How Intermittent Fasting Works
Every time we eat, insulin is released to help burn up the calories we've consumed. After a day of fasting, insulin levels are very low, and this triggers the body to burn stored fat. Fat is broken down into fatty acids that can be used as fuel in the absence of food. Fasting also facilitates the production of growth hormone, an aid in burning fat and gaining muscle. The trick is to fast for 24-48 hours and no longer. Humans are built to withstand periods of little or no food, and the metabolism slows down when fasting continues for more than that amount of time.
Another reason that intermittent fasting works is that you end up consuming fewer calories. Even if you eat more than usual on the days you're not fasting, you certainly won't eat twice as much as usual. The result is a net reduction of calorie consumption. Alternate day fasting eliminates the most calories and can lead to weight loss of up to 1.5 pounds a week. That's well within the safe parameters for weight loss, and it's actually better for you than dropping more than that by other methods. Also, people who lose weight gradually like this are more likely to keep the weight off.
Lose Fat, Not Muscle
A significant risk when trying to lose weight is muscle loss. Simply cutting calories doesn't trigger your body to burn fat the way low-carbohydrate eating and intermittent fasting do. Using intermittent fasting as a weight loss strategy gets rid of weight more slowly than restricting calories every day, but studies have shown that a significantly lower percentage of muscle tissue is lost.
Types of Fasting
The decision of which method of intermittent fasting to use is a personal one. The most important thing is to choose a plan that you can stay with for the long run. If you can get through the fasting periods, your reward is being able to eat normally in-between. The quality of the food you eat still counts, but you don't have to feel deprived like you would with permanent calorie restriction. Pay attention to calories, although it's not necessary to count them, and stick to whole foods and healthy choices as much as possible.
You can have as many calorie-free beverages as you like during fasting periods. Water is always a good choice, and coffee and tea without sugar are also acceptable. For many reasons, diet drinks with artificial sweeteners should be consumed in moderation or not at all. Here are some popular choices in intermittent fasting eating plans:
16 - 8 Method
There's an eight-hour window for eating each day with this method of intermittent fasting. In that time, you can eat normally and have 2-4 meals if you wish. For the remaining 16 hours, you don't eat. This is a fairly easy way to implement intermittent fasting, since you can have the eating window during your regular daytime hours, such as 10 a.m. to 6 p.m. (My son uses this method of IF)
5 - 2 Method
This plan allows you to eat normally for five days a week. The other two days aren't complete fasting days, but close to it since you restrict calories to 500-600 each day. Weight loss is comparable to a diet that moderately restricts calories on a daily basis, but with the added benefits of intermittent fasting.
This is basically going on a 24 hour fast once or twice a week. Some people begin right after dinner and fast until their normal dinner hour the following day. This eating plan is more difficult to maintain than the other two because it's the only one that involves going without food for a full 24 hours.
Benefits and Drawbacks of Fasting
According to Frank Hu, M.D. from the Harvard T.H. Chan School of Public Health, intermittent fasting can cause positive changes in health. The immune response is activated, and levels of blood lipids and blood sugar are improved, along with blood pressure readings. Inflammation also subsides with intermittent fasting, and there's exciting news that it may increase learning and memory functions in the brain. The downside of attempting weight loss using fasting is that it can be harder to stick to than some traditional weight-loss plans. Also, people may experience light-headedness, fatigue and nausea at first, until they adapt to fasting.
- Helps people eat fewer calories.
- Optimizes hormones.
- Burns fat.
- May help with chronic illness.
- Difficult adjustment period.
- More difficult to maintain.
- Not recommended for those with health issues.
How to Make It Work for You
If you decide to give intermittent fasting a try, remember that you not only want to lose weight, but you also want to do it in a healthy way. That's an important component of any weight-loss plan. Eating high-calorie junk food will make it harder to get through the fasting periods, and sticking to whole foods with complex carbohydrates will make the experience much better. Once you begin losing weight on a regular basis, that will give you motivation to keep going. And when your body starts burning fat for energy, it will help assuage your hunger pangs. You can do this!