Intermittent fasting is surging in popularity; it is one of the top weight loss diets searched on the internet.  Family and friends are buzzing about their experiences and before/after photos are popping-up on social media.  Should you jump on the band wagon? 


What is Intermittent Fasting?

Intermittent fasting is a diet regimen that alternates patterns of fasting and eating.  There are many variations on the theme.  The fasting phase may involve no food or a significant calorie reduction.  The eating phase is often described as eating “normally” or eating “moderately.”  None of the intermittent fasting plans provide nutrition recommendations; the plan is entirely about intermittent energy restriction.


The Three Most Common Plans

1) Periodic fasting (the 5:2 diet): fast or significantly reduce food consumption (500-600 calories) two days and eat regularly on other days.  Example: fasting on Monday/Wednesday or Tuesday/Thursday, eating normally the rest of the week.


2) Alternate day fasting (the eat-stop-eat diet): alternate between eating very little food (500-600 calories) one day, and eating normally the next day.


3) Time-restricted fasting (the 16/8 diet): fasting for a period of 16 hours, and eating normally during a window of 8 hours per day.  Example: fasting from 6pm to 10am, followed by eating from 10am to 6pm.


Fasting and Weight Loss

There is plenty of hype associated with Intermittent Fasting but very little mention about the down side.  Going without food for long periods is very difficult and fasting can be unpleasant, especially at first.  People initially experience hunger, irritability, fatigue, insomnia, and headaches; thankfully, these side effects often resolve over time.  The on-again, off-again eating behaviors can be very disruptive to daily life.  And, when dieters quit very restrictive plans, weight inevitably returns.



The biochemical benefits of fasting in general may prove to be very worthwhile.  We need more research on humans; much of the current research is on mice.  We do know there is great benefit from not overeating.  And providing a period of rest between eating has also proven helpful in several ways. 

  • Reductions in oxidative stress and inflammation – this is a BIG deal; these are the drivers of chronic disease. Fasting also appears to preserve learning and memory functioning.
  • Improved insulin sensitivity – this means your insulin works better and faster. This is a tremendous help in blood glucose management and can slow the progression of pre-diabetes to diabetes.  If you already have Type 2 Diabetes, improving your insulin sensitivity can help you control glucose with less medication.
  • Extended periods of time without eating encourages the body to tap into fat stores which are then burned for energy. This can be beneficial at targeting resistant fat which is often hard to lose.
  • Basically, fasting for periods of time gives your body a rest. We often see reductions in blood pressure, fasting glucose, A1c, and body weight.



When we observe “dieting” we often observe behaviors that are temporary and counterproductive to a healthy, balanced, sensible relationship with food. 


  • Intermittent Fasting may encourage extreme behavior. For example, fasting two days per week or every other day may give license to eat whatever you want on the other days.
  • It may be difficult to follow a fasting plan for a period of time sufficient to achieve the desired weight loss result. And when one eventually abandons the rigors of fasting, the lost weight may quickly return.
  • It is common to designate “cheat days” during a fasting regimen which contributes to a binge eating mentality. This approach does not favor a healthy mindset or a healthy relationship with food.
  • Many people can put the brakes on eating for a time, but when the prior eating pattern resumes, all old habits come crashing down on them.


Talk to your Healthcare Providers

If you would like to try Intermittent Fasting, talk it over with your healthcare providers first.  There may be a need to adjust medications before you begin.  Some Type 2 diabetes medications are contra-indicated during fasting.  There are precautions to discuss with people who have Type 1 diabetes.  A Registered Dietitian Nutritionist (RDN) and/or a Diabetes Care and Education Specialist (CDCES) would have a wealth of information and suggestions to keep you safe.


Middle Ground

Time-restricted fasting (the 16/8 diet) provides many advantages with the fewest disadvantages.  This plan may be the middle ground in the field of fasting. 

  • One benefit of the 16/8 diet over other methods of fasting is that you maintain the routine of eating on a daily basis. Whereas, eating one day and restricting the next day can be very disruptive to your family and lifestyle. 
  • The 16/8 diet may provide a solution to overeating at night. If you refrain from eating after 6:00 pm and eat two or three balanced meals throughout the day, this will mitigate the damage we inflict on ourselves with late-night drinking and snacking, and midnight binges. 
  • There is research suggesting that eating only during daylight hours, related to circadian rhythms, could be beneficial. Your body is best at digesting food when you are active and light is present.
  • Restricting food after 6:00 pm will allow you to get a better night’s sleep, improve fasting blood glucose, provide relief from gastroesophageal reflux, and reduce caloric intake.


Is Intermittent Fasting for You? 

Here are a few more things to consider:

If your focus is primarily on when you eat, will you lose focus on what you eat?  In the long run, our goal is not just to eat less, but also to make better food choices. 


Can you stick with the plan?  Fasting is not a permanent solution for unhealthy eating habits that have led to weight gain.  Most people who have lost weight and kept their weight off have established lifestyle changes and stuck with them.


Eating a little less 7 days per week may prove to be easier than eating a lot less 2-3 days per week.  Following a consistent plan everyday allows you to develop and establish healthy habits.  Perhaps fasting from 6pm to 10am (or 8pm to 12pm) may be a solution to many food problems.