What are some reasons that people fast? For religious traditions or disciplines? To break eating habits? Intermittent fasting has gained attention recently for claims like weight loss, increased productivity and lower risks of heart disease. But is it safe?
What is Intermittent Fasting?
Intermittent fasting is periods of fasting followed by periods of non-fasting.
“This is sometimes called the 5-2 diet — meaning five days of normal eating followed by two days of severe calorie restriction,” said David Winter, MD, chief clinical officer of Baylor Scott & White Health.
People who intermittently fast may also eat only during a certain window of time each day, such as from 10 a.m. and 6 p.m., and they may only allow for water or calorie-free beverages.
But the history of intermittent fasting can be traced back to many years.
“Religious fasting has gone on for years, and studies related to religious and non-religious fasting were able to link its benefits to weight loss and improvements in cardiovascular health,” said Stephanie Dean, RD, a registered dietitian on the medical staff at Baylor Scott & White Health. “Research on these fasts has fueled books, which in turn have fueled a greater popularity of this particular fasting practice.”
“Research on these fasts has fueled books, which in turn have fueled a greater popularity of this particular fasting practice.”
What’s interesting is that at the end of the studies, there is nearly always a statement that says more research needs to be done. These are smaller studies. We’re at a place where it’s getting more public interest, so it is likely to encourage more research.
According to Dr. Winter, “studies on rodents support the idea that limiting feeding reduces the risk of obesity and obesity-related conditions, and may improve metabolic profiles.”
While there isn’t enough research to suggest how long individuals should ease into intermittent fasting, it’s still wise to proceed slowly and check with your doctor or dietitian to see if it may work for you.
“You may want to fast one meal a day — the one you are at risk of overeating,” Dean said. “If you’re concerned about fasting a full 24 hours, drink a protein drink in the place of a meal or snack for a total of 3-5 protein drinks a day and drink coffee, water or unsweet tea the rest of the time.”
Above all, don’t begin intermittent fasting as a fad. It’s a simple solution to breaking some difficult eating habits.
“The calorie restriction element of intermittent fasting has shown to be helpful when people have strong food cravings because they learn that food cravings for a specific item, such as sweets, are often a desire for a sensory experience. Afterward, individuals state that they are more satisfied with healthy food choices and less likely to overindulge on foods they previously craved.”
Intermittent Fasting Concerns
Often times people overindulge outside of their fasts which can counteract the potential health benefits, and fasting for weight loss may only be short-term. Also, extreme hunger experienced with this type of plan may make it impractical and unsustainable.
“It’s similar to the ‘sumo diet’. Sumo wrestlers regularly fast and then follow the fast with a binge,” said Dean. “The danger in following this eating pattern is that fasting can lead to weight loss consisting of both fat and muscle loss. After overeating an individual typically gains fat and not muscle. This can gradually slow down metabolism because your metabolism is impacted by lean muscle mass.”
“It’s not safe for pregnant women,” said Dean, “a study showed that pregnant women who fasted for religious purposes during their pregnancy bore children of shorter stature.”
People who are hypoglycemic or have diabetes should discuss their health goals with their doctor but not implement any kind of fast in their routine.
“Those with a pattern of roller coaster blood sugars, highs and lows, should get those stabilized without going on a fast,” Dean added.