The nose definitely conditions the air before it gets to the lungs. I will definitely get some mouth tape and give it a try. The book is very interesting. It sure convinced me to stop mouth breathing-or try, exhale more than inhale, and also gave me the idea to get mouth tape. I wonder if you will eventually get subconsciously trained to be a nose breather while your sleeping? and not need tape? Your comments have motivated me to get that tape sooner rather than later. I don't remember him talking about ingredients of processed food but do remember him stressing softer evolutionary foods (now processed) have weakened our jaws and facial muscles due to the lack of chewing. Lots of history on breath (from cavemen to present and all types of breath) and corresponding research-really interesting, especially tummo breathing. Also interesting is the studies done with increasing CO2 in the blood stream and that fast mouth breathers have too little, getting too much air. The result being an inefficiency in our blood chemistry. He and many believe is a contributor to many diseases. He references a study on asthmatics that confirmed their asthma improved when they kept higher CO2 levels up. I plan on getting a pulse oximeter and do some experiments. Thanks for sharing that about the tape!