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Keto Diet Side Effects

A Doctor Explains What Negative Side Effects to Expect From the Keto Diet

Photographer: Ericka McConnell

The keto diet, the high-fat, moderate-protein, super-low-carb diet that puts your body into a state of ketosis, has helped countless people lose weight and fight inflammation. And while there are plenty of other positive health benefits, such as helping treat diabetes and transforming your life, there are some negative physical side effects of the diet, too.

When your body goes into a state of ketosis, it starts to burn fat for fuel instead of glucose. By burning through its fat stores, your body produces ketones in the liver. These ketones end up in your urine and your breath, giving you the dreaded "keto breath." The culprit is acetone, a ketone that enters into your breath that can smell metallic or like rotten fruit.

Going into ketosis can also give you dry mouth or a cottonmouth side effect. But these aren't the only unpleasant physical symptoms of the keto diet. In fact, when your body goes into ketosis, it can give you symptoms of dehydration.


"Due to the fact that nutritional ketosis increases sodium (salt) excretion by the kidneys, if a person severely restricts salt intake in combination with this diet, dehydration symptoms like headache, fatigue, exercise intolerance, dry mouth, and constipation can occur," Steve Phinney, MD, PhD, chief medical officer at Virta Health, told POPSUGAR.

These dehydration symptoms aren't super common, but when they occur, they can be unpleasant. As a relief, Dr. Phinney suggests drinking one to two cups of salt-containing broth to replenish the sodium.

Ultimately, you shouldn't make any major dietary changes without consulting with your doctor first. With these side effects in mind, along with the other dangers of the keto diet, it's up to you and your healthcare provider to decide if keto is right for you.

Image Source: POPSUGAR Photography / Ericka McConnell
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