How to Lose Fat With Science-Based Tools

The episode opens with Andrew Huberman introducing himself as a professor of neurobiology and ophthalmology at Stanford School of Medicine. He describes this as the third episode in a series on physical and athletic performance and skill learning, with this one devoted to the science of tools for fat loss. The case for the topic is that many people, including athletes, want or need to lose fat, that body fat percentages that are too high are unhealthy, and that most people struggle to lose body fat, or adipose tissue, in particular.

The host acknowledges that fat loss is a heavily contested subject online, and he promises tools that he expects most listeners have not heard of. The list includes cold exposure, brown fat, beige fat, something called NEAT, and a range of fat-loss processes governed by the nervous system. He calls the nervous system an important gap in the usual discussion.

He places the episode next to earlier ones on hormones, metabolism, and food and mood. Hormones such as insulin and leptin get only brief mention here. The main focus is how neurons, and cells they collaborate with such as glia and macrophages, can encourage accelerated fat loss. The underlying claim is that the nervous system, meaning the brain, spinal cord and their connections to the body's organs, "governs everything" and works as an on and off switch for the immune system and also for fat burning.

Before making claims about the nervous system, the host concedes the core rule of metabolic science. In his words:

calories in versus calories out, meaning how many calories you ingest versus how many calories you burn, is the fundamental and most important formula in this business of fat loss and weight management in general.

He says that eating far more calories than you burn is likely to cause weight gain, much of it as adipose tissue. Eating fewer calories than you burn leads to weight loss, a significant portion of it from body fat. How much of that loss is fat depends on a number of factors. He adds a complication to the slogan "a calorie is a calorie" by citing Robert Lustig, a pediatric endocrinologist at UC San Francisco. Lustig has argued that highly processed foods change how food is used and can lead to higher rates of obesity and other metabolic syndromes. The host's resolution is that a calorie remains a unit of energy and that the formula must be accepted.

His argument is that the calories-burned side is strongly influenced by factors a person can control. He lists hormones, the "thermogenic milieu" (how warm or cold the body is and how warm or cold a person makes it), level of metabolism, thyroid hormone levels, and the amount of innervation of fat by the nervous system, which he says is rarely discussed but well supported in the literature. He states that several kinds of body fat are innervated by neurons, and that these neurons can change the probability that the fat is burned. On this basis he calls the nervous system the master controller of the calories-out component.

The host promises to keep the biochemistry of lipolysis and fat oxidation brief, reducing the process to two steps. He says he will mostly discuss behavioral tools, and will also cover compounds and supplements. He presents supplements as optional and says that, for people who use them, quality and accuracy of contents matter.

Here he discloses a partnership with the supplement company Thorne. He states that the company has the highest stringency on compound quality and amounts, that it has partnered with the Mayo Clinic and major sports teams, and that listeners can see the supplements he takes and get 20% off through a dedicated link. He repeats that he is not encouraging supplement use for anyone who isn't interested. This is a commercial relationship, and readers should weigh the quality claims in that light.

Before the new material, the host summarizes foundations from earlier episodes. His reasoning is that without a sound base of health, hormones and metabolism, it is hard to get the most from any exercise or fat-loss protocol. He says nobody, himself included, follows these perfectly. He lists the items:

Sleep: get quality, sufficient sleep. Use light exposure, temperature and timing matched to one's chronotype. Avoid bright light in the eyes when you want to be asleep, and get bright light in the eyes when you want to be awake. Essential fatty acids: described as vital and obtainable from food, with supplements optional. The specific target is taking in more than 1000 milligrams of EPA per day, which may require more than 1000 milligrams of total fish oil, krill oil or another source. Food sources named are fatty fish, grass-raised meats and plant sources. He says research links this level to mood, metabolism, cardiovascular blood markers and readiness for fat loss. Glutamine for sugar cravings: he says gut neurons seek essential fatty acids and amino acids but also respond to sugars, so supplying what they "actually want" can satisfy cravings. He mentions a teaspoon or even a tablespoon a few times a day, with the caution to ease in because too much can cause GI distress. He says glutamine has also been shown to improve symptoms of leaky gut, and he names cottage cheese as a food high in glutamine. Iodine and selenium for thyroid function: he warns that iodine can be overdone. He notes that table salt often contains iodine and that some people add sources such as kelp. For selenium he names Brazil nuts, one to three a day, as the most concentrated food source he knows of, and he cautions against selenium levels that are too high. Gut microbiome: probiotics are optional. He suggests a serving or two a day of fermented foods such as sauerkraut or kimchi.

He compresses the list into "Sleep, EPA, glutamine, fermented foods, iodine, selenium" and presents it as the base on which exercise, cold and compounds can increase the burn side of the equation. These recommendations are presented as summaries of earlier episodes. This section does not detail specific studies behind them.

As a counterweight to strict energy accounting, the host describes a study by his Stanford colleague Alia Crum, a professor in the psychology department, on how belief can shape the effects of exercise on weight loss. Hotel service workers who cleaned rooms and changed linens were split into two groups. One group was told mainly that their daily job activities met U.S. guidelines for activity. The other group received more information about how movement and their daily routine were good for cardiovascular health and could help weight loss. Both groups were tracked over many weeks.

He reports that the more informed group showed significantly more body-fat loss, favorable changes in waist-to-hip ratio and other positive effects such as better cardiovascular health. He interprets this as evidence of how the nervous system and belief can govern physiology that might seem outside conscious control. He also raises the obvious confound himself: the informed group may simply have moved more or acted differently, and he calls that a strong possibility. His conclusion is that knowledge shifted both behavior and physiology, so how people think about an activity changes how they perform it, and that in turn changes physiology.

He then restates the energy-balance rule with its own hedges. Eating more than you burn typically leads to weight gain, "although not always". Eating about as much as you burn typically maintains weight. Eating less typically leads to weight loss. He asserts that belief effects have "been replicated again and again", but no further studies are named here. He places the episode's protocols between these two poles, hard metabolic science and belief effects, and describes them as grounded in peer-reviewed science.