Intermittent Fasting: Is the latest hot dieting trend good for you?
Does your diet have a curfew? If you practice intermittent fasting, you likely have a firm cut-off time. The practice of eating only within a range of specific hours is gaining a lot of traction among healthy living bloggers and even the mainstream media. While it might seem that everyone is talking about it, you may be wondering if it’s the right choice for you. Let’s chew on some information about the time-restricted eating trend.
What is intermittent fasting?
“Intermittent fasting is when you dedicate certain hours of your day to eating and the other hours to fasting,” says registered INTEGRIS dietitian Brent Wilson. “Fasting is when you do not eat or drink any calorie-containing items. Liquids like water and black coffee are allowed.”
During intermittent fasting, a certain number of hours are allowed for nutritional intake. This is called a compressed eating window. “For example, someone may follow a compressed eating window of eight hours, resulting in 16 hours of fasting,” Wilson says.
A compressed window could open at noon and close at 8 p.m. The window would open and close the same time the following day.
Is intermittent fasting a safe and effective method of losing weight?
Wilson says intermittent fasting can be an effective method for weight loss because people are more likely to reduce their calorie intake when eating during a limited window. “It’s difficult to eat the same number of calories in eight hours compared to the 14-hour eating window that is more aligned with how most people eat,” he says.
Intermittent fasting also aids weight loss by making people more aware of how much and when they eat. “For many people, eating can be mindless and can happen all day long,” Wilson says. “By setting this structured eating window, it naturally raises your awareness of what you consume.”
This could result in healthier eating habits overall. Wilson says that if we don’t put a limit on how much we eat in a day, it can lead to unconscious grazing on unhealthy snacks, even when we’re not hungry. During intermittent fasting, hunger comes on strong and makes it more likely that someone will choose a structured meal that will provide energy for several hours over sugary snacks that provide quick satiation.
Wilson himself practices intermittent fasting regularly and follows research.
“Dr. Satchin Panda is a leading researcher in intermittent fasting and time-restricted eating,” he says. “He states that every cell in the body has a ‘biological clock’ that aligns with the sunrise and sunset. Cells function best when the sun is up and rest more efficiently when the sun is down. During intermittent fasting, our body and digestive cells work best when they aren’t being forced to work outside of their ideal time-frame like late night snacking.”
Pros of intermittent fasting
According to Wilson, a major benefit of intermittent fasting is a process called autophagy. Autophagy is a physiological process that controls the destruction of dysfunctional cells in the body.
“When we fast, our cells take a break from the constant work of digesting and processing food,” Wilson says. “During this break, autophagy allows our cells to do a ‘cellular cleanup’ where the body identifies and destroys unnecessary or dysfunctional cells. This process could be vital in the prevention of disease.”
Intermittent fasting might be a good lifestyle fit for people who often forget to eat. When the eating window is limited, they may be better able to prioritize eating within their time frame and feel less guilty about not fitting in three regular meals during the day.
Cons of intermittent fasting
There is an adjustment period when first starting intermittent fasting. If you’re used to eating three meals or snacking throughout the day, you may struggle with feeling hungry when adjusting to a compressed eating window.
Some people may be tempted to overindulge during their eating window. It’s important to eat well-balanced, nutritional meals and snacks while practicing intermittent fasting to make sure you’re getting essential vitamins and nutrients.
What do I need to know before using intermittent fasting as a weight loss method?
“Intermittent fasting can be extremely challenging at first, especially if you have a long history of eating frequently,” Wilson says. “Most folks are extremely dependent on carbohydrate/sugar-rich snacks to help get them through the day, like granola bars, chips, candy and sugary beverages. I call these people ‘sugar burners’ because they run best when they have an influx of glucose coming into their bloodstream.”
Wilson says once blood sugar drops, it can make people feel lethargic and more tempted to reach for another sugary snack for energy. Wilson challenges clients to stop their sugary snack cycle and reduce their intake of carbohydrates before starting intermittent fasting. He encourages them to consume healthy fats like avocados, nuts, nut butters and proteins. He also recommends non-starch vegetables like broccoli, celery and spinach. These foods provide energy without raising blood sugar levels.
“Once you lose your dependency on carbohydrates to get you through the day, you begin to master the art of using fat as fuel, whether that fat comes from the food you eat or the fat on your hips,” Wilson says.
According to Wilson, this will make the fasting window easier to adjust to as there will be fewer drops in blood sugar. With fewer carbohydrates to burn through, the body will dip into fat stores for energy.
He also recommends that people trying out intermittent fasting should start slow. For first-timers, he recommends a 12-hour window for eating and a 12-hour fasting window. As you progress, you can extend your fasting window to 18 hours. The appropriate fasting time will vary from person to person. Consult your doctor or a dietitian to figure out what’s best for you
Who should avoid intermittent fasting?
Wilson recommends that patients with diabetes who take insulin or other glucose-lowering medications should consult their healthcare provider before beginning intermittent fasting. Pregnant women, people with a history of eating disorders and individuals who are unable to eat only within a limited window due to work or lifestyle constraints should also consult their physician and dietitian before considering intermittent fasting.
Brent Wilson is a registered dietitian with the INTEGRIS Diabetes Education program. He completed the Coordinated Program of Dietetics at the University of Oklahoma Health Sciences Center.