What is intermittent fasting?

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COLUMBIA - What the heck is intermittent fasting? The simplest definition is that intermittent fasting is a pattern of eating where you make the conscious decision to skip certain meals, then eating at other times.

There are different versions of intermittent fasting. One version is to eat only 500 calories on your fasting days and then eat whatever you want on your feasting days. (I know, it sounds counterintuitive in a way.) Another way is to fast for 14-16 hours every day and the only eat meals during the remaining hours (i.e. you would only eat between 9am - 5pm). 

Prevention magazine did an article on intermittent fasting and the author stated these benefits to fasting:

  1. You burn more fat: If you go without food for six hours or more, your body starts burning fat for fuel. That's probably why researchers at the University of Illinois have found that people who fast every other day lose 90% or more of their weight from fat stores on your thighs and hips. The fat loss is a good 15% higher than what people attain on traditional, diet-every-day plans.
  2. You retain more muscle: Anytime you shed pounds through dieting, you lose a combination of fat and muscle. But with fasting (at least when you do it every other day) you lose less muscle. That matters because your muscle dictates your metabolism.
  3. You control your blood sugar: A number of studies on intermittent fasting have shown that it increases the body's sensitivity to insulin, the hormone that regulates blood sugar.
  4. You protect your brain: The National Institute on Aging has discovered that periodic fasting protects brain cells from routine damage.
  5. You help your heart: Fasting reduces your risk of heart disease by lowering cholesterol, triglycerides and blood pressure, according to a number of studies.
  6. You shed belly fat: A 2012 study by researchers at the University of Illinois found that after eight weeks of alternate-day fasting, participants lost three inches from their waists, regardless of whether they consumed a high-fat or low-fat diet on their feast days.


Now that you understand the benefits of intermittent fasting, let’s look at a few different methods. (Maybe you’ll find one that you want to try…)

16/8 or Leangains: This method involves a 16-hour fasting window and an eight-hour feasting window. An example would be to stop eating at 7:00 p.m. and then fast until 11:00 a.m. the next day. During the feeding window, two to three meals are consumed, consisting of healthy, whole foods. There are specific guidelines about what to eat.

To consider: You will skip breakfast and have lunch as your first meal. Keep in mind, if you’re someone who needs to eat in the morning in order to function or if you do early morning workout, this might not work well for you.

5:2 or Fast Diet: Twice a week (nonconsecutive days) you restrict calories to around 500 calories a day (600 calories for men), and for the other five days you eat as if you are not on a diet. You can eat three small meals or two slightly larger meals (lunch and dinner).

To consider: There are no restrictions on what you can eat on regular days, and you can choose which days to fast based on your schedule. However, not eating very much for a whole day can be really tough (especially if you work, exercise or have a family to prepare food for).

Eat, Stop, Eat: This method involves fasting for 24 hours once or twice a week. Simple.

To consider: You only restrict your calorie intake once or twice a week, then eat however you want the rest of the time. However, not eating for a full 24 hours is tough. Also, only restricting your calories once or twice a week may not result in much weight loss.

The Warrior Diet: You fast for 20 hours each day then eat one large meal every night.

To consider: Raw fruits and veggies, fresh juice, and a few servings of protein, if desired, are allowed during the fasting window. The strict guidelines about what to eat for the large evening meal can be hard to follow, and some folks don't like eating a large meal at night.

Alternate Day Fasting or UpDayDown Day Diet: You eat very little one day (one-fifth your normal daily calorie intake), then the next day eat your normal daily calorie intake. Repeat. (For example, on fasting days, you eat 400 calories, and on nonfasting days, you eat 2,000 calories.)

To consider: Cutting this many calories per week results in weight loss. However, you may find it too strict for your schedule to fast every other day. Or you might find it hard to stick to the lower amount of calories on fasting days.

If you are interested in intermittent fasting, I would recommend that you discuss the topic with your doctor first. Especially if you have any medical conditions or take any medications that could be affected.