In the end it’s not the years in your life that count. It’s the life in your years.
NOT ONLY CAN FASTING REDUCE YOUR RISK OF developing diabetes and cancer, but it can also play a role in reducing the incidence of heart attack. In chapter 3, I mentioned the twenty-year longitudinal study at the Wisconsin National Primate Research Center and these scientists’ investigation of the effects of CR on rhesus monkeys. One reason they chose rhesus monkeys for this study is because age-associated diseases in rhesus monkeys have been thoroughly studied and documented by this center and other labs nationwide. Secondly, studies show that chronic diseases in rhesus monkey are similar to the ones observed in humans. The most prevalent—diabetes, cancer, and cardiovascular disease—mirror those of people.
Since the age-associated diseases are similar in both humans and rhesus monkeys, the hope is that studying the long-term effects of fasting on monkeys could provide a useful insight on how protracted, controlled fasting might impact humans. As I mentioned earlier, not only did more of the animals on controlled fasting survive much longer (80 percent, compared to 50 percent of those fed normally), the scientists noticed that fasting delayed the onset of age-related diseases in animals.2
In a parallel study at the National Institute on Aging (an arm of the National Institutes of Health), researchers investigated the impact of caloric restriction (controlled fasting) on both life span and health span. In 2012 this group published an update in the journal Nature to highlight its findings. After many years of research and observation this group concluded that fasting offers extensive health benefits, and called for separation between the health benefits of fasting and its possible life-prolonging effects. In all these studies, not only was fasting beneficial in reducing risk of cancer and diabetes, but it was also especially helpful in reducing incidence of cardiovascular diseases.3
It is important to note that the National Institute on Aging study did not offer any conclusive evidence that calorie reduction provided clear life-extension effects. Yet the study found that fasting provided immense health benefits, including cardiovascular health. This is consistent with the findings at the Wisconsin National Primate Research Center. Based on these parallel, twenty-year longitudinal studies, there may be some question about the ability of fasting to extend human or primate life span. Still, there is no doubt that fasting provides sound health benefits that improve health span.
As part of the previously mentioned CALERIE (Comprehensive Assessment of the Long-Term Effects of Reducing Intake of Energy), researchers examined the potential health benefits of fasting in sedentary, non-obese, healthy individuals. But a part of their study focused specifically on the effect of prolonged, controlled fasting on cardiovascular health. The study examined thirty-six humans, each randomly assigned to one of three groups. The control group ate normal meals for six months, the second group did a controlled fast (25 percent reduction of normal energy intake for six months), and a third group reduced its energy intake by 12.5 percent, with a 12.5 percent energy expenditure through aerobic exercises.
Researchers examined cardiovascular risk factors for these groups at three- and six-month timelines, using these figures to estimate ten-year cardiovascular disease (CVD) risk in healthy, non-obese men and women. The results of their study were published in 2009 with a rather telling title: “Caloric restriction alone and with exercise improves CVD risk in healthy non-obese individuals.” This conclusion was based on favorable changes in lipid and blood pressure levels, which reduced the risk of CVD.4 Results from the second phase of these trials were expected to provide more conclusive data regarding the role of fasting in improving cardiovascular health. Meanwhile data from most animal studies show conclusively that calorie restriction does have beneficial effects on heart health.
To better understand the role of fasting in reducing the risk of cardiovascular diseases, let us examine the risk factors and causes of CVD. Atherosclerosis is a major disease condition in which plaque builds up in arteries. Over time plaques—made up of calcium, fats, cholesterol, and other substances—harden and begin to narrow the arteries. The arteries are blood vessels that carry blood (including oxygen and nutrients) to various parts of the body, including the heart, brain, kidney, and other organs. When plaques build up, they narrow arteries and significantly reduce blood flow. The tendency to form blood clots, which further impedes blood flow, is higher. Since atherosclerosis can affect any artery in the body, different diseases may develop, depending on which artery is affected.5
Plaque buildup in atherosclerosis is the main cause of three deadly diseases generally grouped as cardiovascular diseases—coronary artery disease, cerebrovascular disease, and peripheral artery disease. Coronary artery disease has to do with sudden rupture of plaques in heart arteries. Plaques in arteries that carry oxygen-rich blood to the heart can rupture and form clots, which may cause the muscles of the heart to die. When this happens, it is known as a heart attack.6 On the other hand, cerebrovascular disease is caused by rupturing of plaques in arteries that carry oxygen-rich and nutrient-rich blood to the brain. This is what causes a stroke. Finally, peripheral artery disease occurs when arteries carrying blood to the legs become blocked by plaques, which reduces free circulation of blood. This may result in the inability of wounds to heal well, or pain when walking. If this persists, it may lead to amputations.
The following data published by the American Heart Association, and reproduced verbatim, illustrates the seriousness of cardiovascular diseases:
• Cardiovascular disease is the leading global cause of death, accounting for 17.3 million deaths per year, a number that is expected to grow to more than 23.6 million by 2030.
• In 2008, cardiovascular deaths represented 30 percent of all global deaths, with 80 percent of those deaths taking place in low- and middle-income countries.
• Nearly 787,000 people in the US died from heart disease, stroke and other cardiovascular diseases in 2011. That is about one of every three deaths in America.
• About 2,150 Americans die each day from these diseases, one every forty seconds. Cardiovascular diseases claim more lives than all forms of cancer combined.
• About 85.6 million Americans are living with some form of cardiovascular disease or the after-effects of stroke.
• Direct and indirect costs of cardiovascular diseases and stroke total more than $320.1 billion. That includes health expenditures and lost productivity.
• Nearly half of all African American adults have some form of cardiovascular disease—48 percent of women and 46 percent of men.
• Heart disease is the leading cause of death in the world and the United States, killing over 375,000 Americans a year. It accounts for one of every seven deaths in the nation.
• Someone in the US dies from heart disease about once every ninety seconds.
More on heart disease
• From 2001 to 2011, the death rate from heart disease fell about 39 percent—but the burden and risk factors remain alarmingly high.
• Heart disease strikes someone in the US about once every forty-three seconds.
• Heart disease is the No. 1 cause of death in the United States, killing over 375,000 people a year.
• Heart disease is the No. 1 killer of women, taking more lives than all forms of cancer combined.
• Over 39,000 African Americans died from heart disease in 2011.7
So what causes these dangerous plaques to build up in the first place? The major risk factors for atherosclerotic diseases include high low density lipoprotein (LDL) cholesterol, low high density lipoprotein (HDL) cholesterol and high triglycerides levels, high blood pressure, diabetes mellitus, and smoking. Atherosclerosis is believed to start with damage to the endothelium (innermost layer) of arteries, which in turn is caused by high cholesterol, smoking, or high blood pressure.8 Once the endothelium is damaged, cholesterol is able to enter the wall of the artery, causing white blood cells to be released in order to digest the LDL. Over time progressive accumulation of LDL combines with cells and calcium to form a plaque in the wall of the artery.
Here is where fasting becomes so significant: to date, in almost all studies involving rodents, all these risk factors for CVD (except smoking) were significantly reduced through calorie restriction directly, or through weight loss resulting from fasting. In other words, studies involving rodents conducted for decades show that fasting (calorie reduction or intermittent fasting) consistently reduces bad cholesterol levels, triglycerides, and high blood pressure.
It is true that using rodents for CVD model has its limitations in humans, since CVD type that occurs in humans is different in some ways from CVD models in rats.9 Still, studies show that similar risk factors predictive of cardiovascular risk—such as oxidative stress—show the same downward spiral during fasting in both animal and human studies. Also important is the fact that similar improvements in CVD have been observed in nonhuman primates, as the two results cited previously show. And in case there is any doubt that these benefits observed in animal models are transferrable to humans, the first phase of the CALERIE study showed that even six-month calorie restriction reduces CVD risks in humans.
There are several more published studies demonstrating the beneficial effects of fasting, or intermittent fasting, on reducing the risk of heart attack. My goal is not to provide an exhaustive review of all reputable articles, but to lay a firm foundation for you to appreciate the immense scientific evidence supporting the idea of the benefits of fasting on cardiovascular health—benefits that apply whether discussing simple animals, nonhuman primates, or humans.
Given this reality, it is time to protect your heart. Studies show that people who fast periodically or generally reduce their energy intake on a daily basis (what some call a “fasted lifestyle”) are less likely to experience heart attack. This calls for action. All these studies and health benefits will not mean much unless you start doing something about it. It is time to consider your own unique fasting program, one that will fit your needs and situation. As I have already mentioned, you can simply start by skipping a meal or two regularly. Or you can start by generally reducing your regular food intake by 15 to 40 percent. Or start by fasting once or twice a week during the day before eating a normal evening meal. It doesn’t matter how you start. The important thing is to start—today.
Resist the temptation to turn this into another weight-loss fad. That is why I have devoted so much time to showing you the scientific studies that support fasting. I want to avoid the tendency of the public to boil things down into some supposedly simple, seven-step program or a fancy slogan. Fads will come and go, but a personal decision to cut your energy intake and fast periodically will produce lasting results. This is about a lifestyle change that will bring you immense health benefits over the long term.