It’s a little controversial, but when done the right way (with doctor supervision), fasting may deliver powerful health benefits.

What about intermittent fasting? Does it provide benefits to the brain and body, or is it harmful? Let’s take a look.

Spotlight On Diet: What Is Intermittent Fasting?

Intermittent fasting is just like it sounds. You alternate periods of eating with periods of not eating. There are a few different ways to go about intermittent fasting. Here are two of the more popular methods.

Alternate-Day Intermittent Fasting

This simply means eating some days and fasting other days. On the days where you fast, you aren’t supposed to consume any sort of foods – or even beverages – that contain calories. You can have drinks such as tea, water, or black coffee, as long as they don’t have any calories (so skip the sugar and cream in your coffee or tea).

If you’re on a diet that follows an alternate-day intermittent fasting routine, eating is obviously encouraged on your non-fasting day. As long as you follow a healthy diet, you can eat just about as much as you want. The purpose of this type of intermittent fasting plan is to cut your calorie intake over the long run, thus supporting your weight loss goals.

According to research, the alternate-day method is somewhat similar to a regular low-calorie weight loss plan in terms of effectiveness. But it can be a challenging way to diet for some. You could experience serious bouts of hunger on non-eating days, of course. This may also affect your ability to concentrate.1

Modified Intermittent Fasting

Vegetable BrothModified intermittent fasting typically means that you eat every day – just very little. It’s not like alternate-day fasting, where you go without any calories whatsoever on certain days.

The 18:6 fasting plan is a very common type of modified intermittent fasting. As the name implies, you don’t eat for 18 hours after the last meal of the day. This meal should be no sooner than three hours before you go to bed. When your six-hour eating window arrives, you can have two or three meals.

You don’t have to go without anything during the 18 hours, however. You can have vegetable or chicken broth, as well as water, coffee or green tea. During the other six hours, you should eat healthy foods such as vegetables, lean protein, and fruits.2

The 5:2 Plan

An additional type of modified fasting is known as the 5:2 plan. This simply means you fast two days a week – eating nothing on these days – and then you eat normally the other five days during the week.3

The jury is still out as far as whether modified fasting works. Some people who participated in studies reported greater weight loss than on a typical diet plan. Others report that their results weren’t that substantial. Yet others report no difference at all between modified fasting and a diet consisting of reduced calories.4

How Might Intermittent Fasting Provide Benefits?

Sugar in BloodIntermittent fasting has been shown to have positive effects on insulin resistance and may support healthy blood sugar levels.
Insulin resistance is where the body ignores the signs to release glucose for energy. As a result, the pancreas makes more insulin. Over time, the pancreas works so hard that it can’t produce insulin anymore. This can cause blood sugar levels to spike, leading to severe health problems and weight gain.5

In addition, intermittent fasting also allows the gastrointestinal tract to rest. The body can then use the fat in cells as fuel rather than the food you would normally eat.6

Research indicates that one of the potential benefits of fasting is a possible increase in the amount of human growth hormone in the blood.7 This can not only support weight loss but may also help to increase muscle.8,9

There is also evidence that fasting could benefit many of the genes and molecules that contribute to helping you live a longer, healthier life.10,11

Intermittent fasting may also support heart health.12

Are There Any Risks Associated With Intermittent Fasting?

There may be some potential risks to fasting, however. For example, Intermittent fasting might disrupt the circadian rhythm. This is a sort of “internal clock” that tells you when you need to go to sleep.

Trouble sleepingResearch indicates that fasting can also affect the quality of your sleep, specifically REM (rapid eye movement) sleep. This is the type of sleep that is associated with your ability to learn as well as your mood.13

Taking the quality of your sleep seriously is important. If your sleep is disturbed, that can affect your brain in negative ways. You could experience brain fog, which could really impact the quality of your waking hours.14

Some other potential side effects of fasting could include mood changes and dizziness. If you are pregnant, take medicines that require food, or if you’ve experienced eating disorders in the past, your doctor may suggest another method for supporting your weight loss goals.15

Considering Fasting? Talk With Your Primary Care Physician First

It’s important that you never try any sort of diet – whether it involves intermittent fasting or some other type of weight loss program – without first talking to your doctor. Your doctor can discuss the benefits and risks that may be associated with fasting and help you determine which type of plan is the safest for you.