Eating a lower amount of carbs per day may have metabolic benefits and support weight loss. But eating too much or not enough of certain nutrients like protein and fats can prevent your body from reaping the benefits.

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Skipping fats and eating too much protein are common mistakes when going on a low carb diet. Getty Images/mixetto

While low carb diets are very popular, it’s also easy to make mistakes on them. To reap all the metabolic benefits of low carb diets, merely cutting back on carbs isn’t enough.

Here are the 5 most common low carb mistakes — and how to avoid them.

While there is no strict definition of a low carb diet, anything under 100–150 grams per day is generally considered low carb. This is definitely a lot less than the amount of carbs in the standard Western diet.

You may achieve great results within this carb range, as long as you eat unprocessed whole foods.

But if you want to get into ketosis — which is essential for a ketogenic diet — then this level of intake may be too high.

Most people will need to go under 50 grams per day to reach ketosis.

Keep in mind that this doesn’t leave you with many carb options — except vegetables and small amounts of berries.

To calculate your net carbs, subtract fiber, sugar alcohols, and other nondigestible carbs from the total amount. These are the carbs to watch on a ketogenic diet.


If you want to get into ketosis and reap the full metabolic benefits of low carb diets, going under 50 grams of carbs per day may be necessary.

Protein is a very important macronutrient that most people consume adequate amounts of.

It can improve feelings of fullness and increase fat burning more than other macronutrients (1).

Generally, consuming more protein should lead to weight loss and improved body composition.

However, low carb dieters who eat a lot of lean animal foods can end up eating too much protein.

When the body doesn’t have sufficient carbs, amino acids from proteins you eat will be turned into glucose via a process called gluconeogenesis (2).

This can become a problem on very low carb ketogenic diets and prevent your body from going into full ketosis.

According to some scientists, a well-formulated low carb diet should be high in fat and moderate in protein.

A good range to aim for is 0.7–0.9 grams of protein per pound (1.5–2.0 grams per kg) of body weight.


Excessive protein consumption on a low carb diet can prevent you from getting into ketosis.

Most people get the majority of their calories from dietary carbs — especially sugars and grains.

When you remove this energy source from your diet, you must replace it with something else.

However, some people believe that cutting out fats on a low carb diet will make your diet even healthier. This is a big mistake.

If you don’t eat carbs, you must add fat to compensate. Failing to do so could lead to hunger and inadequate nutrition.

There’s no scientific reason to fear fat — as long as you avoid trans fats and choose healthy ones like monounsaturated and omega-3 fats instead.

A fat intake around 70% of total calories may be a good choice for some people on low carb or ketogenic diets.

To get fat into this range, you must choose fatty cuts of meat and liberally add healthy fats to your meals.


A very low carb diet must be high in fat. Otherwise, you won’t get enough energy or nutrition to sustain yourself.

One of the main mechanisms behind low carb diets is a reduction in insulin levels (3, 4).

Insulin has many functions in your body, such as telling fat cells to store fat and your kidneys to retain sodium (5).

On a low carb diet, your insulin levels go down and your body starts shedding excess sodium — and water along with it. This is why people often get rid of excess bloating within a few days of low carb eating.

However, sodium is a crucial electrolyte. Low sodium levels can become problematic when your kidneys dump too much of it.

This is one reason people experience side effects on low carb diets, such as lightheadedness, fatigue, headaches, leg cramps, and even constipation (6).

The best way to avoid this issue is to add more sodium to your diet. You can do this by salting your foods — but if that doesn’t suffice, try drinking a cup of broth every day.

At the same time, it’s important to remember that the Food and Drug Administration has set the Daily Value for sodium at no more than 2,300 mg per day. Consuming more than this amount can be very dangerous for your health, particularly as a risk factor for high blood pressure (7).

In most Western diets, consuming too little sodium is generally not a concern. In addition, the kidneys are quite good at regulating electrolyte levels and maintaining chemical balance in the body after adjusting to a low carb diet.


Low carb diets lower your insulin levels, making your kidneys excrete excess sodium. This can lead to a mild sodium deficiency.

Your body is designed to preferentially burn carbs. Therefore, if carbs are always available, that’s what your body uses for energy.

If you drastically cut back on carbs, your body needs to shift to burning fat — which comes from either your diet or your body’s stores.

It can take a few days for your body to adapt to burning primarily fat instead of carbs, during which you will probably feel a little under the weather.

This is called the “keto flu” and happens to most people who go on ultra low carb diets.

If you feel unwell for a few days, you may be tempted to quit your diet. However, keep in mind that it may take 3–4 days for your body to adjust to your new regimen, and full adaptation may take several weeks.

Use your judgment to decide whether this diet is working for you and whether you’re willing to continue. As with any new diet, it’s a good idea to consult a dietitian or another healthcare professional before you start.


On a low carb diet, it can take a few days to overcome unpleasant symptoms and several weeks for your body to fully adapt. It’s important to be patient and not to abandon your diet too soon.

Low carb diets may offer a potential solution for health conditions like obesity and type 2 diabetes. (8, 9, 10).

However, just cutting back on carbs isn’t enough to lose weight or boost health. The best way to achieve long-term, sustainable weight loss is through small healthy lifestyle changes over time.

Ketogenic diets are often not sustainable in the long term, and dieters often gain weight back when they begin eating carbs again.

For optimal well-being, aim to eat a well-balanced diet and get enough exercise.