The term metabolism is often included in discussions relating to weight and fat loss and naturally so, but do we really know what our metabolism fully is and how it works? Is there such a thing as having a slow metabolism?
Recently I had the privilege of listening to Dr. William Li, internationally renowned medical doctor, researcher, president and a founder of the Angiogenesis Foundation and author, discuss some of the latest, fresh off the presses research on metabolism and body fat and was amazed at what I learned.
In his latest book, Eat To Beat Your Diet, Dr. Li shares a wealth of information on how to burn body fat, eat to support your metabolism and stave off chronic diseases as a result. Some of the key highlights that I came away with from listening to an interview Dr. Mark Hyman conducted with Dr Li were so impactful and eye opening to me that I now have a newfound perspective on human metabolism and the function of body fat. In this blog I’m going to highlight what I learned about the 4 stages of metabolism, foods that feed our brown fat and body fat as an endocrine organ.
The Four Stages Of Metabolism
In his interview with Dr. Hyman, Dr. Li shared that a cutting edge research study conducted in 2021 revealed that there are 4 stages of metabolism for all human beings. This study included 90 researchers from 20 countries and included 6,000 subjects, ranging from age 0-90. I was shocked to learn the following:
• Stage 1: Age 0-1 years. During this phase of life the human metabolism skyrockets to a rate that is 50% higher than it will be in later stages of life as an adult. This was no huge surprise.
• Stage 2: Age 1-20 years. During these 2 decades of early life our metabolism gradually decreases. I was amazed and shocked to hear this. We all think that during our adolescence and teenage years our metabolism is cranked up and surging, but according to this study's results, it’s not the case. It’s not to say that our metabolism isn’t at a high functioning level, but it’s on the decline through this life phase.
• Stage 3: Age 20-60 years. The most dramatic revelation this study revealed is that in this stage of life, our metabolism stays relatively the same! Are you surprised too?
• Stage 4: Age 60-90 years. And lastly, human metabolism only declines by 17% during this phase of life.
What a revelation it was for me to learn about these stages of human metabolism. The majority of the human population doesn’t experience what this study revealed. So if our metabolism is much more stable through life than we thought, what are the main drivers of increased body fat as we age? Of course Dr. Li answered that burning question.
The primary causes of increased body fat are lifestyle habits, changes in our microbiome, lack of exercise, increased stress and poor sleep. But beyond these factors, he went on to mention something that does slow down metabolism; high levels of body fat. The more body fat we accumulate, the slower our metabolism becomes. Using a computer as an analogy, he explained the impact body fat has on our metabolism by describing that in essence, excess body fat causes our metabolic system to become glitchy like our computers when they need an operating system clean up. When our body fat cells (adipocytes) expand beyond their natural capacity, just like a gas tank that is overflowing, body fat will spill out into other areas of our body (more fat cells are produced to hold the excess energy) and wreak havoc of various sorts, i.e. mucking up our operating system.
Why Do We Have Body Fat in the first place and is all of it harmful?
Absolutely not! And here are 5 major functions body fat performs in the human body:
1. Protects Vital Organs: It acts as a cushion to protect the body's internal organs from injury.
2. Energy: It functions as an efficient form of energy storage that the body can use on an as needed basis by converting the food we eat into fuel.
3. Vitamin absorption: Certain vitamins, such as vitamins A, D, E, and K, are fat-soluble, meaning they require fat to be absorbed and utilized by the body. Body fat serves as a reservoir for these vitamins.
4. Hormone regulation: Adipose tissue (body fat) is actually the largest endocrine organ in the body. It produces up to 15 different hormones that regulate appetite, metabolism, and immune function. Some of the hormones produced by adipose tissue include:
Leptin: known as the satiety hormone, but in general it regulates appetite and metabolism by signaling to the brain when the body has enough energy stored as fat. It also plays a role in fertility and bone metabolism.
Adiponectin: a hormone that regulates insulin sensitivity and glucose metabolism, which can help prevent or reduce the risk of developing type 2 diabetes.
Resistin: found to play a role in regulating glucose metabolism and insulin sensitivity.
TNF-alpha: This signaling molecule contributes to inflammation and insulin resistance.
These are just a few of the hormones and signaling molecules produced by adipose tissue that can have both local and systemic effects on the body, impacting processes such as energy balance, glucose and lipid metabolism, immune function, and inflammation. Excess body fat however can lead to dysregulation of these hormones, contributing to the development of metabolic disorders such as obesity, type 2 diabetes, and cardiovascular disease.
5. Fuel Tank for Brown Fat: We have 2 types of adipose tissue; white and brown. Brown adipose tissue (BAT), which is abundant in babies and hibernating animals, plays a major role in thermogenesis (heat production) and calorie burning. As adults we have smaller amounts of brown fat, but its role in the body continues to be vital.
Adipose tissue can fuel brown fat through a process called lipolysis. Lipolysis is the breakdown of stored fats (triglycerides) in adipose tissue into fatty acids and glycerol, which can then be used as an energy source by various tissues in the body, including brown fat.
When activated, brown fat cells take up fatty acids from the bloodstream and use them to generate heat - thermogenesis. Unlike white adipose tissue, brown fat is full of mitochondria, the energy organelles of the body, which are rich in iron, thus giving brown fat its color.
Foods that Turn On Brown Fat & Burn Body Fat
In the last decade or so, research around the benefits of brown fat and how to stimulate it in the adult body has expanded. In the late 2,000’s when the scientific community was beginning to buzz around the discovery of brown fat in adults, it was soon found that exposing people to cold temperatures stimulated BAT. But cold exposure isn’t an easy sell for many, so more research on how to stimulate brown fat continued.
In Dr. Li ‘s interview, he revealed that recent research has identified certain foods that stimulate brown fat. Some of the foods that Dr. Li mentioned as potential brown fat stimulators include:
Resveratrol-rich foods: Resveratrol is a compound found in red grapes, blueberries, peanuts, and dark chocolate, and has been shown to increase the activity of brown fat.
Foods high in flavonoids: Flavonoids are antioxidants found in many fruits and vegetables, such as citrus fruits, apples, and onions. They have been found to increase brown fat activity in animal studies.
Foods rich in capsaicin: Capsaicin is a compound found in various types of chili peppers and has been shown to increase brown fat activity and boost metabolism.
Green tea: Green tea contains catechins, which have been found to increase brown fat activity and help with weight management.
Omega-3 fatty acids: Omega-3s which are high in the SMASH fish - salmon, mackerel, anchovies, sardines and herring as well as in walnuts and flaxseeds, have been shown to increase brown fat activity and improve insulin sensitivity.
Sulforaphane Rich Foods: sulforaphane is a plant compound found in cruciferous vegetables such as Brussels sprouts, broccoli, cauliflower, kale, Swiss chard and Bok Choy. It’s known for its antioxidant, anti-inflammatory and antimicrobial properties. And now the stimulation of brown fat can be added to their list of health benefits.
The revelatory information that I came away from after listening to Dr. Li’s interview reinforced how important it is for us to focus on eating whole, organic, unprocessed foods primarily and to manage our weight for optimal health and longevity. And to reiterate, body fat is not BAD. It’s essential for life and health. However, excess body fat is a form of inflammation and when fat cells get overly full, the excess fatty acids leak out causing toxicity to the liver, which can lead to NAFLD (non alcoholic fatty liver disease), diabetes and cancer.
If you’re seeking customized support to optimize your nutrition and weight management pursuits, feel free to reach out. I’m here to help: Lisa@livingproofnyc.com