November 23, 2018
According to research by the Calorie Control Council, a typical Thanksgiving dinner can carry a load of 3,000 calories. That’s about 500 more calories than most Americans eat in a whole day—and also about 500 more than it takes to gain one pound.
And that’s also why, on the day after the holiday, many of us might be wondering about the pros and cons of intermittent fasting—one of the buzziest diets out there right now. After all, why diet diligently all week when you can drop the excess weight by skipping food entirely just two or three days out of seven?
Fans of this form of dieting say they have lost as much as 8% of their body weight within eight weeks by cutting calories by 20% every other day. They also say they are healthier and have less inflammation.
WebMD theorizes that the possible secret behind the diet’s health benefits is that fasting puts mild stress on your body’s cells. Scientists think that the process of responding to this stress can strengthen the cells’ ability to fight off some diseases—even disorders as serious as heart disease and cancer.
But are these claims legit? Honestly, researchers say, not enough is known yet to confirm whether fasting is advisable or not.
As Liz Weinandy, a staff dietitian at the Ohio State University’s Wexner Medical Center, admitted to Men’s Health magazine in a recent interview, ““I don’t think anybody knows.This is all preliminary.”
In fact, the magazine says, most of the press coverage of intermittent fasting and its purported immune system benefits has focused on just one study: In 2014, Valter Longo— a professor of Gerontology and the director of the USC Longevity Institute—found that cycles of a four-day low-calorie diet that mimicked fasting (FMD) cut visceral belly fat and elevated the number of progenitor and stem cells in several organs of older mice—including the brain, where it boosted neural regeneration and improved learning and memory.
The test was part of a three-tiered study on periodic fasting’s effects—involving yeast, mice, and humans— o be published by the journal Cell Metabolism in June 2015.
Longo and his team had both mice and human cancer patients fast for four days. During the fast, both the mice and the cancer patients discarded old blood cells; once the fast was broken, their bodies produced shiny, new cells to take the place of discarded ones, thus effectively regenerating their immune systems.
In fact, Longo found, in the pilot human trial, three cycles of a similar diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer with no major adverse side effects.
Results of of the study led the USC team to conclude that prolonged periods of fasting could reduce the harsh side effects of chemotherapy for cancer patients—in fact, some patients are already trying this on their own, based on a story posted this year by U.S. News & World Report)—or even boost immunity for healthy people.
A 2015 study by Yale Medical School went one further, finding that hat a compound produced by the body when dieting or fasting can block a part of the immune system involved in several inflammatory disorders such as Type 2 diabetes, atherosclerosis, and Alzheimer’s disease.
Convinced and ready to start? First, read a few cautions from Men’s Health.
First, most intermittent fasting plans recommend not eating between 16 to 24 hours— a much shorter period of time than the four-day fast in Longo’s study. For this reason, Longo says it’s unlikely that his study has any long-term implications about the health benefits of intermittent fasting.
Your body won’t eliminate old cells “until two, three, or four days into the fasting,” he told the magazine. “It takes even longer for the system to start really breaking down muscle, breaking down immune cells, breaking down different tissues.”
Indeed, the report says, future studies will require a broader sample size than Longo’s, so we can determine how fasting affects different groups of people —for instance, the elderly, or diabetes patients, or those with low-functioning immune systems.
What’s more, if you have an active lifestyle, cut back on exercising because fasting could potentially drain your stores of sodium and potassium—two electrolytes that are essential for kidney, heart, and muscle function.
And finally, don’t forget to drink. Water is always a great choice, all day, every day. Sparkling water is fine—but don’t use artificial sweeteners. They will wreak havoc on your insulin levels and defeat your end purposes entirely.
Research contact: melissa.matthews@hearst.com
