Introduction In all the discussions about the community of microorganisms living in the human gut (the microbiome) and its ‘good’ and ‘bad’ bacteria; in all the science about how to manipulate bacterial populations to increase gut health; and in all the media urging greater awareness of the microbiome’s influence on us all, there has been a missing link. The science of the microbiome has, until recently, largely neglected an active and potentially virulent community within: It is fungus, and it is among us. The fungi in your microbiome may not outnumber the bacteria, but it can compromise your health, contributing to weight gain, digestive problems, inflammatory bowel disorders, and even mood disorders and mental illness. As a research scientist specializing in fungus, I have dedicated my life to the study of the fungi that live in our guts, as well as in and on other parts of our bodies. I’ve witnessed firsthand what kind of trouble fungi can cause. Infections and systemic inflammation are a couple of obvious ways fungi can cause trouble, but they are devious in other ways—fungi can work in an insidious partnership with ‘bad’ bacteria to foil even the most aggressive medications and render useless our most vigorous efforts at dietary control. Intestinal fungi in particular can work with disease-causing gut bacteria, forming sticky biofilms that are a lot like the plaque on your teeth. These biofilms coat the lining of your digestive tract, protecting harmful fungal and bacterial microbes from the body’s immune system, and even from antibiotic and antifungal treatment. But we can outsmart them. Total Gut Balance is the first general-audience health book to explain how fungi work in the human gut, in ways that are beneficial, neutral, and detrimental to human health. If you have recently gained a lot of weight, or are having trouble losing weight; if you have digestive disorders such as irritable bowel syndrome (IBS), stomach pain, bloating after eating, flatulence, belching, nausea, vomiting, acid reflux or heartburn, chronic constipation or diarrhea (or both); if you have a diagnosed chronic disease such as Crohn’s disease (CD), inflammatory bowel disease (IBD), or colitis; or even if you just have a general feeling of poor health and low energy, then you need to know how to manage your total gut balance. It could be a root cause of your health and weight issues. The good news is that gut fungi change rapidly. Gut bacteria, by contrast, is largely established at birth and while it can shift gradually with dietary changes, it can never completely be remade. Not so with fungus. The community of fungi inside and on the surface of a human host (that’s you) is called the mycobiome—a term I coined in 2010 that is now in widespread use in both the scientific community and in popular culture. The mycobiome is dynamic, shifting significantly with every meal. We know that what you eat and do directly influence your gut fungi, and that your gut fungi, in turn, can directly influence what you weigh, how you feel, how well your immune system works, how much inflammation you have, and more. Within 24 hours, you can remake your mycobiome for better or for worse based on what you decide to eat and other factors within your control. When you make gut-friendly choices, you can set yourself on the fast track to total gut balance, which translates to weight loss, better digestion, improved health, and more energy. If you want results and you want them now, fungi are your inroad to a short-term as well as a long-term gut makeover. In this book, you will learn a new way of eating for gut health that specifically targets fungi and takes advantage of its changeable nature. You’ll also learn how to target the beneficial bacteria whose job it is to keep fungi under control. This can help you get the specific and dramatic results you’ve been hoping for, in record time.