How Fat Loss Really Happens
Discover what actually happens inside your body when you lose fat, and how to work with it, not against it.
"The axe forgets, but the tree remembers."
You may not feel each choice or each skipped step. But your body keeps the score, quietly adapting, adjusting, defending. Fat loss is not just about burning fuel. It's about gently persuading your body to let go.
What Is Fat?
Before we talk about losing fat, we must understand what it is.
Fat, stored in adipose tissue, is your body's long-term energy reserve.
It's not poison. It's not failure. It's actually a survival mechanism.
When you eat more energy than you need, your body stores the excess:
- Carbs convert to glycogen or fat.
- Fat is stored directly.
- Protein can be converted to fat if intake far exceeds needs.
Stored fat = stored energy.
Your body doesn't know you're on a diet.
It thinks you're in a time of famine. And it will protect its reserves unless:
- There's a sustained signal of energy shortage.
- The process doesn't feel threatening (e.g. overly fast or stressful).
What Happens When You "Burn Fat"?
Fat is stored as triglycerides in fat cells. To be "burned," they must be broken down and transported for use.
Here's the science-backed process:
- Lipolysis: Hormonal signals (like low insulin, higher adrenaline) trigger fat cells to release fatty acids.
- Transport: Fatty acids enter the bloodstream and are carried to muscles or organs.
- Oxidation: Inside cells, they are burned for fuel (via mitochondria).
The actual "disappearance" of fat?
BMJ: Where does the fat go?
You breathe it out as carbon dioxide (CO₂) and exhale water vapor.
Yes, most fat is lost through your lungs.
What People Get Wrong
"Fat turns into muscle."
No, they are different tissues.
You can lose fat and gain muscle, but one doesn't become the other.
"Sweating = fat loss."
Sweat is fluid loss, not fat loss. You'll regain it by drinking water.
"You have to feel hungry or sore to lose fat."
Nope. Hunger, soreness, or struggle isn't success.
A gentle, sustainable deficit works better and causes less rebound.
"Fast fat loss is better."
Rapid fat loss (>2 lbs/week) often comes from muscle + water + glycogen loss.
This slows your metabolism and increases rebound risk.
NHS recommends approximately 1 to 2 lbs (0.5 to 1 kg) per week for sustainable loss.
NHS: Tips to help you lose weight
How to Work With Your Body
Here's how to approach fat loss in sync with your biology:
1. Create a Gentle Deficit
Aim for ~300-500 kcal/day deficit.
Enough to lose ~1 lb/week, sustainable and reversible.
You don't need to track every calorie:
- • Eat mostly whole foods
- • Use visual portion control
- • Reduce obvious excesses (snacking, sugary drinks)
2. Stay Active, Don't Overtrain
Daily walks, light resistance training, and moving more helps preserve muscle and encourage fat as the fuel source.
- • NEAT (non-exercise activity thermogenesis) is powerful.
- • Overtraining spikes cortisol and may increase cravings.
3. Manage Stress and Sleep
Poor sleep + high stress = elevated cortisol = fat retention (especially belly fat).
Recovery is fat loss fuel.
Think in rhythms, not routines.
4. Be Patient, and Don't Trust the Scale Alone
Fat loss is not always weight loss.
Use:
- • Progress photos
- • Waist measurements
- • How clothes fit
- • Mood and energy levels
Because you can lose fat, gain muscle, and stay the same weight.
The Biology
Your body is not broken. It's just being protective.
Understanding how fat loss actually works removes the mystery and the panic. You don't need to fight your biology, you need to work with it.
Each day you eat with awareness, move with purpose, and rest with respect, your body responds. Slowly, but surely.
Remember: the goal isn't just to lose weight. It's to lose fat while keeping your health, strength, and sanity intact.
Key Takeaways
- Fat loss is not magic. It's a biological process of releasing and burning stored energy.
- Fat loss is not linear. It's a process of ups and downs.
- Fat loss is not a sprint. It's a marathon.
References
Deljo Joseph
Founder of Getter. Marathoner who enjoys skateboarding, cooking, and building products. Specializing in evidence-based approaches to sustainable weight management. All recommendations are backed by established guidelines from the NHS, CDC, and peer-reviewed research.
