 This dramatic strengthening of cancer defenses was after 14 days of a plant-based diet and exercise. They were out walking 30 to 60 minutes a day. Although Pritikin started out reversing chronic disease through diet alone, later to his credit, he added an exercise component as well. And it's great for his patients. But scientifically it makes it hard to tease out which is doing what. Maybe the only reason their blood started becoming so effective at suppressing cancer growth was because of the exercise. Maybe the diet component had nothing to do with it. So they put it to the test. They set up an experiment with three groups. The first group did nothing, control group. The second did diet and exercise, and the third group was just exercise. The diet and exercise group had been put on a plant-based diet for 14 years along with moderate exercise, just like walking every day. The second group was just exercise, but they were hardcore. Not just exercise, but 14 years of daily, strenuous, hour-long exercise like calisthenics. But they ate the standard American diet. In fact, they were actually overweight. They'd been killing themselves in the gym every day for 14 years, and still their BMI average is 26.5. Whereas those on the plant-strong diet were an ideal body weight. But let's see who's better at fighting cancer. The researchers wanted to know if you exercise hard enough, long enough, when you rival some strolling vegans. They took Petri dishes brimming full of human cancer cells and dripped blood from each of the three groups on different dishes to see whose blood was better at suppressing cancer growth. What do you think they found? Whose blood was better at killing cancer cells? This is a graph measuring cancer cell apoptosis, or programmed cell death. Cancer cells are programmed to commit suicide. It's one way our body gets rid of cancer cells. Basically, our immune system taps them on the shoulder and says, look, there's only one way this is going to end, don't you? You take the honorable way out. It'll be quicker, easier. If they start to chemo and everything, it's going to get messy. Take the easy way out and just kill yourself, which our immune system is sometimes capable of convincing cancer cells to do. Here's the blood of the control group. Not very persuasive, cancers like take your programmed cell death and shove it. And as we saw before, here is the effect of the blood of those in the Pritikin group. After 14 years on a plant-based diet, you can bet their bloodstream was clearing cancer cells left and right. But what about the hardcore exercise group in the middle? Did they clear cancer just as good as a Pritikin group? If that's the case, then it wasn't diet at all, right? The exercise was a critical component. Were they somewhere in the middle, showing the exercise helped, but not as good as a plant-based diet group? Or were they down there with the control group? Maybe the exercise helped with other things, but just not at killing cancer. What they found was this. Exercise helped, no question. But literally 5,000 hours in the gym was no match for a plant-based diet. Here's an actual photomicrograph of the cells in the control petri dish stained so they released light when they died. As you can see in the control group, there were a few cancer cells dying. Even if you're a couch potato eating fried potatoes, your body's not totally defenseless. But here's the hardcore, strenuous exercise group, where cancer cells dying left and right. But nothing appears to kick cancer but more than a plant-based diet.