Lose Fat With Science-Based Tools | Huberman Lab Essentials
Date: 2025-04-03 | Duration: 00:33:36
Transcript
0:00 Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I’m Andrew Huberman, and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. Today, we’re going to talk about
0:30 the science of tools for fat loss. Today’s episode is mainly going to be focused on how the nervous system—neurons and some of the cells they collaborate with, like glia and macrophages—how those encourage or can encourage accelerated fat loss, because it turns out they can. Remember, your nervous system, which includes your brain and your spinal cord and all the connections that they make with the organs of the body, governs everything. The nervous system
1:00 and the role of the brain and other neurons has been vastly overlooked in the discussion about losing fat. Now, I would be remiss and I’d probably come under a pretty considerable attack if I didn’t just acknowledge upfront a core truth of metabolic science and also of neuroscience, frankly, which is that calories in versus calories out—meaning how many calories you ingest versus how many calories you burn—is the fundamental and most important formula
1:30 in this business of fat loss and weight management in general. There’s simply no way around the fact that if you ingest far more calories than you burn, you’re likely to gain weight, and a good portion of that weight is likely to be adipose tissue—fat. It’s also true that if you ingest fewer calories than you burn, you will lose weight, and a significant portion of that will come from body fat. What portion depends on a number of factors, but that simple formula is important. So, a calorie is a
2:00 calorie as a unit of energy, and we need to accept and acknowledge this calories in versus calories burned formula. But the calories burned portion is strongly influenced by a number of things that you can control that can greatly accelerate or increase the amount of adipose tissue, or the proportion of adipose tissue, that you burn in response to exercise and food.
2:30 Today, we’re going to talk about the fact that your body fat of various kinds—and there are several kinds of body fat—are actually innervated by neurons. Neurons connect to your body fat and can change the probability that that body fat will be burned or not. So, your nervous system is the master controller of this process, and it plays a strong role in the calories out, the calories burned component. So, let’s talk about fat utilization. Let’s talk about how fat is
3:00 converted into energy, which is sometimes also called fat burning. There are two parts to this process: one is fat mobilization, and the second is fat oxidation or utilization, and that’s a process called lipolysis. Fat cells can be visceral, around our viscera—our organs—or they can be subcutaneous, under our skin. Stored fat has two parts that are relevant here: it’s got the fatty acid part, and that’s the part that your
3:30 body can use, and that’s attached to something called glycerol, and they’re linked by a backbone. To mobilize fat, you’ve got to break the backbone between glycerol and these fatty acids. That’s accomplished by an enzyme called lipase, but you can forget all that if you want. Remember, we’re just trying to mobilize fat. So, the first step is to get those fatty acids moving around in the bloodstream, to get them out of those fat cells, and then they can travel and be used for energy. They’re going to go into
4:00 cells that can use them for energy, and once they are inside those cells, they’re still not burned up. You need to oxidize them; they need to be moved into the mitochondria, and then they can be converted into ATP, into energy. So, just to really zoom out again to make sure I don’t lose anybody: you’ve got to mobilize the fat, then you have to oxidize the fat. Many of the things that the nervous system can do is to increase the mobilization of fat, but also the
4:30 oxidation of fat. So, what are these neurons that connect to fat doing? What are they releasing exactly? How do they actually increase fat mobilization and how do they increase fat oxidation, the burning of fat? Well, there are a couple of things that they release that encourage that process, and the main one that you need to know about is epinephrine, or adrenaline. The conversion of these fatty acids into ATP in the mitochondria of cells is favored by
5:00 adrenaline. Adrenaline is released from two sources: adrenaline is released from the adrenal glands, which sit atop our kidneys in our lower back, and it’s also released from the so-called sympathetic nervous system, although that name is a bit of a misnomer because it has nothing to do with sympathy; it has to do with stimulating alertness and promoting action of the body. It was thought for a long time that adrenaline swimming around in your body when you’re
5:30 fasted—because fasting can increase adrenaline—or when you’re engaging in intense exercise or when you’re stressed, is going to promote fat oxidation. That’s actually not the case. The adrenaline that stimulates fat oxidation, the burning of fat, is coming from neurons that actually connect to the fat. It’s a local process, and this is very important because it means that what you do—
6:00 the specific patterns of movements and the specific environment you create that can stimulate these particular neurons to activate fat, meaning to release fat, to mobilize it, and then to burn it—is going to be a powerful lever that you can use in order to increase fat loss. So, let’s talk about how to activate the nervous system in ways that promote more liberation, movement, mobilization of fat, and more oxidation
6:30 of fat. One of the most powerful ways to stimulate epinephrine, which is also called adrenaline, from these neurons is through movement. The type of movement that I’m referring to is extremely subtle. Shivering is a strong stimulus for the release of adrenaline/epinephrine into fat and the increase in fat oxidation and mobilization. There are other subtle forms of movement that can greatly increase fat metabolism and fat loss.
7:00 There was a group in England during the 1960s and ’70s that discovered a pathway by which subtle forms of movement can greatly increase fat loss. This is the work of Rothwell and Stock; it’s very famous in the thermogenesis literature. I learned about this early on when I was an undergraduate and I asked, “How did they come across this?” Here’s how the story goes: they were aware that some
7:30 people overeat and yet don’t put on weight; other people overeat even just a little bit and they seem to accumulate extra adipose tissue. Now, this is long before all the discussions about microbiome and hormone factors; long before many of the hormone factors besides insulin had even been discovered. What they did was they examined people who overate and did not gain weight, and what they observed was
8:00 that those people engaged in lots of subtle movement throughout the day. In other words, they were fidgeters, and that’s what they called them. In 2015 and again in 2017, there have been studies that have explored this using modern metabolic tracking, and indeed, simply moving a lot—being a fidgeter, bouncing your knee, standing up and pacing several times or many times throughout the day—led to considerable amounts of fat loss
8:30 and weight loss when people were ingesting the same amount of food. If they overate, they were able to compensate and burn off that food. So, for people that are overweight who are averse to exercise, fidgeting might actually be a good entry point. Now, that’s great, and you can think about the protocols, but I want to nest that protocol in what I said before, which is that fat is controlled by these neurons
9:00 and the epinephrine they release. Those subtle movements of our core musculature—not just the core, but all our limbs and our musculature—those low-level movements trigger epinephrine release from these neurons and they stimulate the mobilization of fat, and then that fat is oxidized at higher rates. So, what’s the protocol? Fidget. If you’re really interested in burning calories and you already exercise, you want to burn more, or you
9:30 don’t have the opportunity to exercise, or you’re averse to exercise for whatever reason, fidgeting movements—staccato movement, standing up, walking around, pacing—all the sort of nervous activities that we’re so critical of in other people and sometimes in ourselves are actually mobilizing and oxidizing a lot of fat and a lot of energy. While this probably won’t compensate for chronic overeating, the caloric burn from this is considerable and very likely can offset a meal that had excessive calories or a steady state of eating too much.
10:00 Now, it should make sense why shivering is one of the strongest stimuli that one can incorporate to stimulate fat loss. Now, shivering is almost always associated with cold. We think shivering, we think cold, because when we get cold, we shiver. There are two ways that shivering
10:30 can increase fat loss, and there are several ways that you can use shivering. You can leverage shivering and you can leverage cold to accelerate fat loss, but you have to do it correctly. Most of the people that are using cold and, frankly, suggesting cold as a means to increase metabolism and fat loss are suggesting the exact wrong protocol. Most people out there are using cold exposure typically by taking cold
11:00 showers or by getting into cold water of some other kind—a lake or a river or a cold bath or an ice bath. Since today we’re talking about accelerating fat loss through the use of science-based tools, I want to emphasize a study that was published in Nature just a couple years ago showing exactly how cold increases metabolism and fat loss. We have several kinds of fat—three kinds, in fact. We have white fat (white adipose tissue),
11:30 we have brown fat (brown adipose tissue), and there’s a third kind, which is beige adipose tissue. White fat is the type that we traditionally think of as fat—subcutaneous fat—and it is not particularly rich in mitochondria. It is there as an energy storage site, and we have to mobilize the fat out, as we talked about before, and burn it up elsewhere. Brown fat largely exists
12:00 between our shoulder blades and on the back of our neck, between the scapula, and it’s rich with mitochondria, which is why it’s called brown fat. Brown fat has a particular biochemical cascade whereby it can take food energy and basically break it down and convert it into energy within those cells. But unlike fatty acids from white fat, which have to travel elsewhere, get
12:30 broken down in mitochondria, and converted into ATP, etc., used by the mitochondria, brown fat is thermogenic; it can actually use energy directly. Cold causes the release of adrenaline from your adrenals and it causes the release of epinephrine from these neurons that connect to fat. The paper published in Nature shows that it is shivering itself that causes the brown fat to
13:00 increase your burn rate and your metabolism. It works like this: when you get into cold and you shiver, that low-level movement of the muscle—those small movements—triggers the release of a molecule called succinate. Succinate acts on