Most weight loss plans involve tracking what you eat and counting calories. But in the past decade or so, it’s become clear that when you eat may be just as important as what you eat.
Fasting between meals or restricting the time that you eat each day is proving to be beneficial in more ways than one. This approach, known as intermittent fasting (IF), works as a method for weight loss, but it may also benefit your heart, mind and overall health.
Here’s what you need to know when considering whether IF is right for you:
What is intermittent fasting?
IF is a plan for eating that involves eating only during specific times – you choose regular time periods to eat and fast. Fasting on either a daily or weekly basis helps your body burn fat.
There are different approaches to intermittent fasting but the most popular include:
- Alternate day fasting includes normal eating every other day, with days of restricted eating (500 calories) in between.
- Daily time-restricted eating limits eating to one period (typically six to eight hours) each day. The rest of the time, you’re fasting.
- 5:2 approach involves normal eating five days a week, but limiting yourself to 500 to 600 calories for two non-consecutive days.
While there are no hard-and-fast rules regarding what you can consume during your unrestricted eating periods, experts agree that maintaining a healthy, well-rounded diet produces the best results. During fasting times, limit yourself to water and zero-calorie drinks.
How does intermittent fasting work?
Fasting changes where your body gets its energy. Typically, your energy comes from sugar. If you eat constantly while awake and don’t exercise, your body simply runs on the calories you consume. If you don’t use all the sugar you take in during the day, your body stores it as fat.
When you go hours without eating, your body eventually runs out of stored sugar to use. Instead, it begins to burn fat to produce energy.
Health benefits of intermittent fasting
Researchers have studied IF for decades, testing animals and humans to gather evidence of health benefits. More research is needed, especially to determine the advantages of practicing IF long-term. But experts do know that fasting improves metabolism and lowers blood sugar, benefitting a wide range of health issues.
Evidence shows that when you consistently practice intermittent fasting, it may:
- Banish brain fog, by forcing you to get energy from stored fat (a process called ketosis) instead of sugar
- Decrease your risk for diabetes, by controlling blood sugar and reducing your body’s resistance to insulin, the hormone that helps control the amount of sugar in the blood
- Help you lose weight and visceral fat, the harmful fat around the abdomen that causes disease
- Improve sleep, by regulating your circadian rhythm (internal clock) and moving digestion earlier in the day
- Protect your heart, by reducing blood pressure and improving cholesterol levels
- Reduce inflammation, which can improve conditions such as arthritis, multiple sclerosis and asthma
Intermittent fasting tips
While keeping an eye on the clock may be easier than counting calories, it still requires an adjustment. It can take two to four weeks for your body to become accustomed to the new eating schedule. In that time, it’s normal to feel hungry or grouchy, but if you experience unusual anxiety, nausea, headaches or other symptoms, stop IF and speak with your doctor.
To help you make IF a success, follow this guidance:
- Always check with your primary care provider before starting any restrictive eating plan.
- Be active throughout the day to build muscle tone and burn fat.
- Don’t make your fasting period too long (24 hours or longer) because if your body thinks it’s in starvation mode, you may start storing fat instead of burning it.
- Don’t deprive yourself of water and zero-calorie drinks (such as tea and black coffee), which are permitted while fasting.
- Make your eating window earlier in the day, not in the evening before bed.
- Stick with healthy eating and consider a plant-based or Mediterranean-style diet.
Who should avoid intermittent fasting?
Some people should avoid intermittent fasting unless under the close supervision of a physician. Those people include:
- Children and teens under 18
- People with advanced diabetes, or on medication for diabetes
- People with a history of eating disorders, such as anorexia or bulimia
- Pregnant or breastfeeding women
Talk to your primary care physician to see if intermittent fasting is a healthy choice for you.
