one The Fire in Your Belly T o understand how to lose weight with the 21-Day Belly Fix, you must first understand how the gut works so that you know what you''re up against. And what you''re up against is bad bacteria. As gross as it sounds, bacteria inhabit just about every part of your body, gut included. The tiny ecosystem in our bellies known as the gut microbiota contains tens of trillions of microorganisms. One third of your gut microbiota is common to most humans. Two thirds is specific to you, as unique as your fingerprint. Under normal circumstances, this wide variety of gut bugs coexists peacefully, promoting proper digestive function, strong immunity, and overall vitality. But too many of the wrong bacteria, or not enough of the good ones, can have negative effects.

This imbalance between the beneficial and harmful bacteria in the gut is known as dysbiosis --­the opposite of symbiosis, which describes coexistence in a state of harmony. Dysbiosis can make you feel nauseated, cause belly pain or bloating, or make you gassy (very gassy). Bowel movements change--­you might have to "go" too much (diarrhea) or too little (constipation). You may also feel extremely tired; experience chronic pain from inflamed, aching joints; or feel mentally foggy. Sounds like fun, right? The second characteristic of a healthy gut is a no-­leak intestinal lining, the immune system''s first line of defense. This lining looks like a net with very fine mesh. In a healthy gut, the holes are so tiny that only certain substances can pass through. But if the lining is damaged, the holes get bigger.

All sorts of undesirables--­bacteria, viruses, yeast, undigested food particles--­literally leak out of your small intestine into your bloodstream. The condition''s formal name is "increased intestinal permeability," but it is more commonly known as leaky gut. Leaky gut can also lead to low-­grade, body-­wide inflammation and digestive issues, skin problems like psoriasis, and autoimmune diseases. People with leaky guts may also develop food sensitivities, because partially digested particles of protein and fat leaking through the intestinal wall into the bloodstream causes an allergic response. They may also be less able to absorb nutrients. And they may gain weight. With a leaky gut, the symptoms are all over the map. Digestive symptoms such as gas, bloating, and diarrhea may make life miserable.

Your skin may break out in acne or other rashes. Your mood might change, and you may feel either depressed or anxious. You might develop seasonal allergies or even asthma. I''ve treated thousands of people with leaky guts. Before they come through my door, they''ve seen doctor after doctor, taken test after test, and their symptoms are still a mystery, both to them and to the specialists they see. Tellingly, most Western-­trained doctors don''t believe leaky gut exists. It''s practitioners who embrace alternative medicine systems who typically diagnose and treat it. Here, let me touch briefly on the "second brain," housed in your gut.

Called the enteric nervous system, the gut-­brain is wired to the head-­brain, and they''re in constant communication. When all is well, the messages are quick updates. But if the gut is unhappy, it lets the brain know. A constant onslaught of negative messages from the gut can affect the nerve activity in the brain, leading to disturbances in mood and sleep. But biology is only part of the 21-Day Belly Fix. The principles of Chinese medicine and Ayurveda are also very important to activating its full weight-­loss potential. YOUR DIGESTIVE FIRE In your mind''s eye, picture a roaring campfire. See the tongues of flame leap skyward.

Feel the warmth of the flames on your face, in your bones. Hear the snap, crackle, and pop. Now, imagine that campfire at dawn. The air is chill and damp. The fire is out, or nearly so. No light, no heat. Only scraps of charred wood, a thin wisp of smoke twisting in the air. A fire burning up whatever is thrown into it, efficiently (good!) versus a pile of cold embers that lets whatever is tossed on top sit and rot (bad!).

Those images suggest the two primary states of the digestive system in two ancient systems of healing, Chinese medicine and Ayurveda, the traditional medicine of India. What is digestive fire? Each system approaches it from a slightly different angle. Chinese medicine (see page 8) focuses on diet. The stomach, it says, is a cooking pot; the spleen, which rules digestion, is the fire underneath the pot. Warmed by the spleen, the stomach cooks and breaks down what we eat. Eat well, and you''ll feel well, because the food directly makes up our qi --­our natural energy, a measure of our health and vitality. Ayurveda, which originated in India almost three thousand years ago (see page 6), teaches that within each of us is a digestive fire that converts food to energy, and it''s either in full blaze or a smoking pile of embers. A hot, bright blaze is the source of health, strength, nourishment, and energy.

Yay! You must be eating a balanced diet. A smoky, smoldering fire weakens vitality, setting the stage for disease. Yikes. How many Dove Bars did you eat? That rain-­dampened campfire is the perfect way to picture chronic, low-­grade inflammation in the body. Inflammation isn''t always bad. It''s part of the body''s immune response, a natural reaction to injury and outside invaders. But there are two types of inflammation: acute and chronic. The acute kind of inflammation is a protective response to irritation, trauma, or infection.

Say you get a splinter in your finger. The injured tissue sends out signals to open blood vessels and allow fluids to move from the vessels to the injured tissue. The fluid carries blood cells and other substances that help fight infection and begin the repair process. The familiar signs of inflammation--­redness, swelling, and pain--­are caused by the increase in fluid around the injured area. Chronic inflammation is another story. It''s the damaging immune response caused by a variety of invaders including chemical toxins, food particles your gut can''t digest, and even too much body fat. Like that rain-­dampened campfire, chronic inflammation smokes and smolders continually. And over time, it wears down your immune system, paving the way for disease.

Maybe you already know that studies link chronic inflammation to cancer and cardiovascular disease. What you may not know is that it may play a role in Alzheimer''s, celiac disease (CD), ulcerative colitis, Crohn''s disease, the two most common types of inflammatory bowel disease (IBD), the debilitating autoimmune disease rheumatoid arthritis, and even obesity. Both gut dysbiosis and a leaky gut trigger inflammation. Fortunately, the simple diet and lifestyle changes in the 21-Day Belly Fix help rebalance gut bacteria and seal a leaky intestinal lining, promoting good digestive health and quenching that smoldering, vitality-­sapping inflammation. You can see how combining Western medicine with ancient medicine can benefit you. Agni and Ama In Ayurveda, the three doshas of vata, pitta, and kapha help form our unique constitutions, and they have a specific impact on bodily functions. Doshas are determined through medical history, exams, face readings, tongue and pulse readings, and personality assessments. Furthermore, the doshas impact digestion, each in its unique way.

That digestive fire I spoke of earlier? In Ayurveda, it''s called agni. It''s responsible for absorbing the nutrients the body needs while burning off waste products. When agni is strong, your metabolism hums, your body systems (digestive and others) work well individually and together, and you feel physically and mentally well, strong, and calm. A weak agni means an unbalanced body and mind. You feel sluggish, your mood takes a nosedive, your systems begin to malfunction, your skin and hair grow dull, and your metabolism slows considerably, leading to weight gain. A weak agni is caused by a buildup of ama --­undigested food that forms a toxic sludge within your digestive system. Ama is thought to lead to disease over time. I find it notable that a healthy mix of gut bacteria corresponds to agni, while a strong gut lining is one benefit of reducing ama.

Signs of ama include bad breath, a coated tongue, constipation, fatigue, and depression. (In Ayurveda, the inability to "digest" emotions--­anger, sadness, guilt--­can produce just as much ama as undigested food. Think of it as emotional sludge--­toxic emotions that you can''t eliminate.) To correct ama, Ayurveda recommends an individualized system that incorporates diet, herbal remedies, lifestyle modifications, and purification of digestion through fasting or detoxification. The Chinese-­medicine version of ama is known as "dampness" or "excessive phlegm." In these states, undigested food creates a sticky pudding-­like mass in the body that causes "stagnation." In the language of mainstream medicine, stagnation is the inability of nutrients and blood to help other organ systems. Stagnation leads to "cold," which creates joint pain, constipation, hormone changes, and changes in mental health.

Curing disease starts with correcting dampness or excess phlegm. The healing tools include herbs that relieve dampness, diet changes to reverse cold, and acupuncture to improve stagnation. All of these treatments striv.