If you know anything about the dieting world, chances are you have heard of intermittent fasting, a broad term for various diets that cycle between periods of fasting and non-fasting. Whether this is an effective health practice is questionable.
There are many variations of intermittent fasting. Some diets require whole day fasting while others restrict eating to only a certain number of hours per day. In the 5:2 Day Diet, caloric intake is regular for five days and restricted for two days (500 for women and 600 for men). The 16:8 Hour Diet consists of 16 hours of fasting and eight hours of regular eating, typically seen as skipping breakfast and eating two meals after. The Eat Stop Eat Diet alternates between days of normal eating and fasting, and the Warrior Diet involves eating raw fruits and vegetables throughout the day and “feasting” on a large paleo style meal within a four hour period of time at night.
Julian Whitford, a registered dietician studying physical therapy at the UW, is one of three hosts of the nutrition podcast series, “The Three Aminos,” which analyzes different diet fads and their benefits and drawbacks. The hosts did an episode on intermittent fasting and found it difficult to make a broad recommendation given the lack of large scale reliable studies.
“There may be something there, but there simply isn’t enough research at this point,” Whitford said.
In addition to a lack of studies, some believe the side effects of intermittent fasting may outweigh the potential benefits. Fasters may feel irritability and socially isolated from their loved ones or coworkers for skipping meals.
Lauren Rice, another host of “The Three Aminos” and a registered dietician, also believes that the drawbacks of intermittent fasting may outweigh the potential benefits.
“I’m a strong believer in enjoying life,” Rice said. “Are you going to start thinking about food more and do you really want to spend your time on this earth restricting your intake for 25-50 percent of your days?”
Some believe the mentality of restricted eating contributes to disordered thinking around food. Dr. Ramani Durvasula believes that intermittent fasting may place a person at greater risk of developing eating disorders.
“While fasting rarely leads to anorexia per se, it can set into place a set of behaviors and schemas about food, body image that place a person at greater risk of anorexia nervosa,” Durvasula said.
Additionally, over fasting may result in the deterioration of muscles as the body goes into starvation mode and uses ketones, a derivative of protein, as an alternative form of energy.
Intermittent fasting with conditions such as diabetes may be harmful as well.
“Folks with diabetes need to have a consistent intake of food, and practicing intermittent fasting may be dangerous for these people, especially if they practice without consulting a doctor or dietician,” Whitford said.
While some evidence shows intermittent fasting may increase insulin sensitivity, and thus lower a person’s risk of developing diabetes, intermittent fasting with diabetes may be extremely dangerous. When a person fasts, the body releases glucose into the bloodstream, even without eating, causing extreme drops in blood sugar levels which can result in blurry vision, dizziness, and in serious cases seizures and comas.
After speaking with dieticians and conducting considerable research on the topic, I have come to the conclusion that there is simply not enough information to recommend intermittent fasting. While the dieting tactic appears to have helped many lose weight and has potential health benefits, if taken too far, intermittent fasting could be harmful to both mental and physical health.
Whitford recommends taking a mindful approach that focuses on longevity rather than simply what the scale says.
“Anything super restrictive we discourage,” Whitford said. “We like more of an intuitive mindful approach to eating, not cutting out foods, and following a pattern you can maintain for the rest of your life, that hopefully will support your health. ”
Praisers of intermittent fasting claim that it is a good way to lose weight, improve metabolic health, and potentially increase lifespan while criticizers argue the dieting tactic can be dangerous and may lead to disordered thinking.
UW student Phil Cho, a former intermittent faster, highly recommends the diet. While intermittent fasting, Cho’s typical daily routine would be to wake up, go to class, have lunch around 1 p.m., and eat dinner around 5 or 6 p.m.
“Personally, it worked for me. I lost a lot of weight and gained muscle from intermittent fasting,” Cho said.
While there has been a considerable amount of evidence surrounding the health benefits of intermittent fasting, most studies have been conducted on a small scale or on animals. Several small studies have shown that intermittent fasting could potentially reduce the risk of cancer. One study conducted on rats showed that prolonged fasting could potentially reduce oxidative damage and increase cellular stress resistance.
A small study investigated the effect of intermittent calorie restriction on breast cancer risk and found that of the 20 women studied all lost weight, about half showed signs of down regulation on metabolic functions, and three showed signs of change in breast cancer genes.
However, the lack of human studies and small scale studies with inconclusive results is not enough to claim causation between intermittent fasting and increased metabolism and decreased risk of cancer.
Reach writer Christine Lee at firstname.lastname@example.org. Twitter: @christinelee072