Fad Diets & The Mouth

Alvin H. Danenberg, DDS Nutritional Periodontist
March 19, 2018 [printfriendly]




Fad DietsAn email about fad diets and bad breath was forwarded to me. This email claimed that some fad diets like fasting and low-carb could lead to dehydration and bad breath in the mouth. This might make sense to some extent about fad diets, but there was an underlying intent.


The ultimate purpose of the email was to promote a dentist-developed, bad-breath lozenge. I’ve already discussed how I feel about healthcare practitioners promoting products, so I won’t go into that here. The issues this email raised for me, however, were the definition of a “fad diet” and the side effects in the mouth. So, let me talk about fad diets as well as the effects of dehydration and bad breath in the mouth.


Fad Diets

Let me be clear: I do not believe in fad diets. I wrote an article that described some fad diets over the past decades. But, what is a “fad diet”?


If a nutrient-dense diet that has sustained our primal ancestors for at least 160,000 years is considered a “fad diet,” then I disagree with labeling it a fad diet. If the diets of various primal societies existing in isolated areas in the world today are considered “fad diets”, then I disagree they are fad diets.


“Fad Diets” are quick fixes to lose weight by removing critical nutrients, which the body requires.


Fasting is Not a Fad

Fasting has been studied and researched for many years. Peer-reviewed medical articles have been published in various medical journals. The overwhelming evidence is that fasting can produce significant health benefits like regulation of insulin and other hormones, repair of mitochondria, and increase in longevity. Of course, drinking water is necessary when fasting. Water does not break a fast.


Low-Carb is Not a Fad

A low to very low-carbohydrate diet and even a “keto diet” have been studied. Our body can make the extra glucose it requires from other nutrients we have ingested. We don’t need excess carbohydrates from our diet. Becoming a “fat burner” and not a “sugar burner” is healthy. However, this may cause a change in odors on the breath. I remind my patients that these odors frequently will go away as these eating styles become stabilized in the body.


One popular diet question I get from my patients is about lean meats. I don’t eat lean meats. I eat meats from pastured or wild caught animals that live humanely in their natural environments and only feed on their natural food sources. I include their healthy fats and their amazingly nutritious organs.


Another popular question I get is about whole grains. Whole grains are problematic, as they have:

  • Phytates that bind to necessary nutrients
  • Proteins that are not completely digested and damage the gut microbiome and the intestinal lining
  • Excess carbohydrates that are unnecessary for healthy metabolism.


However, low-carb is not for everyone. For example, those who are children, are pregnant, have hypothyroidism, or have “adrenal fatigue” should not go “low carb”. I try to talk with my patients about this, not always with success. In general, it is probably fair to say that most people will benefit from eating significantly fewer carbohydrates than are eaten by the majority of individuals in the modern world.



We often hear about how much water we should drink each day. Humans do not need to drink a specific volume of water daily. Your body will tell you when you need water. When you are thirsty, you should drink water – all the water you want. If you are thirsty but you don’t drink sufficient water, then you could get dehydrated. Listen to your body!


Bad Breath

Everyone occasionally will experience bad breath, which is usually caused by the digestion of some odoriferous foods. However, chronic bad breath can be caused by many things –excessive protein consumption, bacterial overgrowth in the mouth and other parts of the digestive system, systemic infections, gum disease & tooth decay, sinus problems, and tonsil stones. Dehydration could cause bad breath by decreasing the flow of saliva.


I explain to my patients that adequate saliva is necessary to begin the digestion of certain foods, lubricate the mouth, and wash away food particles and bacteria. So, a decrease in saliva could cause bad breath by allowing the level of unhealthy bacteria to increase. Adequate saliva also provides necessary nutrients to the healthy microbiome in the mouth as well as the healthy biofilm around the tooth margin called dental plaque. (By the way, dental plaque is healthy until it’s not.)


My Final Comments

Fad diets are unhealthy. They might cause dehydration and bad breath, among other complications. But, a healthy diet of nutrient-dense foods is not a fad diet and will not cause dehydration or bad breath. Let’s be sure to define fad diets correctly. “Fad diets” are quick fixes to lose weight by removing critical nutrients that the body requires.



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