The eating regimen called “intermittent fasting” first caught my attention last year when my friend Reid Freeman, 61, who runs a factory in Lexington, Ky., told me he’d been using it to lose weight. He hoped weight loss would help with his obstructive sleep apnea, which is associated with an increased risk of heart attack, stroke and abnormal heartbeats (known as atrial fibrillation, or AFib).
Now three years into intermittent fasting, Freeman recently told me he has shed 45 pounds thanks to it — and even more important, his sleep apnea is gone, which likely reduces his risk of a cardiac event.
I had followed up with Freeman because I’d recently learned that I was at high risk for a heart attack — not because of sleep apnea but because I have metabolic syndrome. That’s a catchall disorder that includes obesity, insulin resistance or hypertension, or a combination of them, that increases the risk of heart disease and heart attack. Based on those risks, my cardiologist, Arthur Agatston, an associate professor at the University of Miami Miller School of Medicine, had recommended intermittent fasting to me.
Intermittent fasting took off in the United States in part due to a 2014 TEDx Talk (“Why fasting bolsters brain power”) by Mark Mattson, a neuroscientist at Johns Hopkins Medicine. There are numerous versions of it: Mattson says the 16:8 plan, in which you fast 16 hours a day, and restrict your eating to an eight-hour window, is the most popular. Other approaches include alternate-day fasting and the 5:2 method, which requires fasting two nonconsecutive days a week.
“There have been no studies comparing the different intermittent fasting approaches in humans,” Mattson says, “so all we can see is that several different [IF] approaches are better than three meals plus snacks every day.”
David Weincek, an actor and friend, followed the 16:8 plan, eating during only an eight-hour window each day. To his surprise, he lost 22 pounds in four months.
“I noticed I had much more energy and stamina during my day,” he told me. As it turned out, dozens of people I know now follow one of these variations, not only for weight loss but also for longevity, cognitive performance, sleep problems — and, relevant to me, heart health.
In case you’re wondering, intermittent fasting isn’t another of those quick-weight-loss schemes you find on the Internet.
Late last year, the New England Journal of Medicine published an authoritative review of research on intermittent fasting and its potential for reducing a great many health risks, including multiple sclerosis, intestinal disorders and various cancers.
One of the study’s co-leads, Hopkins’s Mattson, explained the significant benefits to heart health: “Intermittent fasting enables overweight people to lose weight and improve many different health indicators including glucose regulation, cardiovascular risk factors and inflammation.”
Those risk factors include blood pressure, resting heart rate, HDL (good) and LDL (bad) cholesterol levels, triglycerides, glucose, insulin, and insulin resistance — in other words, metabolic syndrome.
Agatston, my cardiologist, told me he thought intermittent fasting would effectively address my insulin resistance, which is caused by consuming too much sugar and refined carbohydrates (including bread, white rice and pasta). Insulin resistance often progresses to prediabetes, then diabetes, high blood pressure and even atherosclerosis or hardening of the arteries.
And last fall, the American Heart Association reported on two studies showing that intermittent fasting “is associated with lower rates of heart failure and a longer life span.”
The results had a “more profound effect [on heart health] than we anticipated,” epidemiologist Benjamin Horne, who presented the preliminary findings at an AHA conference, explained in a Heart Association news article.
Other medical professionals still want to see more studies to determine the regimen’s short- and long-term benefits, as well as any potential adverse effects.
Carl E. Orringer, director of Preventive Cardiovascular Medicine at the University of Miami Miller School of Medicine, is not currently recommending intermittent fasting to his heart patients. He doesn’t dispute the science in the New England Journal of Medicine article, but he has three concerns about its application in the real world:
●It’s difficult to adhere to, given how culturally ingrained our mealtimes are.
●It may cause short-term hunger, irritability and trouble concentrating.
●Most physicians are not trained to prescribe such regimens.
“I have my doubts about how many patients will actually get access to the counseling and follow-up that will be needed to maximize the suggested benefits,” Orringer told me.
Mattson concedes that new followers are initially likely to “be hungry and irritable during the time when they had previously been eating. . . . However, within two to four weeks their energy-regulating neuroendocrine systems and hunger-regulating circuits in their brains will adapt and they will no longer be hungry during the fasting period.”
It’s all about timing, Mattson says. When you eat a meal, the hormone leptin is released into your bloodstream. “Leptin acts on the hypothalamus,” he says, “and sends signals to higher brain centers, which give you the ‘I’m full’ feeling. On the other hand, when you have not eaten anything for a long time, a hormone called ghrelin is released instead. Ghrelin acts on the hypothalamus to trigger the ‘I’m hungry’ feeling.”
Although it sounds counterintuitive, long periods without eating actually decrease your levels of the “eat now” ghrelin.
How do you start? Agatston told me to start by skipping one meal a day, usually breakfast. (Yes, you can have black coffee in the morning, into which he adds ghee, a type of clarified butter, and coconut oil to reduce hunger pangs. It’s not your typical cup of coffee.) Lunch, he told me, should be in the early afternoon, with dinner no more than eight hours later. He cautions that it’s important to stay hydrated with plenty of water, salt, and magnesium supplementation.
“Adjusting blood pressure and diabetes medication is [also] essential,” he says, all of which means it is important to consult with your doctor before starting an intermittent fasting regimen — and while you’re on it — since it’s not right for everyone.
Finally, there’s one more reason to consider intermittent fasting: covid-19.
Mark Hyman, a practicing family physician, and head of strategy and innovation at the Cleveland Clinic’s Center for Functional Medicine, says nearly 90 percent of Americans are metabolically unhealthy in one way or the other — that is, we have either high blood pressure, high blood sugar or high cholesterol, or a combination. Intermittent fasting, he says, “can improve poor metabolic health resulting in improvements in weight, blood pressure, cholesterol, blood sugar and inflammation” — all of which can make covid-19 illness more severe and life-threatening.
I remain on the fence for two reasons: I’ve been trained over many years that “breakfast is the most important meal of the day.” I want to tend to my heart (and weight) but I also don’t think I’d do well feeling hungry. Still, the science is speaking to me. I’m reminded of what the University of Miami’s Orringer told me: “There is no solution that works for everybody. I just want to see more, high-quality data, before I can give intermittent fasting my seal of approval.”
Yep, that sounds about right.