Let’s keep it simple: if you want to lose fat, you need to be in a caloric deficit.
That’s it. That’s the real, science-backed “secret.” No matter what diet you’re on—keto, paleo, intermittent fasting, whatever—fat loss only happens when you’re burning more calories than you’re taking in.
So what is a caloric deficit, exactly?
It’s when your body uses more energy than you’re feeding it. You can think of it like this: you’re either eating less than you burn, or burning more than you eat—same idea, just switched.
Everyone has something called a maintenance level—that’s the number of calories your body needs each day just to function. That includes everything from workouts and walking to brushing your teeth and even sleeping. Yep, your body is always burning calories, even when you’re doing nothing.
And here’s the key: we get that energy from food.
So depending on how much you eat vs. how much you burn, ☝🏼of three things can happen.
1. If you eat exactly the number of calories your body needs each day, you’re at what’s called your maintenance level.
That means your weight stays the same—because your body got just the right amount of fuel. Not too much, not too little. Every calorie you took in gets used, so there’s nothing left to store and no need to burn extra from your body.
2. If you eat more than your body needs—meaning you go over your maintenance level—those extra calories don’t just disappear. Your body stores them for later. And guess what form it loves to store them in?
That’s right, body fat.
This is called a caloric surplus, and it’s the one and only reason fat gain happens. Not cookies, not sugar, not eating after 8 p.m.—just consistently eating more calories than you burn.
3. Now, if you eat less than your body needs—aka, you’re in a caloric deficit—your body still needs energy to function, but it’s not getting enough from food.
So what does it do? It taps into stored energy (a.k.a. body fat) to make up the difference.
That’s how fat loss happens. Not by cutting out entire food groups, doing endless cardio, or surviving on lettuce—just by consistently being in a slight calorie deficit over time!
| Calorie State | What It Means | Result |
|---|---|---|
| Caloric Surplus | You eat more calories than your body burns. | Fat gain (extra calories get stored—usually as body fat) |
| Calorie Maintenance | You eat the same number of calories your body needs. | Weight stays the same (all calories are used, nothing stored) |
| Caloric Deficit | You eat fewer calories than your body needs. | Fat loss (your body burns stored fat for fuel) |
For example, let’s say you maintain your weight eating 2,000, calories per day.
If you start eating 2,500 calories a day, you’ll be in a caloric surplus—and over time, you’ll gain weight, mostly in the form of body fat.
But if you drop down to 1,500 calories a day, you’ll be in a caloric deficit—and that’s when fat loss happens.
Here’s the 🔑 point:
This holds true no matter where those calories come from—whether it’s carbs, fats, or protein… healthy, unhealthy, clean, dirty, organic, fast food, whatever.
* With that said, it’s obviously better for long term health to eat healthy foods more often than not.
Timing doesn’t change it either.
Eat after 8 p.m.?
Three big meals or six small ones?
Every two hours or every six?
Doesn’t matter.
What matters most is the total number of calories you’re eating in relation to how many you’re burning.
Exercise Does Help:
Exercise can play a role in a caloric deficit.
The example I gave showed how you can create a caloric deficit just through diet (eating fewer calories). But here’s the thing: you can also create that same deficit through exercise by burning more calories.
So, in the same scenario, you could’ve eaten 2,000 calories but burned an extra 500 through exercise. That would still put you in a caloric deficit and lead to fat loss. Or, you could do a mix of both—eat a little less and move a little more. Either way, you’d create the same result.
But no matter what method you choose, the rule stays the same:
To lose fat, you’ve got to be in a caloric deficit!
Other Fat Loss Diets and How They Work
There are many diets to choose from out in the world. There’s new one’s and one’s that have been around for decades. In the end they all aim to do the same thing, create a caloric deficit.
Paleo, vegan, low carb, high protein, only eating a certain amount of hours per day and so on. All of these “diets” are marketed for fat and weight loss. All of these diets are built for a caloric deficit but that’s not a sexy way to market and make money lol!
Indirectly these diets will more than likely help put you in a caloric deficit which will then in turn make you lose fat. But why is that? Glad you asked here’s some examples 👇🏼
- Eating less carbs means you’re eating less calories. (LOW CARB)
- Eating less fat means you’re eating less calories. (LOW FAT)
- Eating less “dirty” junk food means you’re eating less calories. (CLEAN EATING)
- Eating less processed foods means you’re eating less calories. (CLEAN EATING)
- Eating less grains means you’re eating less calories. (HIGH PROTEIN)
- Not eating after 7pm causes you to eat less calories. (INTERMITTENT FASTING)
- A vegan diet, paleo diet or any remotely similar diet eliminates many of the foods you were regularly eating, which means you’re now eating less calories.
Choose which ever diet strategy you feels works best for you and one that you see yourself following for the long term.
If you tried and failed at one of these diets all that means is you were not in a caloric deficit. Lower your calories or up your movement aka exercise.
Bringing it Together
In the end there are a lot of factors and different ways you can go through fat loss. The one thing I hope you take away from this is not matter which way you go a caloric deficit must be achieved for it to work.
Consider reading Protein: The Powerhouse Nutrient Your Body Needs and How to Count Calories for Health and Weight Loss: A Simple Guide for more guidance oh losing fat.
I hope this helped and as always if you have any questions don’t hesitate to ask!
