Can we channel evolution to lose weight for us, through the miracle of starvation mode?

“I just think I’m not eating ENOUGH to lose weight”.

I hear this a looooooot. And I want to help. In this scenario, it’s very easy to blame something called “starvation mode.” Starvation mode is this idea that if you reduce your calories, your body will go into starvation mode, which will stop you from losing body fat no matter how low you drop your calories. The idea is that your body fights back and goes into this mode to help you survive. 

Is this ACTUALLY what’s happening?

Maybe. Maybe not.

You’ll just have to listen and find out.


Welcome back to the Bite Me Podcast. Today I wanted to talk to you about something called starvation mode. You may have heard this phrase being used, particularly in a weight loss setting, and essentially it's this belief that your body is going to fight back against weight loss to protect you from dying, and this is an adaptation that we, as mammals, as human beings, have developed from times of famine, our body has developed this starvation mode that it can engage when our calories, our energy, our food intake gets too low. It's freaking out, it thinks we're going to die, so instead we flip into starvation mode and it stops us from losing any body fat. And so you'll often hear it getting blamed for inability to lose weight, to lose body fat, particularly if people are trying to lose that "stubborn fat," they feel like they've had some success losing body fat, but getting the last bit off can be quite tricky, and often enter starvation mode, that's the reason that we can't do it. Now I think I came up with this quote, I'm claiming it anyway, but I general really respond with, "If starvation mode existed, people wouldn't starve." And the unfortunate reality in lots of countries is starvation is a very real threat, and unfortunately lots and lots of people die from starvation every year. If starvation mode did truly exist, surely their bodies would be kicking in once they didn't have enough food and stopping them from dying, which would be actually great, starvation mode, even though it's seen as a negative thing, if it did exist, it would probably be really helpful. That's not actually the case, though. What starvation mode probably is, is a misrepresentation of some things that do occur. There are things that do make it more difficult to lose body fat as we progress, there are things getting in the way. It's not your body stopping you from losing body fat, you don't reach a point where it's not possible. You can reach a point where it's probably not a good idea to continue, we can talk about that in a second, but you're always going to be able to outrun these adaptations that we'll talk about in a little bit. So first off, there's a couple of very non-sciencey explanations as to why you might feel you're in starvation mode, or why someone might be describing themselves as being in starvation mode. The first very simple one, don't hate me, stay with me, is that you might be eating more than you think you are, and that is really, really, really easy to do, particularly in this day and age, the food environment that we're surrounded in, calories can get hidden very, very easily. You look at a food on your plate, the size of that food, the shape, the color, even the taste, these things don't necessarily represent the amount of calories that are in there. I don't know if you've ever had that experience of looking at the back of a packet of something and going, holy, I didn't realize there was so much X, sugar, fat, calories, whatever, in there. Not good or bad things, but of course if we're consuming a lot of these foods and not realizing that actually they contain, for arguments sake, 30% more calories than we expected, that's going to add up. It's also so really, really easy to miss some calories that we consume during the week. You might be forgetting about the milk or the sugar in your coffee, you might be forgetting about the juice, you might be forgetting about the kids' meals that you're finishing off, you might be forgetting about the sauces or the dressings that you're using, or the cooking oils, all of these things that contain calories. And now, again, I'm not saying that any of those things are bad things, it's just, kind of like with a financial budget, if you've got a whole bunch of expenses that you don't realize that you have, if you're subscribed to a whole bunch of Netflix, Binge, where are we up to? Stan, Kayo, and you've forgotten that you didn't cancel the free trial for three of those and you've been stung $15 each per month, all of a sudden you look at your bank account and you've got a bit less money than you thought, it's the exact same thing, we can very easily exceed the amount of calories we believe we're having, even if we're tracking. If you've tracked 1500 calories into ‎MyFitnessPal, but you haven't tracked all of those things I talked about before, you're tracking 1500 calories, but you might be consuming closer to 2000 calories. Another really common mistake is that you're focusing on your day to day calories and you're just neglecting or forgetting about your weekly average. So maybe five to six days of the week you're nailing that calorie deficit, you're nailing whatever that number is for you, and you're forgetting about that one day, or the two days a week, and that's blowing your complete weekly average out. So for four to five to six days of the week you feel like you are in a deficit, you feel like you're dieting, because you are, but unfortunately that one day is wiping out any deficit that you have accrued across that week. Another really big one I find is people aren't as active as they think they are. So we focus a lot more on how often we get to the gym, and how hard we go in those gym sessions as to how active you are and how much you should be able to eat. And don't get me wrong, exercise is fantastic, it's great to be active as often as you can, but unfortunately what contributes far more to the calories that you burn is what you do for the rest of the hours, the rest of your waking hours. So if you are like me and you go and you train, and then you sit on your butt all day at work, you're not going to be burning a ton of calories, compared to if someone of my size, shape, age, gender, body composition, was a waitress, or in retail, or was a laborer doing something very physical or on their feet all day, they would be burning a lot of extra calories. And so you might feel like I can eat a lot more because I train four to five times a week, but if you're fairly sedentary outside of that, you probably don't need quite as much as you think. Those are some of the things I often see getting in the way, and they can be what's causing that difficulty to lose that extra weight. It's not starvation mode, it's lots of things that we maybe haven't stopped to consider. Now, your body does fight back to an extent. So this is really where the kernel of truth from starvation mode comes in, it's this concept called metabolic adaptation, and it is, to a certain extent, your body adapting to try and help keep you alive during prolonged periods of not enough food. We can outrun all of these things though, and I'll talk about that in a second, but essentially what your body does to adapt, to reduce the calories that you burn, is it does a couple of different things. First off, it can lower your body temperature, makes you a little bit colder, you burn a few less calories. It can cause you to subconsciously reduce your activity levels. So if you are sitting in your bedroom and you forgot your water bottle, its sitting out on the kitchen bench, and you have been dieting, you've been on pretty low calories, you might be thinking that I don't really need that water bottle, I'll get it later. And you don't even think through all of that, it's just something that just happens, you do a few less steps, you gesture less. People that have dieted for a long time blink slower, all of these things cause you to burn less calories. Your hunger hormones also get out of whack, your body will be increasing the amount of ghrelin, or rather should I say the amount of leptin that you have, which is a hormone that signals to your body, hey, I'm full. Leptin is released by fat cells, so the more fat cells you have, the more leptin you have, theoretically the more of a signal saying I'm full you have. If you have lost some body fat, you've started to lose some body fat and you've plateaued and you're struggling, that initial loss of body fat is going to have resulted in less leptin circulating around, less of that signal saying I'm full. This means that ghrelin, which is the equal and opposite version of leptin, gets to exert its actions a lot more strongly. Ghrelin makes your stomach growl, ghrelin makes you hungry, so you're dealing with this subconsciously increased level of hunger, which is probably going to be leading to you over consuming foods more often, because you're hungry, and you're a human being. Another thing that your body does, and this can be a really big one, is it starts to reduce the amount of energy that it sends to your non-essential systems in your body. So if your heart or your brain, and to a slightly lesser extent your liver and your kidneys and things, if they don't get the energy that they need, you probably are going to die. That's a pretty serious situation to be in, so your body prioritizes those systems. Now, if all of my fingernails fall out tomorrow, or if all of my hair falls out tomorrow, I'll be pissed, but I'll be alive, so those systems, our hair, our skin, our nails, our reproductive system is another really big one, if our body believes that there's not enough food around, the last thing it's going to want me to do is bring another mouth to feed into this world, so it starts to pull energy away for those systems. And so to use incredibly arbitrary numbers, let's say that for me to maintain, and to run all of my cardiovascular system, my respiratory system, my gastrointestinal system, my skin, my nails, my hair, my reproductive system, my immune system, to run all of those things at peak performance I need two and a half thousand calorie calories. But because I've been dieting, my body spends less energy on my reproductive system, and less energy on my hair, skin, and nails, and so I actually only need 2000 calories to maintain. And so if I was eating two and a half thousand calories and I've decided I'm going to cut my calories to 2000 calories, I'm still not in a deficit. Now I might be thinking, oh, but I've cut 500 calories, why am I not losing weight? It must be because of starvation mode, it's actually not. It's because of those things that your body, those small adaptations your body has made. So now if I had dropped my calories to 1700 calories, the weight would start to come off it again. How we can deal with metabolic adaptation, how we can work around that, it's not as simple as just drop your calories as low as humanly possible, but in the interest of keeping these podcasts nice and short, that might be a topic for another time. But hopefully I've explained why the concept of starvation mode, fat loss grinding to an absolute halt and there being nothing you can do about it, is a flawed concept. It's not an actual mode that your body gets into, there are factors to consider, both biologically and also behaviorally. But the underlying message is you can work around these, you don't reach a point where you're screwed because you're in starvation mode. Thanks to listening guys. As always, if you liked it, feel free to share it with a friend. If you've heard someone use the phrase starvation mode, send it to them with love. The goal of this is not to judge people who've used the phrase starvation mode, I certainly have in the past, we probably all have. But instead knowledge is power, we want to learn what the actual science is saying so we know what to do in the meantime. I will catch you next time.