5 Common Side Effects of Going on a Keto Diet


Constipation, headache, bad breath, weakness, nausea and vomiting, headaches—these are some of the surprising side effects of the ketogenic diet, commonly known as ‘keto’.

In this blog, we’ve compiled some of the potentially uncomfortable—or even potentially dangerous—side effects of the keto diet as you decide whether you want to try it.

Common Short-Term Side Effects of the Keto Diet

When starting a keto diet, the body has to use its own fat stores from sugar as its fuel source and may experience some of the following side effects:

  • the stench
  • The keto-flu
  • wearing hair
  • Leg barrier
  • Constipation

the stench

Keto breath is a commonly reported unpleasant side effect for most people following a ketogenic diet. Some describe keto breath as a lingering metallic taste in their mouth. Other adherents of high-fat, low-carbohydrate diets say they get a whiff of something different and a smell like sweet, fruity or nail polish remover. It is caused by acetone, a ketone that is a byproduct of fat metabolism and is released from the body through exhalation. However, the good news is that the keto diet only lasts for a short time. Because the body undergoes significant changes, it is initially more obvious.

Keto flu

Another side effect of eating a high-fat, low-carb diet is the keto flu, a condition that is usually temporary and lasts about a week as your body adjusts to the lack of carbohydrates. Groups of symptoms that mimic the flu may include:

· Extreme fatigue

· Headache

· Nausea Vomiting

· Diarrhea and constipation

· Fever and chills

· Confusion, trouble concentrating and irritability

· Insomnia

· Abdominal pain

· Sugar cravings

· Foggy headache.

wearing hair

One study found that some keto dieters experience thinning hair, possibly for a few possible reasons. First, restricting calories and carbohydrates can limit your intake of various vitamins and minerals your body needs for hair health. Second, there is a dramatic decline in vitamins and minerals (especially zinc and biotin), both of which are associated with hair thinning and loss. Fortunately, this is usually a temporary side effect and often due to a nutritional deficiency.

Leg barrier

Some people may experience leg pain due to dietary changes as a possible side effect of the ketogenic diet. Although these cramps are usually harmless in nature, they can still be annoying. One of the causes of leg cramps on the ketogenic diet is not drinking enough fluids and electrolyte imbalances. This can be alleviated by keeping yourself hydrated, increasing fluids and electrolytes in your diet


One of the biggest health concerns of ketogenic dieters is constipation. The diet lacks carbohydrate-rich whole grains, legumes, fruits, and starchy vegetables like sweet potatoes, which are important for regulating bowel movements. The result? Saying goodbye to high-fiber foods can lead to changes in bowel habits, such as constipation. This can be alleviated by increasing consumption of non-starchy, fibrous vegetables, legumes, nuts, and seeds, as these are all good low-carb sources of fiber.

Other Less Common Side Effects of the Keto Diet

1. High heart rate: This is also called heart palpitations and can occur during the first few weeks of the ketogenic diet.

2. Elevated Cholesterol Levels: Another consequence of the keto-diet is that some people have elevated total cholesterol levels and LDL (bad) cholesterol.

3. Ketoacidosis: People with diabetes need to be very aware of their blood sugar and check their glucose levels several times a day to avoid ketoacidosis, a serious condition that occurs in diabetes when it is not managed properly. This condition has been reported in lactating women, possibly triggered by a very low carbohydrate diet. Although this complication is quite rare.

4. Kidney Stones: Studies suggest that although uncommon, some children with epilepsy may develop kidney stones on a ketogenic diet. So experts recommend regular kidney-function monitoring while following the diet.

5. Fatty Liver: Health experts fear that this can happen if you follow the diet for a long time.

Last thought

Following the keto diet can be challenging for some people. In particular, the first few weeks of transitioning to an eating plan can cause some temporary side effects, and it’s important to be a little more prepared for what’s to come. Not all patients are suitable candidates for the keto diet and it is recommended that you speak with a doctor before incorporating any dietary restrictions.

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