Entrepreneur: Hello, Wales. Have you ever looked in the mirror and thought to yourself, I wish it was a little bit taller? I wish it was a baller? Well, wish no longer my friends. Imagine— a product that can give anybody, ANY BODY they want at the snap of a finger. Introducing the BD 5001, by my company Built Different Enterprises. Tina: So like "Build a Badger"? Entrepreneur: Sort of. You can build it, rebuild it, buy it, break it, use it, fix it, trash it, change it. Anything you want! Tina: This is ridiculous. Whale 1: Yeah, you can't just change your body like that. The way your built is the way you're built. It's all genetics. Tina: Well.. Entrepreneur: Are you an endomorph but want to be an ectomorph? Are you a mesomorph, but want to be a mighty morph? With the BD 5001, you can be built different. Tina: Okay, so we know that people's bodies are different. We come in all shapes and sizes. But why is that? Is it because of differences in our DNA? Or is it because of differences in our behavior and environment? Or could it be both? The answer is that most traits exist on a spectrum. On the one end, there are traits that are very easy to change because they're incredibly responsive to environmental and behavioral changes. On the other end, there are traits that are constant throughout our lives and strongly determined by our genes. Somewhere in the middle. There are traits that become fixed at some point in our lives, but can be influenced by environmental and behavioral factors early in development. So, how easy is it to change our bodies? Well, the answer is, it depends on what you're trying to change. Entrepreneur: Let's say this week, you want to be an Olympic sprinter. And next week, you want to be a marathon runner. With the BD 5001 has you covered. Whale 2: Sounds good to me! Hey, if you can put your mind to it, you can put your muscle to it. Build-a-body. Now that's an idea I can invest it. Whale 1: You can't just build a body. Everyone has limitations. Yeah, there's people that can be sprinters and marathon runners. But what about the people that can't do anything at all? You can't just change these things. Tina: Okay, when it comes to muscle, there is some truth to the fact that different people have different limitations. But to say that we can't change at all isn't really accurate. While we all have muscles, how much muscle we have and how strong they are, differs from person to person. This is the result of a complex interaction between our genes and our behavior. We usually talk about three different muscle types: cardiac muscle, smooth muscle, and skeletal muscle. We'll be focusing on that last type since it's the one we can voluntarily control. But did you know that there isn't just one type of skeletal muscle? There are two: slow-twitch (type one) and fast-twitch (type two). Fast-twitch muscles are used in explosive movements and slow-twitch muscles help with activities that require endurance. But we actually all have both kinds. It's just that we have them in different proportions. The proportion of fast to slow twitch muscles is strongly influenced by our genes. For example, certain mutations in the AGTR2 gene, which is involved in skeletal muscle development, result in people having significantly higher percentages of fast-twitch muscles. Another gene, the ACE has variants associated with an increase in slow-twitch muscles. However, it's not just about our genes. Our behavior influences what we can do. So don't assume you can win the 100 meter dash just because you have a high proportion of fast-twitch muscles. You're still going to have to show up to track practice if you're really about that life. But overall, when it comes to muscle, it's true that you can change your body. You can grow your muscles and you can train them to get better at specific kinds of movement. If you want to run marathons, you'll be engaging those slow-twitch muscles. If you want to do high intensity things like sprinting, you'll be firing up those fast-twitch muscles. You can train to do both things. Although, switching it up on a weekly basis might be a little bit intense for us nonathletic regular people. Entrepreneur: Look, our tech doesn't just make you buff. Sometimes you want a little junk in your trunk. You want that thang to be thang-in'. You know what I'm saying? Whale 2: Ha Ha! Yeahhehe Whale 1: No. Entrepreneur: Trying to fill in those jeans a little bit better? The BD 5001 has you covered. Not enough cheeks for grandma to pinch? We can fix that too. You know the vibes! Tina: Okay, we know the vibes, but how about we get the facts. What we call fat is also known as adipose tissue, which is a loosely joined tissue made mostly of adipocytes. The primary job of adipocytes is to store energy. Biologically, adipose tissue is an essential part of our energy storage system and plays a key role in protecting our organs, absorbing nutrients, and producing important hormones. But did you know there are actually two different types of fat? The kind that we most often think of is white adipose tissue, but there's also a brown adipose tissue. Entrepreneur: Listen, right now we have a special sale going on where you can upgrade your fat to premium Brown addition. It has a heating function to keep you warm during those frosty winter nights. Tina: White adipose tissue is responsible for storing energy in the form of triglycerides. While brown adipose tissue burns energy to generate heat. Hormones play a role in regulating how much white versus brown adipose tissue you have in your body. Evolutionarily, brown adipose tissue helped humans thrive in cold environments. Even today, reindeer herders in the Arctic have been shown to have relatively high proportions of adipose tissue, especially brown adipose tissue, to help keep them warm. So how easy is it to control when and where we gain fat? Unlike muscle, there isn't a particular movement you can do to promote the accumulation and loss of fat in a particular area of the body. Hormones play a major role in regulating fat cells. And those hormones can indeed be linked to particular behaviors or environmental factors. In terms of fat distribution, sex hormones and sex hormone receptors play a big role. Sex hormone receptors are proteins that are found on the surface of cells. These receptors are responsible for receiving signal molecules (hormones) and transmitting them into the cell. There are two main types of sex hormone receptors: estrogen receptors and androgen receptors. These two receptor types interact differently with how our bodies distribute our fat. People with more estrogen and estrogen receptors typically have more of their fat stored as subcutaneous adipose tissue. Meanwhile, people with less estrogen often have more visceral adipose tissue. If estrogen levels go down, such as during menopause, the proportion of subcutaneous adipose tissue can drop, while the proportion of visceral adipose tissue increases. In terms of interventions, we can see certain correlations with overall hormone and hormone receptor levels when it comes to subcutaneous versus visceral adipose tissue. And of course, depending on our calorie intake, we can make it easier or harder for our body to increase the amount of fat that we have. However, if you want it to spot reduce or increase the amount of adipose tissue in specific areas of your body, these results unfortunately can't be produced without surgical intervention. Whale 1: Okay, let's talk financials. How much have you spent on this? Entrepreneur: So far I've spent $15,000. And it's also cost me my wife, my two kids, and feathers my goldfish. Whale 2: I think you have a good plan. Do you know what people will really pay for? Changing their height. Tina: Once you're done growing, there's nothing short of surgery that's going to make your bones longer. But why is that? What is height and why does it stop at a particular age? Height is determined primarily by the length of our bones. Bone growth happens most rapidly during childhood and adolescence. As we reach adulthood, our bones begin to fuse together and growth slows down. Eventually, it stops altogether. The two main types of hormones that affect bone growth are pituitary gland hormones and sex hormones. Pituitary gland hormones are responsible for stimulating growth plates, which are areas of cartilage near the ends of long bones, where new bone cells are produced. This process is called ossification. sex hormones such as testosterone and estrogen also play a role in ossification. They help determine the rate at which bones mature. So before we're done growing, what factors affect how much we will grow? One big factor is nutrition. Since height is a question of bones, you need materials, aka nutrition to build those bones. And in terms of that nutrition, there are critical windows when this appears to have the biggest effect on our final height. The first growth period occurs between conception and the age of two. This is a very important period because it's when our nutritional requirements are at their highest relative to our body size. The second period is sometimes called a catch-up period. It occurs just before puberty. If we don't get enough nutrition during the first growth period, our body will sometimes delay puberty, giving us more time to grow and prepare for a final growth spurt; meaning that we might still reach our maximum height potential. But thinking of our final adult height, assuming we gotten all the right nutrients at all the right times to reach our maximum height, there would still be variation. That variation has to do genetic differences. Those genetic differences don't directly dictate height, but rather the influence all the intermediaries that affect bone growth, including the length of your growth periods, their timing and the rate of your growth. Even though there are a lot of genetic factors influencing height, those factors interact with environmental signals, like nutrition and stress, in complex ways. So, the verdict. Of all the traits we've discussed, this one is the least changeable. Even during childhood, it's hard to reliably influence our final height. Whale 1: Look, I have some concerns. We are socially responsible whales that take antiracism seriously. How do we make sure that we're making a product for everyone? Those that are thick with three C's or those that are skinny minis? Whale 2: And what about people who leave the house in a winter time with shorts on? Whale 1: We can ignore differences in people. This is not a good strategy for equity. Entrepreneur: You know, based on my team's research, everybody's built different. But those differences aren't based on race. Tina: So we know that there are differences between people. But how are those differences distributed? Is it true that certain races have certain bodies? Well, when we talk about race, we're usually referring to continental level groupings of people. And if you look at the global distribution of human biological variation, traits vary within continents. And there are traits that are present across continents. Across Europe, Asia and Africa, we can find groups of individuals with short and tall stature. So that's height, but what about adipose tissue? Because this trait is so plastic, it's very hard to tease apart how much of the variation between groups is related to non genetic factors versus genetic factors. So in this case, when you see differences, it's important to pause and think about the extent to which they might be driven by behavior and environment. We touched on fast-twitch and slow-twitch muscles and now is a good opportunity to dispel the myth that certain races are better at particular sports. Why some nations are overrepresented in certain categories of sports has less to do with natural inclination or physical build, and more to do with socio political history that lead some communities to participate in certain sports at higher rates. If we think about strength and explosive power (fast-twitch muscle based), this can be represented in sprinting, where Jamaicans have frequently won Olympic medals. But fast-twitch muscles are also important for strongman competitions, where Iceland is very well represented. Conversely, marathons see a lot of representation from Kenya and Ethiopia, while Italy and Germany are frequently represented in cycling competitions. But both these sports engage slow-twitch endurance muscles. Also, for each of these athletes to perform at their highest level, they have to train for years. No way around it. So while there are differences between individuals in terms of how they're built, this is a result of a complex interaction between environments and genes. And on the level of genetic variation, that variation is not neatly divided among continental populations. Put another way, two populations could be distantly related and physically similar. Conversely, another pair of populations could be more closely related, but built different. Whale 1: Y'all, I'm done imagining. You're doing too much. I'm backing out of the scam. Whale 2: No, he's not doing enough! Look, I was rooting for you, but you don't have enough vision. For that reason, I'm out as well. Tina: You know what? I think this guy is doing just enough. Clearly, you have some science to iron out. But I see the innovation here and I'm ready to step in and imagine with you. So what do you say, take me on as a science consultant and I'll offer you $600,000 for 10% of the company. Entrepreneur: Thank you *scheming laughter* Whale 2: Here's the thing. I forgot my line. Alright, here we go. Whale 1: Scene One. Shot Delta. Take two. Us as whales are socially responsible people that care about or take... *team laughing hysterically*