Nutrition advice is everywhere, but clarity is harder to find. Between headlines, trends, and conflicting opinions, it is not always clear what actually matters for long-term health.
That is why we have partnered with Dr. Joey Muñoz, PhD, to break down the science behind body composition, muscle, and longevity, starting with the foundations. In this three-part, evidence-based series, we explore:
- Why muscle plays a critical role in long-term health and aging
- How different types of body fat influence metabolism and inflammation
- Why the number on the scale does not tell the full story, and what to focus on instead
Each article is designed to help you better understand what is happening inside your body, so you can make more confident, informed decisions about your health.
Recap From Part 1
Welcome back to our three-part series on the science of body composition, muscle, and longevity. Missed the first newsletter? Check it out here.
Let me quickly reintroduce myself. I’m a Nutrition Science PhD, founder of Fit4Life Academy, and host of the Dr. Joey Munoz Podcast. I’m partnering with Cronometer to bring you this three-part series on the science of body composition, muscle, and longevity.
Understanding the Role of Fat in Health
Most people think of fat as something that simply sits on the body, a passive storage of extra calories. But fat is far more than that. It’s an active, complex organ that communicates with the rest of your body every single day.
In today’s email, we’ll explore how different types of fat affect your health, why visceral fat is especially harmful, and how excess fat drives chronic inflammation that impacts nearly every system in your body.
Rethinking what Fat Really is
When most people hear the word fat, they think of body fat, the stuff they’re trying to lose. But here’s the twist. Fat isn’t just sitting there waiting to be burned off. It’s alive. It talks. It sends signals all over your body, to your brain, your muscles, even your immune system. And depending on where that fat is stored, those signals can be helpful or harmful. Some types of fat actually protect your organs and help regulate your hormones. Others quietly push your body toward inflammation, insulin resistance, and fatigue.
So this isn’t really a story about how much fat you have. It’s about what your fat is doing behind the scenes. And once you understand that, it completely changes how you think about health, metabolism, and even training results.
Subcutaneous vs. Visceral fat
There are two main types of body fat, and they behave very differently.
Subcutaneous fat
Is the kind you can grab with your hands. It sits just beneath your skin and makes up most of the visible fat on your body. You might see it around your belly, thighs, or arms. In moderate amounts, it’s not dangerous. In fact, it provides insulation and protection for your body. The main issue with subcutaneous fat is aesthetic, not metabolic.
Visceral fat
On the other hand, is a completely different story. You can’t see it, and you can’t grab it. It lives deeper, surrounding your liver, pancreas, and intestines. Imagine it like a thick layer of padding wrapped around your organs, silently affecting how they work every single day.
Here’s Why it Matters
Visceral fat is metabolically active, meaning it doesn’t just sit there. It releases inflammatory chemicals, disrupts how your body handles sugar and fat, and makes your organs work harder than they should. Over time, that constant stress can lead to insulin resistance, high blood pressure, and even changes in how your brain regulates hunger and energy.
The tricky part is that you can have a normal body weight and still carry a high amount of visceral fat. That’s why someone who looks fit on the outside might still struggle with energy, recovery, or health issues. Their internal environment is inflamed and overworked.
Think of subcutaneous fat as the visible layer you can see and visceral fat as the silent operator behind the scenes, quietly influencing how healthy or unhealthy your body really is.
Fat as an Endocrine Organ
Now let’s talk about something most people never realize. Fat acts like a hormone-producing organ.
That means it doesn’t just store energy. It communicates with your brain, muscles, and organs through hormones and chemical messengers. Healthy fat tissue sends out helpful signals. It releases hormones like leptin, which tells your brain when you’re full, and adiponectin, which helps your muscles use energy efficiently and keeps your blood sugar stable.
But when fat levels rise too high, especially visceral fat, everything starts to shift. Those same hormones that once kept your body in balance begin sending mixed or distorted messages. Leptin stops signaling properly, so you feel hungrier even when your body doesn’t need more food. Adiponectin drops, making it harder for your body to manage insulin.
At the same time, your fat tissue begins producing more inflammatory molecules called cytokines. These chemicals tell your immune system that something’s wrong even when it’s not. The result is a constant state of low-grade inflammation that wears your body down little by little.
So instead of your fat working for you, it starts working against you. It’s like having a thermostat that keeps heating the room no matter how hot it gets. The system keeps firing, and eventually, the whole house overheats.
Chronic Inflammation: the Hidden Connection
That chronic, low-grade inflammation is the real problem. It doesn’t feel like a fever or an infection. It’s more like background noise, always there, quietly draining your energy, slowing recovery, and increasing your risk of disease.
Over time, inflammation interferes with everything from hormone balance to muscle repair. It can make your workouts feel harder, your recovery slower, and your motivation lower. Even your mood and focus can take a hit.
And here’s the kicker. The more visceral fat you carry, the stronger those inflammatory signals become. It’s your body’s way of saying, “I’m under stress,” even if you don’t feel it yet.
This is why fat loss isn’t just about aesthetics. It’s about restoring balance. Reducing visceral fat helps calm inflammation, improve hormone signaling, and bring your body back to a state where it can actually thrive, not just survive.
Putting it All Together
Fat isn’t just fat. It’s a living, talking tissue that influences almost every system in your body. And depending on how much you have and where it’s stored, it can either support your health or slowly work against it.
So instead of thinking, “I just need to lose fat,” a smarter question is, “How can I make my fat healthier?”
Because that’s what real progress looks like. Not just watching the scale go down, but helping your body communicate better, manage energy more efficiently, and reduce inflammation from the inside out.
Tracking Saturated & Trans Fats to Support Lower Visceral Fat with Cronometer
Research suggests that diets higher in saturated and trans fats may contribute to increased visceral fat and inflammation, while replacing those fats with unsaturated sources supports better metabolic health.
You can use Cronometer’s Nutrition Report, found on the Dashboard → Report to review your intake of saturated fat, trans fat, and overall fat quality. This gives you a clear picture of patterns over time so you can make adjustments that support a healthier internal environment. To learn more about the Nutrition Report visit our blog here.
Coming Up Next in This Series
I hope you enjoyed part 1 of our 3 part series on body composition and health. Stay tuned for the next newsletter article for more evidence-based insights to help you live and perform at your best. We’ll explore why body weight alone is a limited metric and how understanding body composition leads to more meaningful health insights. Check out part 3 here.
Best, Dr. Joey Munoz
Nutrition Science Ph.D., Founder of Fit4Life Academy
