Dietitian Reviews Intermittent Fasting
Intermittent fasting is all the rage right now. Although fasting as a whole is nothing new, intermittent fasting as a diet has been gaining momentum and it is a “lifestyle” that I frequently get asked about.
Intermittent fasting is claimed to have many benefits, including weight loss, improved blood sugar control, and decreased binge eating. But is there any truth to these claims?
Table of contents:
What is intermittent fasting?
Intermittent fasting is an umbrella term for periods of fasting and eating. Intermittent fasters only consume food and calorie-containing beverages at particular parts of the day. Intermittent fasting dictates when you eat and not necessarily what you are able to eat, which is different from many other diets that restrict the types of foods that are allowed. However, many people who do intermittent fasting also follow other diet rules (such as keto, “clean eating”, etc.).
Types of intermittent fasting
There are various popular methods of intermittent fasting, including:
The 16/8 Method: This method encourages 16 hours of fasting and allows for an 8 hour eating window. The eating window depends on your job, physical activity, and other lifestyle factors. Many intermittent fasters prefer a noon to 8 pm eating window so that breakfast is the only fasted meal. Others may prefer a 9 am - 5 pm eating window, allowing for a breakfast, lunch, and early dinner.
Eat-Stop-Eat: The Eat-Stop-Eat method involves fasting for 24 hours 1-2 times each week. This might look like eating breakfast at 7 am as the only meal of the day and then breaking the fast the next day at 7 am.
The 5:2 Method: This method involves eating as you normally would for 5 days of the week and then eating around 500-600 calories for 2 days of the week.
Does intermittent fasting have any health benefits?
Intermittent fasting and weight loss
Will fasting help you lose weight? In the infamous words of every dietitian on every topic ever - it depends.
Because intermittent fasting decreases the period of time in which you are allowed to eat, some people eat less than they normally would. This puts them in a caloric deficit and weight loss is the result. This logic is the same as any other diet except for intermittent fasting restricts when you eat rather than what or how much you eat (depending on the method that you do).
But here is the big issue with intermittent fasting (and any other diet) - once you become burnt out from feeling restricted, you will likely return to old habits and regain weight that was lost (and possibly more). This is not a failure on your part. This is what dieting sets us up to do. If you are looking for a method of pursuing health that doesn’t involve dieting and micromanaging your weight, I recommend this post as a starting point.
Intermittent fasting and GERD
@dietitianhannah Replying to @auntieimhungry gee, if only we’d thought of that! #dietculture #dietitian #dietitiansoftiktok #foodfreedom #ditchthediet #intermittentfasting #dietsdontwork #intuitiveeating #dietitianhannah ♬ original sound - Dietitian Hannah
Intermittent fasting may help with gastroesophageal disease (GERD), depending on when an individual’s fasting period is. For some individuals, eating too close to bed can lead to acid reflux if they eat and then lay down shortly after. If you experience any sleep disturbances eating too close to bed time, it may help to stop eating a couple hours before you go to sleep. However, I would not necessarily classify this as intermittent fasting, but rather just eating in a pattern that makes you feel good.
Intermittent fasting and binge eating
Some individuals claim that intermittent fasting has helped them overcome binge eating by creating strict rules around when they are “allowed” to eat. While this may helpful for some, many others find that such restriction makes their binge eating worse.
Binge eating can occur for so many reasons, but a common denominator tends to be restriction (either physical or mental). Our bodies have compensatory mechanisms in place for when we diet and limit our food intake. When you do not give your body the fuel that it needs, it will work hard to make sure that you do. For some intermittent fasters, this shows up in the form of binge eating after a 16+ hour fast.
Learn more about how intuitive eating may help with binge eating by reading this post.
Who should not do intermittent fasting?
Anyone with a history of eating disorders or disordered eating
@dietitianhannah All in the name of health, right? 🤪 #intermittentfasting #bedrecovery #fasting #foodfreedom #dietculture #ditchthediet #dietitiansoftiktok #dietitianhannah #dietitiantips #nutritiontips ♬ original sound - bella
At the end of the day, intermittent fasting is a restrictive diet. Restriction is a known trigger for disordered eating habits. When we ignore our internal cues to eat because of food rules, such as arbitrary times that we are not “allowed” to eat, this can lead to getting caught up in the restrict/binge cycle.
If you have a history of disordered eating or an eating disorder (including binge eating disorder), I recommend staying far away from intermittent fasting.
Anyone with a physically active job
If your job is physically demanding and requires regular calories for energy throughout the day, intermittent fasting is probably not a good fit. We get our energy from food and if you are fasting and not able to eat, this will likely impact your job performance.
It is also worth noting that coffee is not a meal and I do not recommend using caffeine for energy instead of food.
Individuals with diabetes
Blood glucose stability is important for everyone, but it is even more crucial for people with diabetes. Fasting may lead to hypoglycemic episodes (low blood sugars), which can be dangerous. It is encouraged that individuals with diabetes do not go longer than 5-6 hours between meals/snacks. Ideally, I would recommend eating every 3-4 hours for optimal blood glucose management and including carbohydrates, protein, and fats at each feeding time.
Bottom line
Intermittent fasting is just another diet and way to restrict calories. That’s all there is to it. I would not recommend it for most people because I believe that any diet that has strict rules and makes you go against your hunger and satisfaction cues is one that isn’t going to be beneficial to your physical or mental health.
That being said, I get comments frequently from people telling me that intermittent fasting works for them. If that is the case and you can stick to it long term, then godspeed.
