Well, because even when you said that, I'm like, well, aren't you also getting a lot more carbohydrates, a lot more fat when you're saying you're eating edamame and all these other things. It's easier to eat a piece of chicken, let's say, than to...

15:00Absolutely. Right? And so, but you said that, what's the best sources of protein that you find for people who are not animal protein eaters? The big ones that I try to get people to put in are tempeh spirulina, pea protein isolate. Yeah, spirulina is really good in iron and protein. And so for the supplement is pea protein isolate. We look at some of the fortified almond or coconut yogurts. They can be highly fortified in protein as well. So there's lots of different options. But when we're looking at carbohydrate and fat, women are afraid to eat carbohydrate. And for the most part, they don't eat enough.

15:40And if we're looking at the plant-based proteins, we're also getting a lot of fiber, which is really super important for our gut microbiome. So when we're looking at all the animal sources, yeah, they're high, high in protein, which is a great hit. But we also have to look at how are we keeping that gut diversity and also getting enough carbohydrate. So it's not one or the other. Ideally, it would be a mix. But for me, I've been plant-based so long. And through the years I've tried to put in egg or fish and I just can't do it. It's just brings me right back to my time when I was 15. At a pig slaughterhouse.

16:13Yeah. It's crazy. I know it happened to me too. What about supplements? Right? Like gross. Well, what would you say are supplements that are fundamental for women's health? Or are you somebody who don't believe in supplements? Because supplements people think is food. It's not. It's a supplement to what you're actually eating. To the things that you're eating, right. So there, I would say the big three would be creatine monohydrate for sure, because you can't eat 22 chicken breasts in a day to get enough creatine to support brain and gut and heart health. Yeah. There's so much evidence about creatine being so beneficial for men and especially for women, even in pregnancy.

16:57So that is probably my number one. Omega-3 fatty acids, really, really important, especially for perimenopausal women who are active to help with the antioxidant capacity as well as the actual cell membrane and cellular capacity. And vitamin D3, because we live in a global community of, you know, sunscreen, hats, clothing, avoiding the sun. And we live in the, you know, I live in the very, very southern part of the world and we don't get a lot of sun in the wintertime. And vitamin D is so important for every system of the body, including things like iron and iron absorption. So if we look at vitamin D, that's the third one.

17:40So those would be the top three. And then, of course, you can add things like your adaptogens if you want. Your protein powders are good. We talk about the extremes of performance enhancement type supplements. There's no real evidence for women. Things like beet juice, where beet juice became a thing a few years ago. For postmenopausal women, sweet. It works well. It helps with vasodilation. It helps improve VO2 max. But for premenopausal women, including perimenopause, it has a backwards effect because we have estrogen that's tightly tied to our vessels. And that's part of the nitric oxide cycle that causes vasodilation and constriction.

18:20So if you're introducing nitrates, it interrupts that system and you end up with a disconnect in what we call orthostatic hypotension or poor blood pressure control. Kate Wickham out of, where did she do? She's in Copenhagen now. She did research on this, looking at the differences between pre-menopausal and post-menopausal women in nitrates and saw that, yes, it's beneficial for post, but not for pre. And then things like beta alanine, it may or may not have an effect for women. So it's kind of in the, there's not enough to elucidate the evidence to be pro-women. So that's why I'm always like, okay, let's stick with the big three.

18:57And then we can do an individual basis. Did you test low for magnesium? Maybe you need magnesium. Are you on a big training block? And we need to look at how we're going to adapt to the heat or how we're going to adapt to altitude. There's some things that we can do in there from a supplement standpoint. But for the most part, it's those big three and then some protein. And then we can kind of pepper other things in on an individual basis.

19:24Thank you.