A Licensed Dietitian Explains If There Are Legitimate Health Benefits To Fasting

Fasting, and specifically intermittent fasting, has gone mainstream. Unlike most other diet plans, the technique focuses not on what you eat but on when you eat. According to Healthline, some of the most popular types of intermittent fasting include the 16/8 method (eating only within an eight-hour window), the 5:2 diet (limiting how many calories you consume two days per week), and 24-hour fasts once or twice a week.

With multiple options to choose from, it's no wonder intermittent fasting is one of the most popular diets in the U.S. According to a 2020 YouGov America survey found that 24% of adults have tried fasting, beating out plans like Weight Watchers and the keto diet.

Though fasting is fairly straightforward and offers some flexibility, is it healthy? Glam turned to Mary Sabat, a nutritionist and ACE-certified trainer, to find out what benefits you can expect by limiting when you eat.

When you bump your knee or cut your finger, you may notice some redness and swelling after. This is the body's natural inflammatory response to protect itself from invaders like bacteria and viruses. However, Cleveland Clinic notes that when inflammation is long-lasting, it may cause chronic pain, fatigue, rashes, and other symptoms.

Your body isn't meant to constantly fight off potential threats with inflammation. One way to reduce inflammation is by fasting, explains Mary Sabat. "Studies have found that fasting can reduce inflammation by reducing the production of inflammatory cytokines and increasing the production of anti-inflammatory cytokines," Sabat says. "In addition, fasting can reduce oxidative stress, which is also associated with inflammation. Fasting can also help reduce levels of free radicals, which can cause inflammation."

Sabat also reveals that fasting can keep inflammation under control by reducing glucose and insulin in the bloodstream, which in turn may also lower your chances of developing type 2 diabetes (an inflammatory condition in itself), per Medical News Today.

You may have heard a friend or TikTok influencer touting the cognitive benefits of fasting, and according to Mary Sabat, there's truth to these claims. "Fasting can have a positive impact on mental clarity by reducing inflammation and improving focus," she says. "As levels of cytokines decrease [through fasting], mental clarity can be enhanced, and the brain can become more focused and alert. Furthermore, fasting can reduce the amount of glucose in the bloodstream, which can improve concentration and help to reduce fatigue. Fasting has also been linked to increases in neurons, which can lead to improved cognitive functions such as memory and learning."

If a sharper mind is what you're after and your pre-work breakfast only seems to make you feel worse, try waiting longer before having your first meal, or consider shortening your eating window for the day. But keep in mind that poor concentration can also be a side effect of fasting, according to Mayo Clinic. Thankfully, you can typically expect brain fog to improve within a month of starting your fasting plan.

If you've tried to shed a few pounds at some point, you're not alone. Data from YouGov suggests that over half of adults worldwide are regularly trying to lose weight. And while there are a dizzying number of crash diets to try, many aren't all that effective. Fasting, explains Mary Sabat, can be a no-nonsense way to meet your weight-loss goals by reducing calorie consumption. "When fasting, the body is forced to use stored energy, such as fat, which is then burned as fuel. This leads to a decrease in overall body fat as well as an increase in metabolism." Sabat also adds that fasting promotes weight loss by controlling insulin levels (high insulin is associated with weight gain, according to a 2017 article published in Current Obesity Reports).

By training your body to follow a different eating pattern, you may also notice that you no longer need that mid-afternoon snack or post-dinner dessert. Sabat says, "Fasting ... helps to reduce food cravings, which prevents overeating and helps maintain a healthy weight."

Forget the mythical fountain of youth. One of the most promising benefits of fasting might just be a longer, healthier life. Mary Sabat tells Glam that fasting induces the body's state of autophagy. "Autophagy is a cellular process in which the body breaks down and recycles damaged cells, improving the quality of our cells and allowing them to remain healthy and functioning for longer," she explains. Think of it as your body's way of doing a deep cleaning to eliminate any junk that might be hampering your health. "This process is believed to slow down the aging process, reduce the risk of diseases, and help our bodies stay healthy for longer."

Per Healthline, autophagy occurs in the body naturally, though the mechanism isn't always as efficient as it could be. Fasting, along with calorie restriction and exercise, are among the few known ways to boost the process and keep your body youthful from the inside out.