Feature Archive

Low-Carb Diets Can Cause Bad Breath

Experts offer tips to fight the odor.

By Denise Mann
WebMD Feature

Reviewed By Charlotte Grayson

Low-carb diets may be good for your waistline, but you might not be able to say the same for your breath.

Low-carb lifestyle junkies are more likely to suffer from a seldom discussed side effect of such diets -- halitosis, aka bad breath. And since more than 25 million people say they have tried the Atkins diet (not to mention other low-carb eating plans), according to the National Marketing Institute, bad breath may be an epidemic!

Bad breath in the low/no-carb sect is often caused by certain chemicals that are released in the breath as the body burns fat. They are called ketones, and entering into a fat-burning state of ketosis is the hallmark of the Atkins diet. So the good news is that if your breath stinks, you're probably doing a good job of sticking to that low-carb diet.

"Carbohydrates aren't readily available, so you start to use other fats and proteins as your source of energy, and as a result you are going to get a breath problem," explains Kenneth Burrell, DDS, the senior director of the council on scientific affairs of the American Dental Association.

Pass the Bread?

This is not an oral hygiene problem, Burrell says, so "all the brushing, flossing, and scraping of the tongue that you can do is not possibly enough to overcome this."

The bottom line is that you must "reconsider the diet and modify it so this doesn't happen," he says. Sure, "there may be some ways to mask it by using mouthwashes, but you can't overcome the fundamental problem other than by changing the diet -- or at least introducing some carbohydrates."

"It's a difficult problem to solve because if one uses any sucking candy or lozenge, one has to be careful that it has no sugar in it" as sugar is a big no-no on many low-carb eating plans, says S. Lawrence Simon, DDS, a New York City periodontist. Even so-called "sugar-free" products are often loaded with carbs.

"If you have a metabolic cause of bad breath, there is very little the dentist can do; you have to change your diet," he says.

In fact, "the South Beach diet permits more carbs than the traditional Atkins diet, so there is bound to be less bad breath on South Beach because you are not going into a state of ketosis," he says.

Masking the Problem While Dropping the Pounds

"If I was dropping weight, I would buy more sugarless mints, not quit the diet," says Charles H. Perle, DMD, a general dentist in Jersey City, N.J., and a spokesman for the Academy of General Dentistry.

Perle says that even though this is not an oral hygiene problem, certain things can help banish the bad breath or at least mask the odor.

  • Drink more water.

  • Chew sugarless gum.

  • Suck on sugarless mints. In particular, those that contain Xylitol also kill bacteria and can prevent cavities.

Or, he says, "drink water and swish it around in your mouth after you eat. It moistens the mouth and gets the food particles that may contribute to odor out.

"Basically when you are on a low-carbohydrate diet, the key to success is breaking fat into ketones to create ketosis, and as ketones get into urine and saliva, it can cause horrible breath," Perle tells WebMD.

In fact, this problem is openly acknowledged by the Atkins diet proponents. The Atkins web site states that often this bad breath, while "annoying," is actually chemical proof that you're burning stored body fat.

According to the web site, drinking plenty of water helps dilute the concentration of ketones. In addition, chewing fresh parsley can help.

If your bad breath persists, see your doctor, as it can be a sign of a serious medical condition, such as diabetes.

Published May 14, 2004.

Medically Updated April 7, 2005.