In recent years, diets like Keto, Atkins, Paleo, and Dukan have gained popularity because of their effects on weight loss. Some people swear by low carb diets, while others warn of their potential side effects.

Low carb diets have pros and cons: though they may help you lose weight and control food cravings, they may also lead to nasty side effects such as poor digestion or headaches. It’s important to evaluate all the pros and cons before going on a low carb diet.

In this article we will have a look at the advantages and disadvantages of reducing carbohydrates, so you can get a general idea of what to expect. If you don’t have time to read the whole post, feel free to skip to the summary at the end.

Advantages of low carb diets

1. Weight loss

Diets that are low in carbohydrates can be very helpful if you are trying to lose weight. Because carbs are the body’s main energy source, when you restrict them, your body is forced to use stores of glucose, glycogen, and fat for energy.

If you follow a diet that is extremely low in carbs (for example, one with less than 50 grams per day), your body will actually change its metabolism. Your liver will turn fat into acids called ketones, and send them into the bloodstream to give you energy.

Many people have noticed that eating less carbs led to a significant decrease in their appetite and body weight, and many scientific studies have shown that there is a direct correlation between a low carb diet and weight loss.

Though it is undeniable that restricting carbs aids in weight loss, it may be a sudden, short term result that isn’t necessarily advantageous over time. There is some evidence that over the course of one or two years, a low fat diet may have very similar results or even the same results.

2. Good for diabetes

A low carb diet will help you maintain stable blood sugar levels. Research has shown that carbohydrate restriction is beneficial to those who suffer from diabetes — both type 1 and type 2 — as it helps them control the glucose levels in their blood.

It’s important to note that while diabetics must limit their carb intake, they should not try to cut out carbs completely. As we’ll see in a bit, some foods containing carbohydrates, such as fruit and vegetables, also contain vitamins and minerals that are essential for good health.

This is why the general recommendation is to choose carbs wisely, rather than to eliminate them altogether. Some of them are beneficial; others are terrible for your health. For example, an apple is low in calorie and provides high amounts of fiber, potassium, vitamin C, and vitamin B6; a can of soda contains way too much sugar and zero healthy nutrients.

3. Appetite control

Over time, reducing carbs in your diet will help you control your food cravings. One of the main reasons this happens is that low carb diets are naturally high in protein.

Studies have shown that high protein meals make you feel fuller faster because proteins tend to lower ghrelin, which is the hunger hormone. When ghrelin is low, you will automatically feel more satiated, even if you haven’t eaten a lot of calories.

Another interesting factor is your willpower. As we’ve seen, carbohydrate restriction will help you keep your blood sugar stable throughout the day. When blood sugar levels are stable, there will be optimal blood flow to your brain, so it will be easier to use your willpower and discipline, and control junk food cravings.

To prevent blood sugar spikes, it is essential that you avoid simple carbs — candy, soft drinks, breakfast cereal, cake, and processed fruit juice. Complex carbs, such as whole grains, are not as bad.

Low carb diets can reduce cravings

4. Stable energy levels

Some people find that a low carb diet helps them be alert, active, and productive for long periods of time. This, again, has to do with your blood sugar levels: some carbohydrates tend to cause quick spikes, or drops, especially in large quantities, so reducing them will help you control your glucose levels.

Or, it may have to do with a hormone called serotonin. You may have noticed that after a big portion of rice or pasta you tend to feel sleepy: one of the reasons is that carbohydrates stimulate the production of serotonin which, in turn, can make you feel lethargic.

Low carb diets have often been praised for their health benefits, but what about the potential risks? Keep reading to discover the six disadvantages of carb restriction…

Disadvantages of low carb diets

1. Hard to stick to

Why do so many diets fail? Because while they do work in the short term, they are very hard to stick to. Many people who go on a diet feel enthusiastic and motivated, and may even notice the health benefits in a relatively short period of time.

However after a while, they usually find it difficult to keep eating (or eliminating) certain foods, which is why they go back to their previous diet. One of the main disadvantages of a low carb regimen is that it’s hard to stick to, especially if you love carbohydrates.

Diets are supposed to be part of your lifestyle, rather than a temporary quick fix, so it’s important that you are honest with yourself and choose one you can have for months or even years, realistically.

If you find it very hard to reduce carbs (especially if you follow an extreme diet, such as the keto diet, in which you are supposed to eat less than 50 grams of carbs per day), then you may want to find a better, more practical alternative.

2. Low energy or headaches

As we’ve seen earlier, some people find that a low carb diet is good for productivity because it keeps their energy levels stable. Unfortunately, others find that reducing carbohydrates — the body’s preferred energy source — makes them too tired.

This is particularly true for athletes, people who exercise intensely, or those who have physically demanding jobs. If you are very active, a low carb diet may not be the right one for you, regardless of how many calories you eat each day.

Some athletes have noticed that while reducing their carb intake would help them lose fat faster, they would not be able to do long workouts, a least not with the same intensity.

Another nasty side effect of low carb diets is headaches. This may happen either because of hypoglycemia (low blood sugar levels) or electrolyte imbalance. If your carb intake is extremely low, minerals like potassium, magnesium, and sodium can decrease quickly, and you may be at risk of dehydration.

3. Poor digestion

It’s important to understand that you may experience digestive issues with any kind of dietary change, not just Keto, Atkins, Paleo, or any other low carb regimen. It’s relatively common to experience bloating or loose motions when you change your diet, especially if it’s a sudden change. Luckily, most of the time the symptoms will go away as your body adjusts.

Having said that, reducing your carb intake may lead to poor digestion, for two main reasons. For one, low carb diets are usually low in fiber as well. When you stop eating — or eat less — fruit, dried fruit, potatoes, rice, or pasta, it can be hard to consume enough fiber.

Fiber is essential when it comes to good digestion, and it helps prevent constipation. If you are on a low carb diet, make sure you consume a lot of vegetables: they are high in fiber, but low in carbohydrates.

The second main reason low carb diets can lead to an upset stomach is that you may end up eating foods that are bad for digestion. For example, you may consume a lot of dairy or sugar substitutes such as stevia, aspartame, or sugar alcohols, which are bad for your tummy.

4. Poor sleep

When you eat carbohydrates such as rice or potatoes, your body produces an amino acid called tryptophan. In turn, this amino acid boosts serotonin levels, which make you feel sleepy and increase the quality of your sleep.

Foods like eggs, cheese, and turkey do contain tryptophan, however your body needs insulin to convert it into serotonin: without enough carbs, it is likely that your sleep quality will decrease, and you will find it harder to fall asleep.

One trick to have a low carb diet and still get perfect sleep is to eat your main meal (or at least the one containing the most carbs) a couple hours before you go to bed — though it’s not guaranteed to work. If you have a low carb diet and experience long term insomnia, you may want to switch to a different food plan.

5. Nutrient deficiency

By forcing yourself to eat a limited amount of carbs — say, 100 grams each day — it can be hard to get in all the essential nutrients you require daily. This is especially true if you follow a diet that is extremely low in carbohydrates, such as the Keto diet.

Some of the nutrients you may be missing include vitamin B1 (which helps you turn food into energy), which can be found in whole grains, fortified breakfast cereal, and beans; and vitamin C (essential for the immune system), which can be found in fruit and vegetables. Plus, as we’ve seen, minerals like potassium, magnesium, and sodium can decrease quickly on a low carb diet.

Besides nutrient deficiency, you should also pay attention to the amount of saturated fats you consume daily. Too much saturated fat can build up the “bad” cholesterol and increase the risk of heart disease. If you eat a lot of dairy, red meat, butter, oil, or processed meat, then it is likely that you are consuming way too much saturated fat.

6. Liver and kidney problems

If you follow a low carb diet, you need to get your calories from fat and protein. Unfortunately, this can lead to health problems. Eating too much fat may lead to or increase the risk of fatty liver disease; eating too much protein can put excessive strain on the kidneys, and accelerate damage in people who have kidney disease.

The problem with carb restriction is that you have no choice but to eat more fat and protein. Though a low carb diet will probably help you lose weight and suppress your appetite, you have to look at the big picture and decide whether your diet truly makes you healthy — both in the short term and in the long term.

Pros and cons of low carb diets: summary


  • They make you lose weight fast, although low fat diets have very similar results after one or two years
  • They are usually good for diabetes as they help you maintain stable blood sugar levels
  • Because of the high protein intake, they make you feel full and help you deal with food cravings
  • They may help you be productive for long periods of time, because of stable glucose levels and low levels of serotonin


  • They can be hard to stick to after the initial weeks or months
  • They may cause headaches or low energy levels: reducing carbohydrates means reducing the body’s preferred energy source
  • They are low in fiber, which isn’t good for digestion, though you can experience digestive problems with any dietary change
  • You may have a hard time falling asleep as your body won’t produce enough serotonin (and consequently melatonin)
  • It can be hard to get in all the essential nutrients, particularly vitamin C, vitamin B1, potassium, magnesium, and sodium
  • You have no choice but to consume a lot of proteins and fats, which can put excessive strain on your liver and kidneys

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