What Science Has Proven About Intermittent Fasting (And What it Hasn’t Figured Out Yet)

Intermittent fasting has taken off over the last few years, and science has been paying attention. That said, it’s important to recognize that the research is ongoing, and our understanding of this practice is far from complete in terms of both its benefits and drawbacks.  Therefore, it’s very important to be careful to check the sources of your information before you choose to believe them.

What Science Tells Us About Intermittent Fasting

Research surrounding intermittent fasting (IF) is quite promising. That said, it’s important to recognize two very important points about the science so far. The first is that it has primarily been conducted on rats.  The second is that IF is not just one practice, but is instead a style of eating, and the timing of this practice has a massive impact on its outcomes.

Research has shown that timing is exceptionally important to the potential health benefits of intermittent fasting, but it can also determine its shortcomings. For instance, a well-timed IF strategy can support weight loss, cholesterol, blood pressure and even blood sugar goals. However, when done with the wrong timing, it can be too difficult to be sustainable, negating the benefits.

How Can IF Help Your Weight Loss?

Intermittent fasting may be helpful for weight loss, provided that the timing can be accomplished appropriately for sustainability and to avoid the inclination for binging. Overall, the benefit to IF isn’t that it helps you to eat fewer calories.  When practiced well, the same healthy calorie range should still be the target.  What makes this technique more beneficial than spreading those same calories out throughout a longer period of time is that your insulin levels will remain lower for a longer and steadier amount of time – while you’re not eating – causing your body to turn to stored fat as a fuel source.

How to Use Intermittent Fasting Sustainably

There are lots of IF strategies out there which tell you to skip certain blocks of time every day, or even entire days of the week. These are not necessarily your most effective strategy, says research cited by Harvard Medical. All IF approaches are not the same in terms of effectiveness, ease or sustainability.

That said, when compared with a healthy eating strategy such as Mediterranean Diet-style meals, synching eating with the circadian rhythm can not only support easier weight loss and nighttime sleep but can also reduce the risk of diabetes or obesity.

A University of Alabama study involved the participation of a small group of obese men who all had prediabetes. They were divided into two groups. The first was required to eat all their meals between the 8-hour span of 7 am to 3 pm.  The second had a 12-hour span from 7 am to 7 pm. Both groups maintained their body weight, experiencing neither weight loss nor weight gain. However, after 5 weeks, the group with the 8-hour eating restriction had significantly lower blood pressure and insulin. Moreover, that group’s appetite had measurably decreased. This suggests that by changing meal timing, it would be easier to lose weight if following a Mediterranean-style or calorie restricted diet. 

Shifting the times alone didn’t cause weight loss but as the intermittent fasting was followed for a while, it did build a foundation that would make it easier to lose weight through dietary changes.

Dietary Changes to Pair with IF

The Harvard Medical report recommended pairing the following with intermittent fasting to achieve desirable health results.

1. Avoiding added sugars and refined grains, in favor of fruits, veggies, beans, lentils, whole grains, healthy fats and proteins such as in a Mediterranean-style diet.
2. Give the body the chance to burn fat. Be active throughout the day, build lean muscle, and avoid grazing on food all day long so that the insulin levels have the chance to fall.
3. Consider simple intermittent fasting if appropriate for you. Speak with your doctor first, to ensure that this is safe for you, as it is not appropriate for everyone. Then, see if you can find a way to reduce the number of hours in which you’re eating. Ideally, draw it back to an 8-hour window per day, but simply avoiding eating overnight can be a great start.
4. Avoid snacking in the evening or overnight. Have a good dinner, then drink water or a decaf/non-caffeinated tea for the rest of the evening.  Avoid pop (even zero-calorie), juice and other sweetened beverages that contain calories, sugars or other substances that cause your insulin levels to alter. Focus on staying hydrated and build the habit of stopping evening snacking. It may be tough at first, but your body will adapt, and it will become easier. This will automatically increase your body’s fasting time every day.