Is intermittent fasting (IF) good for you?
Does it work?
What are some tips for success?
My readers are aware that I have written about diets and nutrition in the past. Our family completed the Whole30 diet in October of 2019 and my wife and I were successful in sticking to the rules for the entire month. The kids couldn’t stick with it. They needed more carbohydrates and got very tired of stir fry’s and curry. Although we aren’t currently eating such a restrictive diet, much was learned during that month with regards to eating and how your body can feel differently when only whole foods are consumed.
Intermittent fasting (IF) was introduced to me by a pharmacist colleague a couple of years ago. He sent me some information via email and I decided to give it a try.
IF is a pattern of normal food intake combined with extended periods where little to no food is consumed. Restricting food intake to a time window of eight hours or less per day is also known as time-restricted feeding (TRF). As you can probably imagine, there are many ways to achieve this.
Alternate Day Fasting
During this plan, you can eat normally on even days and fast on odd days. During your fasting days you may drink non-calorie beverages such as coffee, tea or water. There are many books explaining this method. Probably the most popular is “The Every Other Day Diet” by Krista Varaday. The premise is you can eat all you want, half the time, and lose weight.
The 5:2 Diet
The 5:2 method involves eating normally for five days of the week and consuming only 500-600 calories on two consecutive days after that. I am unable to do this. Eating a few calories makes me hungry.
Lean Gains Protocol
This is also called the 16/8 method. This plan involves restricting your calorie intake to an eight hour period. In my opinion, this is a great place to start. Just pick an eight hour period during the day where you are allowed to eat, and fast for the rest of the day. You could eat from noon until 8:00 PM, for example.
The 20:4 Plan
This is the plan I follow. It is the most restrictive single day fast. This regimen allows for one meal per day. Many find this best for weight loss, ketone production, and mental sharpness. I do not recommend starting here, but you can work your way towards this goal. I suggest starting with the 16/8 method as mentioned above.
There are many more possibilities to choose from. Just google “intermittent fasting” and you will find many ideas. There are also several apps available for the iPhone to help you. Some of these include:
- BodyFast Intermittent Fasting
- Zero-Fasting Tracker
- Simple: Fasting & Meal Tracker
- MyFast Intermittent Fasting
If you own an iPhone and want to try IF, I strongly suggest downloading one of these apps. It makes the process much easier. These apps also contain a ton of useful information on the subject.
I have been an “intermittent faster” my whole life. I very rarely eat breakfast because it tends to make me sluggish and hungry, and I find it causes unwanted GI symptoms, dizziness and increases my sugar cravings.
I have always read that you shouldn’t skip breakfast, but this strategy has never worked for my body. I have started using the intermittent fasting plan during the last couple of years where I only eat during a four hour window on weekdays. I do not do this on weekends because I find it too hard to accomplish.
I decided to write a post about the IFD because I wanted to report the available research to my readers. There are many benefits to this diet and I find it to be an effective method to keep my weight stable.
The Basis For Intermittent Fasting
It is no secret that, as a society, we overeat. Most of us eat at least three meals per day and snacks in between. This often leads to the consumption of too many calories predisposing our bodies to metabolic complications such as excessive visceral fat accumulation and insulin resistance. Lack of exercise makes these conditions even worse. The truth is, we are perfectly capable of surviving by eating less food, less often. There are many ways to practice IF. The benefits of these diets include:
- Depletion or reduction of glycogen stores.
- Mobilization of fatty acids.
- Maintaining blood glucose levels in the low-normal range.
- Reduced leptin and elevation of adiponectin levels.
Behavioral effects are also possible and include increased alertness and improved mental acuity.4
Intermittent Fasting and Diabetes
The popularity of IF has revolved around losing or maintaining weight. This is what initially piqued my interest. It makes sense that if you eat for only a small portion of the day, you will likely consume less calories. Less calories means less weight. There are other benefits, however, which I have listed above. What do the studies say about IF and weight loss?
Most of the studies performed on intermittent fasting and weight loss are done during Ramadan. One such study, published in 2019, looked at the effects of intermittent fasting on individuals with metabolic syndrome (MetS).5
Metabolic syndrome is characterized by insulin resistance, hypertension, abdominal obesity, and poor lipid profiles. Most countries have a 20-30% prevalence of MetS among their adult population.6
It is important to point out that there are three general approaches most commonly investigated in studies of fasting.
- Dietary restriction – One or more macronutrients are restricted with or without a total calorie reduction.
- Intermittent fasting – Whole-day fasting or time-restricted feeding (TRF).
- Daily caloric restriction – cutting 20-40% of daily caloric intake.
The 2019 study cited above showed a significant positive association between weight loss and the number of fasting days. The reduction of fat and body weight were achieved during the Ramadan fast while retaining lean mass. The non-fasting group showed no changes in weight. The fasting group experienced a decrease in both daily calorie intake, and physical activity. This led to a weight loss of 1.5 kg. This loss was 76% fat mass, 17% body fluid loss, and only 6% protein loss. The loss of body fat occurring in this study is higher than that reported from calorie restriction alone.7
A meta-analysis was published in February of 2018 reviewing intermittent fasting interventions for treatment of overweight and obese adults.8
This analysis included 400 subjects ranging in age from 37 years to 49 years. All participants were overweight or obese with a BMI range of (26.0 kg/m2 to 35.6 kg/m2). The studies contained in this analysis used different methods of IF. All but one study used self-reporting through food diaries to monitor compliance to the various protocols.
This meta-analysis found that intermittent fasting is as effective as the current clinical practice utilized for weight loss in overweight and obese individuals. Only a few studies met criteria to be included in this analysis, and most participants were women. These studies were of short duration and follow-up was very poor. Compliance was measured almost exclusively by diaries obtained by the subjects. Due to these issues, the researchers concluded that there was insufficient evidence at this time to recommend routine use of IF for weight loss in overweight and obese individuals. I did consult my personal physician and his take was that IF likely not cause harm and may indeed lead to weight loss. He stated that many of his patients utilize IF, especially athletes.
What to Drink During Fasting Periods
A common question people ask is “what can I drink during the fasting period?” My suggestions are listed below. If you ask several people about this, you will get many different answers. Always remember that no two people are the same. Find a plan that works for you and stick to it!
1. Water – This is my number one choice. Water is very good for your body and you need to remain hydrated. You should drink plenty of water daily whether or not you are fasting. You may add lemon slices to the water if you desire.
2. Bulletproof Coffee – This is one of my favorites. There are different ways to make this but I just use black coffee and add MCT oil to it. Others use butter and some add butter and MCT oil. The MCT oil I use is pictured below. I only drink one cup of coffee per day that contains one tablespoonful of MCT oil because the oil contains saturated fat. This special coffee helps curb hunger. You can also try one of our keto supplements if you find you are getting hungry or are low on energy.
3. Apple Cider Vinegar – I occasionally add 1-2 tablespoons of apple cider vinegar to my water for taste and health reasons. I wrote an entire article on this. Click the link above to read more about the benefits.
4. Tea – Tea is fair game as long as you don’t add sugar. I also advise against artificial sweeteners (see below.)
Intermittent Fasting and Artificial Sweeteners
I do not recommend using any artificial sweeteners during IF. These products are not good for your body and, in many cases, can cause sugar cravings. This means no diet sodas or sweet coffee. At least one study showed that these substances actually lead to glucose intolerance by altering the intestinal micro biota.9
If you must utilize artificial sweeteners, I recommend Stevia. I just prefer the brand you use does not contain glucose or sugar alcohols.
Risks of Intermittent Fasting
- Dehydration. Be sure to hydrate especially during your fasting periods10
2. Increased afternoon urine osmolality.
This can also be avoided by adequate hydration. Remember to drink plenty of water during the day.11
3. Increased cortisol levels.
Fasting causes stress to our bodies. This leads to a release of cortisol which is our primary stress hormone. This may lead to an increase in fat storage although, as stated above, studies show that IF actually decreases fat.12
4. Increased guilt.
Inability to stick to the fasting regimen may cause one to feel guilty. I don’t put much stake in this as any diet may have this effect.
5. Decreased alertness.
Even though IF is known to improve alertness and concentration in the short term, it is possible that if enough calories are not consumed, one may actually become less alert and fatigued. Dizziness may also result. This can be easily rectified by simply eating more calories during your eating window.
I have been using the 20:4 intermittent fasting plan off and on for a couple of years. For me it was a fairly easy transition as I rarely eat breakfast. I just had to train myself to skip lunch. It was difficult at first, but I found the bulletproof coffee and drinking a lot of water helped me get through the day. I also only do this during the work week so I eat whatever I desire on weekends. I do not lose weight on this diet unless I am exercising regularly, but I don’t gain weight, either. It is a perfect solution for me.
My recommendation is to also check with a physician prior to initiating a diet, especially if you have diabetes or take medications. You should have routine check-ups with your physician and you may discuss diets at that time. Although IF is not for everyone, I do believe it can help most people achieve weight loss safely.
Some other pointers are:
- Be sure to have healthy food available to eat during your feeding period. You do not want to fill up on junk food and empty calories.
- Stay hydrated. Drinking plenty of water will help you feel less hungry and keep you from getting headaches and becoming lethargic.
- Have a plan. Try different approaches to IF and pick the one that is right for you. Remember, we are all different.
- Utilize an iPhone IF app. There are many to choose from. These apps are great for tracking your food intake, weight, and they contain valuable information to help you succeed.
I hope you have gained something positive from this post. My goal is always to help my readers live a happy, healthy life. If you have any topics you would like covered or have any questions for me, please reach out by email. I am always here to help.
Have a great week!
Michael J. Brown, RPh, BCPS, BCPP
Mr. Brown is a Clinical Pharmacist specializing in pharmacotherapy and psychiatry.
Feel free to send Michael a message using this link.
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- Harris, L., Hamilton, S., Azevedo, L.B., Olajide, J., Brún, C.D., Waller, G., Whittaker, V.J., Sharp, T., Lean, M.E., Hankey, C., & Ells, L.J. (2018). Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database of Systematic Reviews and Implementation Reports, 16, 507–547.
- Suez J, Korem T, Zeevi D, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014;514(7521):181–186. doi:10.1038/nature13793.
- Trabelsi K, Rebai H, El-Abed K, et al. Effect of ramadan fasting on body water status markers after a rugby sevens match. Asian J Sports Med. 2011;2(3):186Y194.
- Cheah SH, Ch’ng SL, Husain R, Duncan MT. Effects of fasting during Ramadan on urinary excretion in Malaysian Muslims. Br J Nutr. 1990;63(2):329Y337.
- Roky R, Houti I, Moussamih S, Qotbi S, Aadil N: Physiological and Chronobiological Changes during Ramadan Intermittent Fasting. Ann Nutr Metab 2004;48:296-303. doi: 10.1159/000081076.
