Starvation Mode

You’ve probably heard that fasting is bad for your health and that even with a small calorie deficit, your body stops burning fat and starts storing everything you eat as fat reserves.

In this article, we’ll look at:

• What actually happens in the body when we eat too little?
• Why does metabolism slow down?
• How real physiological adaptation differs from the “starvation mode” version on TikTok?
• How to create a calorie deficit in a smart way to reduce fat specifically?

What Exactly Is the Starvation Mode?

The definition is as follows: “Starvation mode” is a physiological body reaction that occurs when the body does not receive enough nutrition for an extended period.

However, the understanding of this process differs significantly between dieters and nutrition specialists.

Dieters and diet enthusiasts often perceive “starvation mode” as a dramatic bodily defence mechanism that switches on when too few calories are consumed. They believe that the body rapidly slows down its metabolism to conserve energy. As a result, weight loss becomes impossible or even causes weight gain. This is often cited as the reason for a weight loss plateau – when weight loss stalls.

Nutrition specialists, on the other hand, use more precise terms, such as “metabolic adaptation” or “adaptive thermogenesis”, by which they mean a physiological reaction of the organism that helps the body survive under conditions of energy scarcity.

Yes, with a large calorie deficit, the body does slow down its metabolism. It can reduce energy expenditure by about 25 per cent. However, this does not completely stop fat burning. If the deficit persists, fat is still burned – just more slowly.

But a weight-loss plateau is actually often caused by other factors, such as inaccurate calorie counting or reduced physical activity.

In short, nutrition specialists focus on physiological processes, not just feelings.

What Actually Happens When Our Body Doesn’t Receive Enough Energy?

First, the glycogen reserves stored in the liver and muscles are used up. This process can lead to rapid weight loss because glycogen binds water, and as its amount decreases, the amount of water in the body also decreases.

As soon as glycogen stores decrease, the body simultaneously initiates two processes:

• It starts looking for the next energy source – fat.
• To provide the brain with glucose, the body begins to break down the proteins within it. Or, more simply put, muscle.

In parallel, the level of the hunger hormone ghrelin begins to rise, and the level of the satiety hormone leptin decreases.

To conserve energy, the body’s basal metabolism and thermogenesis, or heat production, begin to slow down. You start experiencing chronic fatigue and a cold, body movements slow down, the skin becomes drier, and nails and hair grow more slowly. We constantly feel cold, it becomes harder to concentrate, and we become irritable and depressed.

The body begins to use fat as its main energy source – the liver starts producing ketones from fatty acids: beta-hydroxybutyrate, acetoacetic acid, and acetone.

If the calorie deficit is too large and prolonged, for example, three weeks or more, serious tissue degradation begins. 

This process is quite real.

However.

It is fully realised only if you follow some extreme or fad diet for an extended period because you want to lose years of accumulated excess weight in just a few days or weeks.

You might ask: If the “starvation mode” does not exist, then why does the weight of so many people stop or even increase when they start eating less?

The answer lies in our behaviour and the incorrect interpretation of facts.

People start weight loss with a calorie deficit that is too large – for example, only 800 or 1000 calories per day. Such an extreme approach creates enormous hormonal stress and is unsustainable. After a few days or weeks, you can no longer tolerate it, and the classic “slip-up” happens.

You starve all week, but then on one day, you consume a lot of calories, and you are no longer in a calorie deficit. You think: “I starved all week, I only ate one pizza on the weekend, and nothing changed!” Yes – nothing changed because there was no calorie deficit over the week.

Secondly, what does “Eating Little” mean? It is highly subjective.

You think you are eating a little. But perhaps you are simply miscalculating the calories consumed, for example, not counting those hidden in:

• Various drinks – sodas, fruit and vegetable juices, coffee with milk…
• Added during cooking, for example, in oil or salad dressings…
• Eaten without noticing – I just threw a few nuts (or was it a handful?) into my mouth.

The truth is that a calorie deficit ALWAYS works. There are no exceptions, because the laws of thermodynamics apply to everyone.

If your weight doesn’t drop, it’s not the “starvation mode” stopping your metabolism, but your actual calorie intake is still too close to your maintenance level.

What does an extreme calorie deficit look like?

The idea that a larger calorie deficit is better is incorrect. This only complicates your life and significantly increases health risks.

We’re not talking about a deficit of just 300–500 calories. A calorie deficit is necessary to reduce body fat.

But…

Don’t overdo it!

It is normal and does not harm our health to experience a slight metabolic adaptation during weight loss.

Problems arise when the calorie deficit exceeds ~30–40% and is maintained over a long period.

For women, this equates to below 1200 kcal/day, and for men, below 1600 kcal/day. However, these figures are approximate and will depend on your height, weight and level of physical activity. For example, a healthy 15% calorie deficit for petite women may be as low as 1000 kcal/day.

I know that counting calories is difficult for many people.

So here are some signs that may signal that you are eating too little:

1. You think about food all the time.
2. You become irritable and easily annoyed.
3. You feel dizzy or have a headache.
4. You feel constantly tired, even after getting enough sleep.
5. Your hands and/or feet often feel cold.
6. The quality of your workouts and your strength are declining.
7. You have trouble concentrating.
8. You sleep worse than usual.
9. You often have constipation.
10. You crave sweets.
11. Your weight is dropping too quickly (more than 0.5–1% of your body weight per week).
12. Your period is late, or there are changes in your cycle.

How to interpret the results?

• 0–2 signs: The deficit is most likely healthy.
• 3–5 signs: The calorie deficit may be too large — it is worth increasing your calorie intake by 100–200 kcal.
• 6+ signs: You are likely eating too little — it is recommended to review your nutrition plan/diet.

How do you create a calorie deficit that works and does not cause extreme metabolic adaptation?

The goal is not to avoid metabolic adaptation – it will always happen. If only because as weight decreases, less energy is needed to maintain the body. 

The goal is to slow down this process as much as possible and make weight loss more comfortable.

The best weapon in the fight against the increase of ghrelin, the hunger hormone, caused by metabolic adaptation, is protein. Protein creates the greatest sense of satiety and helps preserve muscle mass, which is critically important. The more muscle you have, the faster your basal metabolism is, and it will slow down more gradually during a calorie deficit. Try to include at least 20–30 grams of high-quality protein in every meal.

The second most important factor is strength training. If your metabolism naturally slows down, you have to “speed it up” artificially. Strength training helps preserve muscle and increases energy expenditure.

Significant hormonal changes occur during a calorie deficit. Therefore, it should not be continuous. Start with a calorie deficit of ten to fifteen per cent. A slight feeling of hunger may appear, but it will be easy to overcome. After eight to twelve weeks in a calorie deficit, take a two-week break – return to your maintenance calorie level to:

• Rest psychologically;
• Allow the normal hormone balance level to restore.
• And prevent excessively deep and prolonged metabolic adaptation.

Key takeaways

• Starvation mode as something that stops fat burning — Does not exist. A calorie deficit always leads to weight reduction.
• Metabolic Slowdown or Metabolic Adaptation is a Reality. It happens because the body conserves energy, and as the body becomes lighter, less energy is required to maintain it.
• The biggest mistake dieters make is too large a calorie deficit, which causes health problems, uncontrolled binges, and unconscious calorie intake.

With a large calorie deficit, weight will decrease, of course, but when you start eating normally, it will return. 

You will think that the diet was good because the weight decreased, and you will start starving again. 

And so again and again.

With every subsequent diet, your muscle mass will decrease, and your fat mass will increase.

Your body will become increasingly softer and shapeless. Losing weight will also become harder each time.

Before you start following any extreme fad diet, ask yourself – what exactly do you want to achieve?

• If you want to lose a few excess pounds, the best way is a small calorie deficit combined with moderate cardio exercise, for example, an hour-long walk every day.
• If you want to lose the excess weight accumulated over the years quickly, it is not possible. You can, of course, start following a drastic, very low-calorie diet; your weight will decrease, but you will mostly lose water, gut content, and muscle mass, not fat. You will start eating normally, and your weight will return.
• If you want to achieve a fit and beautiful physique, you must understand that this cannot be done in a week or even a few months. Body recomposition requires a balanced diet, regular strength training, and self-discipline.

Remember – Your Best Self is created with a smart, sustainable approach, not with starvation and stress. The weight loss process is a marathon, not a sprint. And pauses are allowed in this marathon!

Eat well, eat balanced, move, and – be healthy!