Dear readers,
Let me tell you something that might surprise you.
Your body is not broken. It is not betraying you. Every pound of fat you’ve ever gained was your body doing exactly what it was designed to do — following ancient biological instructions written long before fast food, desk jobs, or Netflix existed.
Understanding how fat is actually created and burned is one of the most liberating things I teach my patients. Because when you understand the why, the what to do about it starts to make a whole lot more sense.
So let’s talk about fat. Really talk about it — no shame, no oversimplification, no guilt. Just science. And a few pearls along the way.
First: What Even Is Fat?
Fat stored in your body is called adipose tissue. It lives under your skin, around your organs, and in places you’d probably rather it didn’t. But here’s what most people don’t know: fat is not just a storage locker for extra calories. It is an active, living tissue. It produces hormones. It sends signals to your brain. It communicates with your immune system.
Fat is not lazy. It is busy — and depending on what kind of signals it’s receiving, it can either protect you or work against you.
There are different types of fat, too. Subcutaneous fat is the soft fat under your skin — the kind you can pinch. Visceral fat is the more dangerous kind, packed around your internal organs deep in the abdomen. Visceral fat is metabolically aggressive — it drives inflammation, disrupts hormones, and increases risk for heart disease, diabetes, and even certain cancers.
Pearl: Not all fat is created equal. Where your body stores fat matters as much as how much it stores. A person with a normal weight can have dangerous levels of visceral fat. This is why I don’t treat the scale — I treat the whole picture.
How Fat Gets Made: The Story of a Cheeseburger
Let’s follow a meal through your body and watch fat get created in real time.
You eat something — let’s say a burger and fries. Your digestive system breaks that food down into its basic building blocks: glucose (from the carbohydrates in the bun and fries) and fatty acids and glycerol (from the fat in the meat and oil).
The glucose enters your bloodstream and your blood sugar rises. Your pancreas senses this and releases a hormone called insulin. Think of insulin as the key that unlocks your cells’ doors, letting glucose in to be used for energy.
Here’s where it gets interesting.
Your cells take what they need for immediate energy. Whatever’s left over — glucose your body doesn’t need right now — gets stored. First, it gets converted into glycogen and packed into the liver and muscles, like a short-term savings account.
But that savings account fills up fast. Once it’s full, your body has to do something with the overflow. So it does what any sensible system would do with excess resources: it converts the leftover glucose into fat — specifically into triglycerides— and ships them off to fat cells for long-term storage.
This process is called lipogenesis — lipo meaning fat, genesis meaning creation. Your body literally manufactures fat from extra sugar and carbohydrates. This is one of the most important things I teach, because most people still believe fat in food is what makes you fat. The bigger driver, for most people, is excess carbohydrate and the insulin response it creates.
Pearl: Chronically high insulin is one of the most powerful fat–storage signals in the human body. If your insulin is always elevated — because you’re always eating, always snacking, always spiking your blood sugar — your body is almost physiologically locked into storage mode. It is very difficult to burn fat when insulin is high. This is the biology behind why constant snacking works against fat loss, even if the snacks seem “healthy.”
The Fat Cell: Not Just a Balloon
People tend to think of fat cells as passive — just balloons that inflate when you overeat and deflate when you diet. That is not what’s happening.
Fat cells — called adipocytes — are dynamic. When you gain fat, those cells don’t just fill up and stop. They grow larger (a process called hypertrophy). And when they reach their limit, your body can actually make new fat cells (a process called hyperplasia). New fat cells, once created, don’t disappear. They can shrink, but they don’t go away. This is part of why losing weight and keeping it off is genuinely harder for people who have been significantly overweight for long periods — the cellular landscape has changed.
Fat cells also release hormones. Leptin is one of them — it signals to your brain that you’re full and have enough energy stored. Adiponectin is another — it improves insulin sensitivity and has anti-inflammatory effects. Healthy fat tissue produces generous amounts of adiponectin. Inflamed, overstuffed fat tissue produces less of it and more inflammatory signals instead.
Pearl: Fat tissue that is inflamed behaves very differently than healthy fat tissue. Inflammation inside fat cells is one of the reasons that obesity drives so many downstream diseases — it’s not just the weight itself, it’s what that inflamed fat is doing metabolically. This is why reducing inflammation — through food, sleep, stress management, and targeted medicine — is central to everything I do.
How Fat Gets Burned: The Good Stuff
Okay — so how do we go the other direction? How does fat actually get released and burned?
The process is called lipolysis — lipo meaning fat, lysis meaning breakdown. Here’s how it works.
When your body needs energy and there isn’t enough glucose available — because you haven’t eaten recently, because you’re exercising, or because you’ve lowered your carbohydrate intake — it sends a signal to fat cells to start releasing stored energy.
The primary messenger for this is a hormone called glucagon — think of it as insulin’s opposite. When blood sugar drops, glucagon rises, and it tells fat cells to open up and release their stored triglycerides into the bloodstream.
Once those triglycerides are released, they get broken down into their component parts — glycerol and free fatty acids. Those fatty acids travel through the bloodstream to the cells that need energy, where they’re taken into the mitochondria (the powerhouses of the cell) and burned for fuel in a process called beta-oxidation.
That is fat being burned. That is the goal.
Pearl: Fat burning requires insulin to be low. You cannot burn fat and store fat at the same time — these are opposing states. Every time you eat — especially carbohydrates — insulin rises and fat burning pauses. This is not a problem if it happens a few times a day. It becomes a problem if insulin never gets a chance to come down. This is the core biological argument for time-restricted eating, lower-carbohydrate approaches, and not grazing all day.
The Hormonal Orchestra
Here’s something I want you to really absorb: fat storage and fat burning are not just about calories in and calories out. They are orchestrated by hormones. And if your hormonal environment is dysregulated, your fat metabolism will be too — regardless of how hard you’re trying.
Cortisol — your main stress hormone — directly promotes fat storage, particularly visceral fat. Chronic stress literally reshapes your body composition. I see this in patients constantly: high-functioning, disciplined people who eat well and exercise, but carry stubborn belly fat because their cortisol is chronically elevated. You cannot out-diet chronic stress.
Thyroid hormones set your overall metabolic rate. A sluggish thyroid means a sluggish metabolism — slower fat burning, more fatigue, more weight gain despite reasonable effort.
Estrogen and testosterone both play significant roles in body composition. Estrogen helps direct fat to the hips and thighs (protective) rather than the abdomen (dangerous). When estrogen drops — as it does in perimenopause and menopause — fat distribution often shifts toward the belly. Testosterone supports muscle mass, and muscle mass is your metabolic engine. The more muscle you have, the more calories you burn at rest.
Insulin, as we’ve discussed, is the master fat-storage hormone. Glucagon is the fat-release hormone. Leptin controls hunger and satiety from the fat cell’s perspective. Ghrelin drives hunger from the stomach.
This is an orchestra. Every instrument matters. Pull one out of tune and the whole performance suffers.
Pearl: When someone tells me they’re doing everything right and still can’t lose fat, I don’t question their effort — I question their hormonal environment. Nine times out of ten, there’s something in that orchestra that needs tuning. This is what labs are for. This is why I don’t guess.
GLP-1: The Game Changer
I’d be doing you a disservice if I didn’t talk about GLP-1 receptor agonists here — medications like semaglutide that have genuinely transformed what’s possible for people struggling with fat loss and metabolic disease.
GLP-1 is actually a hormone your gut produces naturally after eating. It tells your pancreas to release insulin (appropriately, in response to food), tells your brain you’re full, and slows the rate at which your stomach empties — which keeps blood sugar more stable.
GLP-1 medications mimic and amplify this signal. They reduce appetite at a biological level — not by willpower, but by actually changing the hunger signals reaching the brain. They improve insulin sensitivity. They promote fat burning and protect muscle mass when used correctly.
For the right patient, they are a powerful tool — not a shortcut, but a genuine metabolic intervention that makes everything else more possible.
Pearl: GLP-1 medications work best when they’re part of a comprehensive protocol — not used in isolation. The patients I see get the best outcomes are the ones who use GLP-1 support alongside hormone optimization, appropriate nutrition, muscle-building exercise, and the lifestyle foundations that keep the results sustainable long-term.
The Simple Version
I know that was a lot. Let me bring it home simply:
Your body makes fat when there’s more energy coming in than it needs right now — especially from sugar and refined carbohydrates — and insulin is the hormone that locks that fat in storage. Your body burns fat when insulin is low, energy demand is high, and the hormonal environment supports it. Hormones — cortisol, thyroid, estrogen, testosterone — either make this process easier or harder. And when the system is stuck, there are real, science-backed tools that can help move it.
This is not about willpower. It is about biology.
And biology, unlike willpower, can be worked with.
What This Means for You
Understanding your fat metabolism is the first step to changing it. Because when you know that every carbohydrate you eat raises insulin, and high insulin blocks fat burning, you start to make different choices — not from guilt, but from understanding.
When you know that chronic stress is literally storing fat around your organs, stress management stops feeling like a luxury and starts feeling like medicine.
When you know that your hormones are running the show, you stop fighting your body and start working with it.
That’s what I’m here for.
Your Next Step
If you’ve been reading this and thinking, “I need to see what my body is doing.”
This is your sign. The sooner you understand your metabolic patterns, the sooner you can start making progress again.
To get started:
Call our office at 703-666-4144 or schedule a consultation with us.
Dr. Aleksandra Gajer
Founder, The Gajer Practice | Burke, Virginia
Board-Certified Physician | Functional & Performance Medicine
