Does Intermittent Fasting Actually Work?
Intermittent fasting is the latest fad diet to dominate headlines, complete with endorsements from the likes of Jennifer Lopez and Hugh Jackman. To be fair, reputable medical journals have also speculated there may be certain benefits to intermittent fasting — research has suggested that in animals, the practice can slow the aging process, enhance the ability to cope with stress and improve memory functioning. Proponents of fasting point toward these studies, but the major caveat is that very few have been conducted on humans.
Doctors don't deny that in the short-term, intermittent fasting will result in weight loss. Dr. David Friedman, author of Food Sanity: How to Eat in a World of Fads and Fiction, refers to it as the "starve yourself thin diet."
"Obviously, [intermittent fasting] will cause you to lose weight. It isn’t rocket science," Friedman told SheKnows. "However, when you don’t eat food, the body uses its own fat storage as fuel [and] your body cannibalizes itself. This self-eating state is called ketosis."
He explained that when your body goes into ketosis, you'll begin to lose muscle and become extremely fatigued.
Dr. Susan Besser, a primary care provider specializing in family medicine with Mercy Personal Physicians at Overlea, pointed out that any diet works in the short-term because caloric restriction leads to weight loss. This weight is almost always regained when a person returns to their normal eating habits. But Besser is especially wary of intermittent fasting.
"The variability in calorie intake 'confuses' the body," Besser explains. "The body prefers a stable intake. If you fast, your body thinks there is no food available and will go into energy-conservation mode, such as slowing the metabolism and storing food. Then, when you reintroduce food, the body, now thoroughly confused, hordes the food unsure if there will be another famine soon."
Friedman and Liz Weinandy, a registered dietitian at The Ohio State University Wexner Medical Center, also pointed out that our bodies naturally fast for shorter, healthier periods of time. "I believe we already fast enough during the day," Friedman told SheKnows, "from the time you finish eating at night until the time you wake up, which ranges between 10 to 12 hours."
"Almost anyone can fast for 10 to 12 hours overnight," Weinandy said — for example, it's normal to eat dinner at 7 p.m. and breakfast at 7 a.m. "A benefit here is less time eating late at night, which is typically better for our waistlines."
When patients approach Weinandy about fasting, she suggests the 7 p.m. to 7 a.m. strategy. Then she recommends a diet that includes plenty of fresh fruit and vegetables, legumes, whole grains, lean protein and dairy. "[Patients] are getting in many nutrient-rich foods and at the same time, fueling their body during the day when we need energy the most," Weinandy explains.
Another simple fact is this: Restrictive diets simply don't work in the long-term. Approximately 97 percent of dieters regain the weight they lost (and often a few extra pounds as well). Rather than dieting, Besser suggests making healthy, sustainable lifestyle changes, "such as increased exercise and reduced portion sizes." She advocates for "all things in moderation" rather than imposing restrictive eating rules upon ourselves.
"Although many foods aren't very nutritional, no food is inherently bad for you if you only eat a little," Besser told SheKnows. "So, feel free to give into the cravings in moderation. That will actually keep you from bingeing."