Why Cutting Calories Too Low Triggers Starvation Mode - and Backfires

Most people think that if you want to lose fat quickly, you just need to eat less. It seems simple, right? Fewer calories = more fat loss.

Here’s the truth: eating too little won’t speed things up—it can slow your metabolism and even make you gain weight. I knew this already, but curiosity got the better of me. I had to test it—just in case it really did give me that big, quick fat loss result!

My Experiment: Cutting Calories below my BMR

For a few months I’d been eating around 1,800 calories a day, and it was working. My progress wasn’t dramatic, but it was steady and consistent. On average, I lost about 0.3kg of fat per week and gained around the same in muscle.

Some weeks my weight went down, some weeks it went up, but overall, I was moving forward.

Then I thought: “What if I slash my calories and go really low? Could I speed things up?”

So I dropped to 1,400 calories a day—well below my BMR (the number of calories your body needs just to stay alive).

Here’s what happened:

• Monday–Wednesday: I was already starving. Thinking about food constantly.

• Thursday: I had no energy. I found myself needing a sit on the sofa in the afternoon!

• Friday–Sunday: My appetite vanished. I felt moody, had no energy to cook, I was sluggish, and drained. Honestly, I could have just sat and eaten my body weight in crisps and pizza.

But I stuck it out, determined to see the result.

And the result?

On Monday I had gained weight. All of it was body fat, muscle had stayed the same.

Needless to say, I was fuming.

What Is Starvation Mode? | Why did this happen?

When you cut your calories too low, your body thinks it’s starving. It doesn’t know you’ve just decided to diet — it thinks food is scarce and survival is under threat.

So what does it do? It flips into “starvation mode.”

Here’s what starvation mode means

• Your body goes: “Right, we need to keep the heart beating and the brain working. That’s priority number one.”

• To do that, it slows down everything else. Your metabolism — the rate you burn energy — drops right down. That’s why I felt tired, sluggish, and had no energy for my workouts.

• Your body becomes stingy with calories. Instead of burning them, it holds onto them — just in case you don’t eat again. That means more gets stored as fat.

• On top of that, your cravings go sky-high. Your body pushes you towards high-calorie, high-fat, processed foods (like pizza, chocolate, crisps) because it wants the fastest way to stock back up on energy.

So although I ate less, my body responded by slowing down, burning less, and storing more.

The exact opposite of what I wanted.

What Happened Next

The following week, I went back up to 1,800 calories. But my body didn’t trust me right away—it held onto the fat, still in protective mode.

By week two, my results looked like they were stabilising and I had a slight decrease in body fat.

And this is the big takeaway: consistency is everything.

Cutting your calories super low for even a day or two can send your body into starvation mode. Then, when you inevitably eat more (because nobody can starve forever), your body stores those calories as fat.

That’s why “saving calories” during the week so you can splurge at the weekend doesn’t work. Your body isn’t fooled—it’s just confused.

Fat Loss Is Like a Game of Snakes and Ladders

Think of fat loss like playing snakes and ladders:

• Every day you eat consistently at the right calorie intake, hitting your protein, carbs, and fats, you climb a ladder closer to your goal.

• But every time you cut too low or binge too high, you slide down a snake and lose ground.

It doesn’t mean you’ve ruined everything—but it does mean you’ve slowed your journey. The only way to reach the finish line is to keep climbing, one steady step at a time.

Why Consistency (and Honesty) Are Crucial

If you’re serious about fat loss, here’s what you need to know:

• Calorie deficit works—but only a small, steady one. Extreme cuts backfire.

• Consistency beats extremes. You can’t outsmart your metabolism with crash diets.

• Be honest with yourself. Logging, counting, and sticking to your plan are key.

This is exactly why I created my Eat More, Lose Weight program. It’s built around the idea that fat loss doesn’t come from eating as little as possible, but from fuelling your body properly, keeping energy high, and staying consistent.

And if you want step-by-step accountability, my online training gives you the tools, support, and structure to make fat loss happen—without the crash, without the binge, and without the frustration.

Before you ask!!! I know what you're thinking

Why Did I Gain Fat Eating Less, But People on Injections Lose Fat?

This can feel confusing. If eating less slowed my metabolism and made me gain fat, why do people on injections (who also eat less) often lose weight?

Fat loss injections work by changing how your body responds to insulin, the hormone that helps move sugar out of your blood and into your cells. On the surface, this sounds great—it slows digestion, reduces appetite, and makes it easier to eat less. But here’s the catch: eating less through injections isn’t the same as eating well.

Because you’re not taking in enough nutrients, your body can start burning muscle for energy instead of just fat. Over time, this means less strength, a slower metabolism, and a higher risk of regaining weight once you stop the injections.

On top of that, over time, nutrient deficiencies can creep in, leaving you feeling tired, run down, and weaker than before.

It’s a short-term solution that can come with long-term downsides. Without resistance training and proper nutrition, people may actually become weaker and less healthy, even if their weight drops.

Final Thoughts

Cutting calories too low on your own can backfire, slowing your metabolism, lowering energy, and even causing fat gain. Fat-loss injections may seem like a shortcut because they reduce appetite and help manage insulin, but they come with hidden costs—muscle loss, nutrient deficiencies, and weaker metabolism.

The real key to long-term fat loss is consistency, proper nutrition, and fuelling your body enough to stay strong and energized. When you feed your body the right amount of calories, protein, and nutrients, and pair that with movement, you avoid the starvation-mode trap and protect your muscles while steadily losing fat.

That’s exactly why my Eat More, Lose Weight program and online training focus on teaching sustainable habits: eating enough to stay fuelled, managing cravings naturally, and keeping your body moving so fat loss happens safely and lasts. Fat loss isn’t about extremes or quick fixes—it’s about building consistent, healthy routines that last you a lifetime.

See My Results!