The Most Common Causes of a Slow Metabolism

Isn’t it fascinating how some folks can munch on anything without gaining a pound, while others seem to pack on weight just by glancing at fast food or sweets? This is due to a particular part of the human genes, but also due to a “broken” metabolism. People that can eat whatever they want without gaining weight usually have good genes and an extremely well-functioning metabolism. This ensures, among other things, that nutrients are processed better and faster.

That being said, we all have to make sure that we take a good care of our own metabolism, so it can work properly. Key factors include water consumption, protein and fat intake and enough sleep.

Diet plays a significant role in influencing our metabolism. Thus, an intense diet (great calorie deficit) performed for very long periods of time, slows down your metabolism.

Even when the body receives relatively small amounts of energy (depending on body type, size, and weight), a damaged metabolism can prevent weight loss goals from being achieved. The body switches to energy conservation mode as a protective measure, a response rooted in our evolutionary history when food was scarce.

Some theories propose that losing weight becomes challenging after gaining a significant amount. When a drastic calorie deficit is sustained over time, the body enters energy preservation mode, making weight loss more difficult.

Sure, some people might think that pro fitness athletes use extreme diets to bulk up and then drop weight rapidly. While that might happen, it’s because they often use performance enhancing drugs to keep their hormones high and burn fat even on strict diets. So, don’t compare yourself to them because their situation is not the same as yours.

While a slow metabolism can be unmistakably associated with a bad diet, sometimes other things also play a role in how fast your metabolism is.

Since you already know you have a slow metabolism, you next need to find out why your body is acting the way it’s acting. Is it something you do or just your genetics ?

Here are some common causes of a slow metabolism.

1. Very low amount of nutrients and calories

A low calorie diet, which is carried out over a long period will considerably slow down the metabolism. As already mentioned, this takes place as a protective reaction of the body. Usually during a very low calorie diet, the hands and feet become cold as a result of the very low energy supply. The body draws all its blood to the body where is needed the most.

A big mistake by athletes that want to reach their final goal quickly, is starting a very intense diet right away. The body just does not have the time to get used to the drastically reduced calorie intake, and therefore a rapid metabolism shutdown occurs as a result.

This is why you should never start with drastic changes in your diet. Instead, decrease your calories by 10-15% of your total amount of calories. That means cutting down about 300-500 calories per day.

After about 2-3 weeks see how your body reacts and cut another 300-500 calories if necesarry. Some experts suggest taking small diet breaks that last a few days, so you can allow the hormone called leptin to increase and bring your metabolism back on track. This is also how intermittent fasting as a tool works.

2. Very low fluid intake

Another reason for a slow metabolism is often the low fluid consumption. Remember, the human body consists of roughly 65% water. Even without any sport activities you will lose approximately 2.5 liters a day through sweating, breathing or going to the toilet. Digestion of food requires water as well.

Besides digestion, water is also involved in the transport of nutrients, enzymes and hormones in the blood. An interesting fact is that only 2% loss of water will make a person lose a great deal of their strength.

That is why we recommend consuming at least 3 liters of fluids per day if you are physically active. This value will varies according to a person’s height, weight and activity, respectively. A good indicator that you are properly hydrated is the color of your urine, which should be almost colorless or transparent.

3. You don’t eat enough fats

Yes, even when dieting, it is important for the body to have fats. While we don’t need too much carbohydrates while dieting, fats and proteins are absolutely essential to our body. Athletes make a big mistake when they cut the fats almost to zero during a diet.

Make sure you know what kind of fats you consume. Make unsaturated fats primary, and consume just a small amount of saturated fats. Stay away from trans fats at all causes.

Unsaturated fats are essential because they can not be produced by the body, but they are needed to build body cells. You can find them in all sorts of fish, nuts or olive oil.

Saturated fatty acids, however, the body can produce by itself and therefore they are only required in small quantities. They are however needed for the production of anabolic hormones in the body as well as absorption of vitamins such as A, E, D and K. Saturated fatty acids are found in products such as butter, milk, beef steak and chicken drums.

An optimal dosage of essential fatty acids is 0.8 to 1 gram per kilogram a day.

4. You don’t eat enough protein

Fats are important, but protein is even more important. Why is that ?

Simply speaking, proteins are the building materials which your body needs to repair damaged cell structures. This means athletes should always be careful and consume enough protein in the diet. It is only then the body can repair the damage done to muscle fibers by intense exercise.

In addition, a large portion of energy is used just to decompose the protein you eat. This “thermogenic effect of food” short TEF is highest in protein compared to fat and carbohydrates. Therefore high protein diets are better when it comes to cutting body fat.

In combination with intense exercise you need to consume around 1 gram of protein per pound of weight.

5. The last possible cause of a slow metabolism is lack of sleep.

Sufficient sleep is important for a fit mind but also for a fit body. Although it is possible to get away with little sleep occasionally, lack of sleep in the long term can have catastrophic consequences in terms of health.

It is very important to get a good night’s sleep of 8-9 hours, because only then a full regeneration processes take place, and without regeneration no construction is possible.

Many people say that 4-6 hours is just enough for a good night’s rest and everything is a matter of habit. Today, however, there is enough research confirming that sleep is essential for a well functioning metabolism. Too little sleep increases the cortisol levels and consequently leads to muscle breakdown in the long run.

So a good night rest of about 8 hours and even a nap during the day can make wonders for concentration, well-being and sports performance.


The reasons for a slow metabolism can be many, however the few reasons mentioned above, are absolutely in our control. Knowing this, try to correct any mistakes you are making and slowing down your metabolism.

A “broken” metabolism can be annoying but is not a reason to throw in the towel. If you stick to the basics mentioned here, you will surely accomplish long-term success and “fix” your slow metabolism.


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