 Every year, hundreds of the top cancer scientists from countries around the world converge to discuss the latest on diet and cancer. I'd like to share what I've found to be the most interesting highlight from this year's conference. First some background. One cancer cell never hurt anyone. Two cancer cells never hurt anyone. But a billion cancer cells? That's when we start getting into trouble. We have to slow and reverse the division in growth of cancer cells. We all have cells that could grow into tumors, but if we slow them down, our immune systems may be able to clean them up before they spell trouble. Take breast cancer. For example, the most common cancer among American women. Like all cancers, it starts with one cell. This is a photomicrograph, a photograph taken under a microscope of an actual breast cancer cell, which then divides and becomes two cells, and then four, eight, and so on. Every time the cells divide, the tiny tumor doubles in size, and the tumor only need double about 30 times, and we're up to a billion cancer cells, which is a tumor just large enough to be picked up by mammography. Even though it only has to double 30 times, it takes between 25 and 1,000 days for cancer cells to double just once. So that means from the time that first cell gets mutated, it takes between two and 100 years before it actually shows up as a little tumor we can see. The shortest known interval between exposure to a carcinogen and cancer is about 18 months, which is when the first leukemia cases started appearing after Hiroshima. Cancers need time to grow, and for most solid tumors, meaning non-blood tumors like breast cancer, cancer can take decades to develop. Many breast cancers may start in the teen years. Some think we actually may start developing breast cancers in the womb before we're even born, and that depends in part on what our mom ate. This is what's called the promotion stage of cancer. 20 years ago, I ate meat, a lot of meat. I very well may have mutated one of the cells in my prostate, liver, or colon, but I don't mind if I get cancer in 100 years. I don't expect to be around to worry about it. The cancer may have been initiated by a DNA mutation, but if we don't promote it, if we keep it dormant, if we slow it down, we may even be able to reverse its growth. According to autopsy studies in Japan, they've got just as much prostate cancer as we do, but the rate of Japanese men dying from prostate cancer is one-tenth that of American men, until they start eating like us. Japan has the number one longest life expectancy of any nation. The U.S. falls around 19th. When Japanese men finally do die, though, many have tiny prostate tumors, but they die with their cancer instead of from their cancer. By age 80, the majority of men have tiny cancerous prostate tumors, and by age 40, one-third of women have microscopic cancerous breast tumors. It's like atherosclerosis. About half of young Americans in their 20s already have atherosclerotic plaques hardening their arteries. Many of us right now have tumors growing inside of us, so we can't wait until later to start eating healthier. We have to start now. How can we slow down and reverse cancer while it's still microscopic? Well, for prostate and breast cancers, these tissues tend to be sensitive to growth-promoting steroid hormones like estrogen. So one way to decrease our levels of these steroid hormones may be to stop eating and drinking them by avoiding eggs, meat, and dairy. Okay, let's get to the new research. UCLA scientists placed women on a plant-based diet with exercise, and the levels of all measured growth hormones in their blood dropped dramatically. That's not new news. It's what they did next that made this one of the most exciting papers to come from that conference. Before and after the dietary change was initiated, researchers drew blood from the women and dripped it on live human breast cancer cells growing in a petri dish. After just two weeks, the blood of women on the plant-based diet reduced the cancer growth rate by 20%. This is before, just packed with cancer. This is after. Just two weeks on a plant-based diet, and the blood circulating throughout their entire bodies was that inhospitable to cancer. Again, many of us right now have tumors growing inside of us, so we can't wait until we're older to start eating healthier. We have to start now, tonight.