About this Video

• Video Title: Lose Fat With Science-Based Tools | Huberman Lab Essentials
• Channel: Huberman Lab
• Speakers: Andrew Huberman
• Duration: 00:33:36

Introduction

This Huberman Lab Essentials podcast episode focuses on science-based tools for fat loss. The main topic explores the nervous system's often-overlooked role in fat burning, emphasizing the importance of calories in versus calories out while detailing methods to accelerate the "calories out" component.

Key Takeaways

• Calories In vs. Calories Out: The fundamental principle of weight management remains how many calories are consumed versus burned.
• Nervous System's Role: The nervous system, through the release of epinephrine (adrenaline) from neurons connected to fat cells, plays a crucial role in fat mobilization and oxidation.
• Increasing Adrenaline for Fat Loss: Movement, especially subtle movements (fidgeting) and shivering (induced by cold exposure), stimulates epinephrine release and accelerates fat burning.
• Cold Exposure Protocol: Deliberate cold exposure, involving cycles of cold immersion and breaks (without drying off), activates brown fat and increases metabolism through succinate release.
• Exercise for Fat Loss: High-intensity interval training (HIIT) followed by low-intensity exercise, ideally fasted, maximizes fat burning. The 90-minute threshold for fasted exercise applies primarily to moderate-intensity continuous training (MICT).
• Compounds to Boost Fat Loss: Caffeine (100-400mg before exercise), yerba mate (increases GLP-1), and pharmaceuticals like semaglutide (prescription only) can enhance fat oxidation. Berberine and metformin indirectly promote fat burning by lowering insulin levels.
• Diet Adherence: Sticking to a chosen dietary plan (regardless of type) is crucial for achieving a caloric deficit and weight loss. Low-carbohydrate diets can be advantageous for keeping insulin levels low, thereby promoting fat oxidation.

The transcript indicates that combining high-intensity training (like weightlifting or sprints) with low-intensity exercise (Zone 2 cardio) is a beneficial approach for maximizing fat burning, particularly when done in a fasted state. The advantage of a fasted state is more pronounced when starting with high-intensity exercise. For longer durations of moderate-intensity continuous training (MICT, approximately 90 minutes or more), a fasted state leads to greater fat burning than exercising after eating. However, if only high-intensity or short bursts of high-intensity exercise are performed (up to 60 minutes), the beneficial effect of a fasted state occurs sooner than the 90-minute mark for moderate-intensity exercise. The reason for this difference is that the body's shift from burning glycogen (sugar) to burning stored fat occurs earlier with high-intensity workouts, because the high intensity and effort deploy more adrenaline. The shift to fat burning during moderate-intensity exercise occurs at approximately the 90-minute mark because that is when insulin levels have dropped sufficiently and the body begins to utilize stored fat for fuel. If one eats beforehand, this shift is delayed.

Here's a verbatim excerpt from the transcript covering the discussion of high-intensity interval training (HIIT) followed by low-intensity exercise, ideally fasted, and its effect on fat burning:

"Now, there are also studies that point to the fact that you don't have to wait to 90 minutes in order to get this enhanced fat-burning effect. If one does high-intensity training or even the very high-intensity forms of training like sprints or squats or deadlifts or any kind of activity that can't be maintained for more than these eight or I would say up to 60 seconds, so a set of lifting weights repeated, repeated. If that's done for anywhere from 20 minutes, so weight training or powerlifting or these kinds of things or kettlebell swings, or up to 60 minutes, well, then the switch-over point in-which you can burn more fat if you go into that fasted comes earlier. This makes sense because there's nothing wholly about the 90 minute point for medium-intensity Zone 2 cardio. That 90 minute point is the point in which the body shifts over from mainly burning glycogen, basically sugar that comes from muscles or the liver, and realizes this is going on for a while. I'm going to shift over to a storage-site fuel that is in reserve like body fat. This is something that has to do with the milieu of various hormones. What has to happen is insulin has to go down far enough. If you ate before the exercise, you'd have an increase in insulin. If you ate carbohydrates, you'd have a bigger increase in insulin. Fat and proteins indeed will have lower amounts of insulin and fasting will give you the lowest amount of insulin. Well, then that switch-over point is going to come earlier in the exercise. If you think about it, if you were to do something high-intensity for 20, 30, 40 minutes, so maybe lift weights and then get into Zone 2 cardio, if you were fasted, the literature says that you're going to burn more body fat per unit time than if you had eaten before or during the exercise. What does this mean? This means if you want to burn more body fat, if it's in your protocols and you have been approved to do this safely, exercise intensely for 20 to 60 minutes. The higher the intensity, obviously, the shorter that bout is going to be, and then move over into Zone 2 cardio. If you do that fasted, then indeed you will burn a higher percentage of body fat. If you can't even get to the exercise, if you're somebody who just can't do the training at all, you're unwilling to or you're incapable of training unless you eat something, then obviously eating something makes the most sense. What you eat prior to exercise, that's a whole other biz that people argue about and fight about whether or not you should go into it with low carbohydrates or high carb or all of that. In general, the theme there is very simple, which is that you want insulin levels to be pretty low if your goal is body-fat reduction."