How Low-Carb Affects Your Body

Philip Pape 0:00

We've talked about the benefits of carbs for muscle , for energy , for performance but what about the detriments of a low-carb diet in and of itself ? Many times , people who are on a low-carb diet will experience energy crashes , stalls in their weight loss , stalls in their performance in the gym , and there's a reason for this that we don't often talk about . That has to do with cortisol and your metabolic rate . So today we are talking about how your quote-unquote healthy low-carb diet might be working against you , and then how to have a more flexible approach that you're probably going to enjoy more anyway and will help you get the results you want . Welcome to Wits and Weights , the show that helps you build a strong , healthy physique using evidence , engineering and efficiency . I'm your host , philip Pape , and today we're talking about carbs again , but from a different angle . There is a connection between lower-carb diets and both cortisol and your metabolic rate . That I think is really , really important and causes things like stalled fat loss , like crashing energy , feeling unusually stressed , and many people experience these symptoms , but they don't connect them to their carbohydrate intake . The research now suggests that there is a physiological reason for this . There is a hormonal chain reaction that can slow your metabolism and potentially make fat loss harder , not easier . Obviously , anything that reduces your expenditure , your metabolism , the amount of calories you burn every day , is going to make this harder , because you're going to have to eat less , potentially to maintain the deficit , or you're going to have slower fat loss at the same intake . And , of course , the less you eat , the less energy you have , the hungrier you are . There's a cascade of things that are just not good . We always want a higher level of energy , a higher level of energy flux , even when we're trying to go for a fat loss . And while the keto community , the low carb communities , everyone who's just low carb , maybe even carnivore they often dismiss these concerns or they say that there are other reasons . The evidence is becoming harder and harder to ignore , not to mention the outcomes . Right , when we see something like people on higher carb diets can build a lot more muscle , there's a reason they have more energy coming in , more recovery ability . But there are also negatives in the other direction when you have low carbs that prevent the fat loss you're trying to achieve .

Philip Pape 2:25

And I'm not here to demonize low carb approaches . I never do . I never demonize low carb in and of itself . What I say is that you want to eat in a way that supports what you need and what you want , and many people . What they need is more energy , more performance , more recovery . They want to build muscle . What you want is foods that you enjoy , a lifestyle right To be able to go out to eat , to be able to not say no all the time . So when you combine these together for most people that generally means moderate to higher carbs and you can absolutely get all the amazing body composition results you want . Doing that . We talk about it all the time .

Philip Pape 3:00

So I'm not here to demonize low carb . I want to look at it through the lens of evidence and engineering to find a balanced , sustainable approach for you . So you understand what you're getting into . And before we get into all of that , if you just want the guide to learn exactly how to set up your macros and your calories and everything else , I do have a guide that is super popular . It's on flexible dieting and you can use the link in the show notes or go to witsandweightscom slash free , I think . On that page . It's called Nutrition 101 for Body Composition , but it's the same idea . It will help you implement the principles we discussed today in a very practical , step-by-step way for you and just go download that using the link in the show notes .

The Cortisol-Carb Connection

Philip Pape 3:39

So let's talk about this . I'll call it hidden connection between your carb intake , your stress and your metabolism . And it helps to understand what happens in your body when you significantly restrict carbohydrates , because at its core , your body receives or perceives severe carb restriction as a form of stress . The fact that you don't quote unquote need carbs to survive is a red herring , right , because we're not trying to just survive , we're trying to thrive . We're trying to have all the things that we want to achieve our goals and live a great life .

Philip Pape 4:13

And research has consistently shown that low carbohydrate diets increase cortisol . What is cortisol ? It's effectively the stress hormone , and a study published in the Journal of Clinical Endocrinology and Metabolism found that , when compared to a moderate carb diet , low-carb approaches led to significantly higher cortisol concentrations over an eight-week intervention period . And cortisol is what allows you to respond to threats . So when your carbohydrate intake drops too low , or it's intentionally low , your body faces a few challenges . First of all , glucose availability for your brain and muscles goes down . Secondly , your body has to find alternative fuel . And thirdly , this then requires substantial adaptation in your metabolism , and all of these trigger a stress response . There is research that shows cortisol levels consistently increase on a keto diet , and keto is essentially an extreme form of carb restriction , and the reason this matters is because chronically elevated cortisol is linked to a ton of negative effects .

Philip Pape 5:15

I know we've talked about stress often on this podcast , but it can't be understated how impactful stress is to your metabolism and , conversely , to metabolic dysfunction . When it's high and low-carb , folks are going to say that , hey , you know , this is going to be temporary . Right , this cortisol increase is temporary . It's part of adaptation and there's always some truth to that when there's ever any change to your lifestyle . But for many people , especially when you have other forms of stress , which is pretty much everybody , every human being who has work , family , even your training , is stress . This is just additional hormonal strain on top of that stack of stress . That is going to become problematic when you sustain it right , when you sustain it , and this is regardless of weight loss . Okay , so we're not even talking about just when you're in a calorie deficit . We're talking about when you're not in a calorie deficit and you're restricting carbs . It is going to increase your cortisol levels compared to a moderate fat or moderate carb diet , right ? So , in other words , the cortisol response is not about the weight loss . It's specifically related to the carb restriction . And that's what brings me to an important point . It's specifically related to the carb restriction , and that's what brings me to an important point .

Philip Pape 6:26

Your body does not distinguish between different types of stress . Yes , there's all the chronic perceived stress in our life , like your deadline at work . There's the hormetic or acute stressor , like your intense training session . There's stress from doing too much cardio some of us have right and then there's stress when you're dieting . But when you're not dieting , there's also stress from severe carb restriction , regardless . And guess what ? It all triggers the same hormonal cascade your cortisol levels remain chronically elevated , and then this affects your metabolic rate , which is the next piece of the puzzle , okay , so that's why this is important .

Impact on Your Metabolic Rate

Philip Pape 7:04

We've established that low-carb diets increase cortisol . Okay , even is the next piece of the puzzle . Okay , so why ? That's why this is important . We've established that low carb diets increased cortisol . Okay , even in the absence of a calorie deficit .

Philip Pape 7:09

So where things get interesting here is that your metabolism , which is made up of multiple components , one of which is just your BMR , your basal metabolic rate , which is like two thirds of your daily calorie burn . It's the foundation of your metabolism . If your cortisol is sustained and it's high , right ? If , if , what am I trying to say ? If you have sustained high cortisol , it is going to suppress your thyroid stimulating hormone , that's your TSH , the production of your TSH , and that then impacts the thyroid hormones that regulate your metabolism . So your thyroid gland right , which is in your neck it's like that butterfly shaped gland . It produces hormones that control how quickly your body burns calories . So it's like a thermoregulator , some people call it , and when cortisol interferes with that , then your metabolic rate is going to slow down . It's all a cascade , right , and so we don't know the exact impact .

Philip Pape 8:01

But for someone with , like , a resting rate of , let's say , 1200 to 1500 calories , if you had a 20% suppression , then that would be like up to 300 fewer calories a day and that's almost like 30 pounds of weight gain every year or lack of weight loss . You know what I mean Like just to give you the numbers . A few hundred calories a day can make a big difference to many of us , especially smaller people , women , petite women like , whose rates are fairly low . Now it just makes it lower , it makes it even harder .

Philip Pape 8:31

Also , this isn't just about cortisol , because when you cut carbs , a few other things happen to your metabolism . The first thing is that your body becomes more efficient at conserving energy , and adaptation that's effectively designed to keep you alive during food scarcity and the lack of carbohydrates can give your body the feeling that it doesn't have enough nutrients or enough food or enough energy , even when you're not in a calorie deficit . Again , I'm trying to hammer home the point that this is above and beyond and independent of dieting itself . This is the low carb aspect of it in and of itself . The second thing is that having low carbs means you're going to deplete your glycogen very quickly . That could also result in water loss and , you know , give you the phantom appearance that you've lost weight because it's glycogen , it's water weight , and then it masks what's actually happening , creating the illusion of progress when your metabolism might actually be slowing . And so this is a big problem when you go from higher carbs to lower carbs very quickly . Sometimes that actually happens on purpose when you go into fat loss phase , but when you understand that that happens , it's fine .

Philip Pape 9:39

The problem is that the glycogen depletion also affects your workouts , your performance , your energy , all of that . That's a different issue , but it still adds to the stress . So if you don't have to be on lower carbs even when you're dieting , it can be helpful . This is why I sometimes ask people to trade off some protein and carbs , depending on the energy that they need . The third thing here is that when you have long-term carb restriction , the research has shown that this can reduce your T3 thyroid hormone , and that is yet another , let's say , dampener on your metabolic rate , affecting everything . It affects everything . It affects your stress response , your mood , your digestion , your immune system , your libido , of course , your metabolism and then your energy levels . It's all connected , right , and then we've talked about this on other podcasts , so it wasn't really part of today's episode .

Philip Pape 10:30

But just remember that

The Scientific Evidence

Philip Pape 10:32

muscle breakdown , also called catabolism , right , when you have more cortisol , it's going to increase the breakdown . It's like your body's way of trying to grab energy wherever it can . And since muscle tissue is metabolically active , of course , and you lose it , it's not good . It's not good when you lose muscle , which is going to just further reduce your calorie burn as well . So when you combine all these changes from low carb , just losing weight , losing fat is going to be progressively harder over time , simply because you were on lower carbs , and that's why a lot of people get initial success with these diets and then they hit these huge plateaus .

Philip Pape 11:08

I used to think it was just because , oh , you're losing water weight fast , so you think you're in the right deficit . Then that slows down . You're no longer in the deficit . You feel like you're in a plateau . Really , you just need to lower the calories . No , it's actually a lot worse than that . It's a lot worse than that . There are actually compounding effects above and beyond that related to the cortisol-carbohydrate connection . So you know , those are the issues .

Philip Pape 11:30

When you have carb restriction and a lot of people listening to the show or maybe this is the first episode you've ever heard you're like well , what else do I do ? I've heard that cutting carbs . You know carbs make you fat . Right , that's a myth . We know that's a myth . At this point , energy balance is what caused you to get fat or lose weight . It has nothing to do with carbs , just has to do with calories . But we know people have been conditioned to think that carbs are bad in some way .

Philip Pape 11:54

The answer is that there is no one size fits all answer that your individual and ideal carb intake is going to depend on a lot of factors . If you are sedentary , you don't need nearly as many carbs as if you're active . Of course , if you're listening to this show , strength training is non-negotiable , and strength training requires a lot of carbs to really make the most of it . Walking is something you should be doing as well , and so you should be active . Right , and you're trying to support your metabolic health . You're trying to maintain your stress levels . You're also trying to eat food you enjoy , so that it's sustainable Food that's satiating , like high-fiber foods . Well , what are high-fiber foods ? Well , a lot of carbs . Vegetables , fruits , grains contain fiber . Right , also , just having a delicious , energy-promoting meal that's balanced between fats , carbs and protein . You're still going to have carbs , so there really is little to no benefit in cutting carbs for the vast majority of people when you're not dieting .

Philip Pape 12:49

Now , when you are dieting meaning you're in a calorie deficit the calories are going to come down . You're going to keep the protein high , you're going to keep the fats moderate and you may end up with fairly low carbs . This is why you don't want to diet at too fast of a rate If your metabolism is fairly low to begin with and you have unrealistic expectations , and so you go in an aggressive rate of loss . Your carbs are going to come way down and you're going to start to see some of these independent low-carb or carb restriction-caused issues . And that's the message of today's podcast . That is why I wanted to make this , so that you understand that restricting your carbs has its own detriments , above and beyond detriments from other things , and it can exacerbate your metabolic decline .

Philip Pape 13:32

So , if you're listening , even if you're a client , if you're in our physique university we've talked about this many times and you're in a fat loss phase , think about the rate of loss , like how many calories do you actually have to play with , because just being super low calories like 1,200 , 1,100 , 1,000 , could be where the problem is and also think about how many carbs you have in there and when you're eating them . Are you eating them around your workout ? Little fixes like adding 20 grams of carbs and taking it from protein , or even some from fat , could be exactly what you need to avoid some of these issues , and we also have studies showing , I'll say , the other side of the same coin , in other words , what happens when you increase your carbs . Well , again as part of a healthy whole food diet , right Dietary pattern . I don't mean processed carbs like pizza , donuts , muffins . Those aren't carbs right . Those are processed carbohydrates , fats and sugars . That's not carbs right . Carbs would be an apple or a whole grain piece of bread is a carb .

Philip Pape 14:30

Studies show that increasing those carbs may reduce circulating cortisol and then dampen the associated psychological stress-related responsiveness . Psychological stress-related responsiveness Do you know what I just said ? So your cortisol becomes more sensitive to your psychological stress when you have more of it circulating in your blood and that happens when you have less carbs . But if you increase your carbs you actually reduce the cortisol and that can have a big impact on your fat loss and how you feel . So for most active individuals , if you're training , if you're walking , moderate intake , which usually amounts to about I don't know 30 to 40% of your calories I don't think in terms of percent calories I like to anchor my protein , anchor my fats and then the rest is carbs , which usually provides a nice balanced approach , gives you plenty of glucose to support your thyroid function , to obviously support your training too . It keeps cortisol in check and then allows for fat loss when in calorie deficit because you're keeping it moderate .

Philip Pape 15:29

Now , carb timing can make a difference . I mentioned this a couple of times . But if you place most of your carbs around your workouts , also in the evening before bed not like right before bed , but in the evening , like with dinner those are two times that are going to help you with your performance , with your recovery and even your sleep quality . You with your performance , with your recovery and even your sleep quality . Right , there is research that adding some you know nutritious carbs at night can help you with your sleep quality and manage cortisol levels . And I had a client who was like right on the verge of feeling kind of wiped out with their workouts and all we did is we just swapped a little protein for carbs . We're talking like 10 , 15 grams . It was not much at all , but it was enough . It was enough .

Philip Pape 16:06

And you don't know until you experiment with it . Track the data , compare the before and after , compare your biofeedback , like your energy , your workout performance , like how many reps did you get ? How did you feel ? Did you feel recovered ? Did you get sore ? Look at your sleep quality , your HRV , things like that , your just general feeling of like chronic stress , your food cravings yeah , we forgot to mention that , but food cravings and hunger signals are all impacted by this as well .

Philip Pape 16:32

And then , of course , you know are you making progress ? Are you able to make the progress you want ? Right , and it doesn't mean , hey , you have to start cramming your mouth with tons of carbs and eat pasta and bread and eat like a bodybuilder diet with like 600 grams of carbs . Right , you still care about , okay , the quality of it and the quality of it being reasonable . Minimally processed foods are always a good start to add in , like fruits , potatoes , rice , oats . They provide energy , fiber , micronutrients , sometimes hydration . So all these just support your health in so many ways . Right , we're not trying to swing into eating all processed foods that some people call quote unquote carbs that are not , but really a nice , balanced , whole foods based , nutritious approach . I don't see how anybody can find that unreasonable , but you'd be amazed , or maybe you wouldn't . You see it on the Instagram all the time People demonizing fruits and carbs of any kind , talk about how carbs make you fat All the myths that still persist today .

Philip Pape 17:23

Now , if you want to put this into practice , I'm going

Strategies for Optimal Carb Intake

Philip Pape 17:30

to give you some strategies . Okay , first , if you've been on a very low carb diet for a long time . We're talking about like 50 grams a day or less then I want you to honestly assess your biofeedback right your fatigue , your mood , your sleep , all of that and then gradually titrate up your carbs and see how it changes . Don't do anything else and keep your calories the same too . So that's the key here is like keep the calories the same , but increase your carbs . Take it away from fats first and then protein . I mean it's kind of weird . Like a lot of people with a low carb diet also don't even have great protein , they end up having a lot of fat , right . That's what I see . That's like the keto diet . So you may have a lot of room to bring the fat down . Replace it with carbs . And the key word here is gradual , because here's the other thing I get right .

Philip Pape 18:10

People are like oh , I added in carbs and I had bloat and I had like digestive issues and I had this and that . Well , yeah , because you're massively changing not only your patterns and your habits from your body's perspective , but you're introducing like you're flooding it with things that it's just not used to . Same thing with your gut right and the gut bacteria , the gut health , all of that . So don't blame the carbs , blame the method to reintroduction . Your body needs time to readapt . So I would add like 25 grams of carbs tomorrow , right , for the next week , and just leave it there and then add another 25 grams a day the next day , like however many grams , to get you to your your goal , because this is also going to prevent , like blood sugar spikes that you're not used to , especially if you're not eating balanced meals . If you are , it's not as much of a concern . It gives you a metabolism some time to adjust . It lets you see what's really working . So that's the first strategy is just like this gradual reintroduction .

Philip Pape 19:04

The second thing is pay attention to the timing . We mentioned it before , but I just want to be very specific , right ? Having some carbs in the evening can help reduce cortisol , and eating carbs around your workout is going to match your activity level , your training days or your training , especially for those intense sessions . You're going to notice a difference . Most likely . I don't recommend anybody train fasted unless you know for a fact that you perform more optimally , which is very , very rare , right , and it's going to help with your stress as well . Um , on rest days , yeah , you , could you reduce carbs , lie and do some slightly and do carb cycling . Maybe . I generally recommend most people just keep it consistent day to day and then um see if it to change , to deviate from that , but just start there , all right .

Philip Pape 19:47

The fourth strategy here is really , um , I'll call it periodic carb cycling . I'm not talking , this is so . This is different than daily carb cycling . This is , uh , over time , right , so like over as little as like a week , um , but it could be multiple weeks where you follow , like , a higher carb approach and then a lower carb approach and see if you notice a difference . And I only like that so that you can both play around with what refeeds feel like , like how , when you flood your system with carbs , what it does for you , but then also see the difference when you do restrict carbs and build that sensitivity . This is more of an experimental thing to see , like prove to yourself that there's a certain optimal level of carbs for you .

Philip Pape 20:35

The fifth strategy here is to be aware of all the other things stressing you out , because if you're under lots of , like perceived or psychological stress , if you're not sleeping well , if you're over-training , over-exercising , this is going to sound weird . But rather than me tell you to eliminate all that , because I know it's difficult . It's a process , right , you might just need more carbs to offset it , to mitigate your stress load . Sounds strange , I know , but all of this stress is cumulative when it comes to your cortisol . So , at the very very least , not restricting carbs when you have all those stressors is a good start . But even Flooding your body with more may be the way to go .

Philip Pape 21:12

And the reason I included this in here is a lot of my clients come to me like they're just stressed , they're under eating , they're not training right , and we want to get them doing all these things . But one of the first things I have them do is start tracking their food and try to eat more carbs that's usually what happens or more protein as well . You know cause I'll have , I'll have female clients . I can't eat that many carbs . I can't eat a hundred grams of carbs , or I can't eat 200 , whatever it is . And I'm like it's okay , we're going to titrate up right ? Here's some ideas , here's some lists let's start incorporating . And a lot of times they're like oh my gosh , like I feel so energized . I feel like I can do so much . I feel like I've got a new lease on life . You know I'm not . I'm not gaining weight , but I'm feeling better , I'm able to push more in the gym . It starts to Like offload some of the stress for them and and that's why we know that there's this hormonal connection with carbs , right ?

Philip Pape 22:04

The last thing is you want to track all the things you care about when comparing lower to higher carbs . So energy levels , sleep quality , workout performance , well-being , mental health , it doesn't matter , you pick it , pick what those are . I have a set of markers that I use with clients , but you may want to track whatever makes sense for you Hunger signals , et cetera . The goal is to find that sweet spot , right ? You don't have to eat lots and lots of carbs , but generally a low or very low carb approach is not going to work for most people . Whether you're a man , a woman over 40 , under 40 , it doesn't matter . Don't tell me hey , I'm a woman over 40 and peri-postmenopause , so I've been told I need to eat low carbs . No , usually it's the opposite . Usually you're not eating enough carbs to support optimal hormone function , metabolism . You're impeding your fat loss progress . Eat those carbs , all right .

Philip Pape 22:58

So the neat thing about all of this is the body is complex , so these relationships tend to be bi-directional . You know like the cortisol levels

Finding Your Personal Carb Sweet Spot

Philip Pape 23:01

reflect how your metabolism is varying , right , independent of psychological stress . And we know that baseline concentrations of plasma cortisol actually vary with your metabolic rate based on your mass , like based on your body mass . So what this means is that cortisol is not just influencing your metabolism , it is a component of your metabolic process . It actually regulates the energy production and utilization in your body , very much like thyroid . Right , it's bidirectional and that means it suggests that optimizing metabolic health is not about your macros or calories . It's about creating the best lower stress hormonal environment to support efficient energy flux , energy production using the energy , using the nutrients .

Philip Pape 23:50

And so when you maintain the right carb intake , you are you're not just doing all the superficial things , you know , fueling your workout , satisfying your cravings , blah , blah , blah You're supporting the hormonal cascade that keeps your metabolism humming . And then you know acute stress . Yeah , that can suppress appetite in the short term , but chronic stress can increase your consumption of highly palatable foods , especially carb-rich palatable foods . Interestingly , you know , carb-rich , fat-rich , sugar-rich , and that can increase your visceral adiposity , which is your belly fat , cause weight gain , all the things . And that also explains why extremely restrictive diets usually lead to rebound , overeating and then weight regain Another reason we don't want to restrict carbs .

Philip Pape 24:34

So if you can find that sweet spot of your carbs , then you're kind of optimizing this whole ecosystem in your body that determines your body composition and your energy , your longevity , your health , all of it . So carbs are not good or bad . They have a role in your body's hormones . It's hormonal milieu symphony , whatever you want to call it , and it's a really different way of thinking about them . They're a tool , and learn to use the tool . For you .

Philip Pape 25:01

The goal is not to swing from one extreme to another here . I don't want to demonize carbs and I don't want to consume them indiscriminately . I'm definitely not going to demonize them , if you know me right , but I also don't want to think well , just , you have to eat like all these carbs . There's a thoughtful , individualized approach . I know a few folks who've been lifting a long time and they know the value of carbs and they also can't take a lot of carbs . And and they know the value of carbs and they also can't take a lot of carbs , and they've tracked it and they've compared it and they've done all the things we've talked about and they've arrived at the fact that , yeah , you know what ? I'm actually better on higher protein and moderate carbs . Somebody else is better on normal protein and super high carbs .

Philip Pape 25:37

The fitness industry loves to sell simple , black and white solutions . Carbs are evil , fat makes you fat . All that , Just throw it away . Unfollow . Listen to this show . Reach out and understand that there is nuance to all of this your diet , your hormones , metabolism and that helps you make the informed choices that get you the results you want . All right .

Philip Pape 25:56

So again , if you found value in today's episode , if you want to learn how to settle this up just very simply your macros , your calories , your timing , your carbs download my free flexible dieting guide . Use the link in the show notes or go to witsandweightscom . Slash free Again . It might be called Nutrition 101 on that page , but the flexible dieting guide is gonna help you implement the principles we discussed today Very step-by-step , simple , personalized to you , to support your metabolism , help you achieve your physique goals without all of this restriction or all of this stress . All right , until next time . Keep using your wits , lifting those weights and remember that strategic carb intake can help keep your stress in check and your metabolism firing on all cylinders . I'll talk to you next time here on the Wits and Weights Podcast .