Intermittent fasting has garnered a cult-like following among fitness and health enthusiasts in recent years and it’s fair to say that this has led to a few misconceptions about what intermittent fasting (IF) actually is and what the ramifications of it are. It’s not surprising that the intermittent fasting lifestyle has about as many haters as it does advocates, but that is usually just a sign that there is indeed some sound reasoning behind it.
Rather than write the umpteenth article praising the benefits of intermittent fasting diets, this article will instead look at some common unfounded claims about the detrimental effects of intermittent fasting and provide rebuttal to the idea that it is an unhealthy way of eating/living (and before we move on, know that I’m not saying that intermittent fasting is the holy grail for everyone and superior to any other style of dieting, but just that the suppositions to be discussed are rather baseless if you’re following intermittent fasting properly).
Misconception #1: Intermittent fasting has limited uses in limited populations
I actually have to chuckle a bit about this claim since I would argue the contrary about intermittent fasting; that is to say that intermittent fasting is probably more applicable to the majority of people’s lifestyle than eating around the clock. In fact, the majority of people who follow an intermittent fasting lifestyle find that the relief from obsessively following the clock all day to make sure they are eating every few hours is one of the biggest psychological benefits.
Continuing on, let’s think about the average American’s (and most other First World nations) daily routine: wake up, rush out the door to work/school, sit in the office/classroom until late afternoon (maybe eat lunch), come home after a long day, eat a big dinner, enjoy some downtime and probably eat another meal before bed. Notice that breakfast is often overlooked to begin with? Many people are just more preoccupied with making sure they are clean and ready to go for the day then they are concerned about eating in the morning.
The last argument in favor of intermittent fasting in this case is that not many people are very fond of eating a large meal in the morning and/or in the middle of a school/work day, unless you like carrying on with your day feeling like a rock is in your stomach and enjoy moving your bowels in public facilities (alright the latter argument is pretty out there, but you get the point).
The gist of it is that for many people it’s just more convenient to go about the early (and often mid) part of their day without worrying about food and coming home to eat a nice dinner with the family and relax a bit. Again, this isn’t to say frequent feeding doesn’t apply to anybody, but just that the supposition that intermittent fasting has limited uses in limited populations is quite inane if you think about it pragmatically.
Misconception #2: Intermittent fasting leads to glorified bulimia and binge eating disorder
This claim is also somewhat laughable in that it blankets intermittent fasting into a category of “disordered eating” while on the other end of the spectrum people who watch the clock and eat exactly every 2.706660193 hours are inherently the “normal eaters” of this world. Frankly, I don’t care if you eat two meals a day or ten meals a day, as long as you’re meeting your calorie and macronutrient goals then that right there tells me you are able to stick to your diet; the timing and quantity of meals is secondary.
Moreover, to say that fasting and then eating a large meal is a form of glorified bulimia and binge eating is asinine. Fasting has a multitude of health benefits and to say that it is bulimic behavior is just flat out wrong; essentially this would infer that early hunter-gatherer humans were all bulimic, hmmm…Not sure about the veracity of that one.
And what would one expect intermittent fasting advocates do when they start eating? Eat a few raisins and call it a day? Of course intermittent fasters are going to have bigger meals, pretty simple equation really: less meal frequency means more nutrients per meal. Eating a large meal does not equal binging; binging is uncontrolled gluttony. Eating a big dinner within your nutrient needs (after a period of fasting) in a controlled manner is perfectly sane, normal behavior.
Misconception #3: Eating big meals with lots of carbohydrates in the evening leads to fat gain
Most bodybuilders and fitness aficionados intuitively tie carbs to insulin, which is correct, but they also tend to overgeneralize insulin’s physiological effects and fear that any insulin release in the evening will turn nutrients into fat since insulin sensitivity is generally lower at night and highest in the morning.
So the theory sounds good on paper, but it falls short in the real world. In fact, a study published in the Singapore Journal of Medicine found that Muslim women actually lost body-fat and bodyweight during Ramadan (1 large meal after sunset and a small meal before sunrise).
Moreover, there are a medley of studies that show little significant difference between carbohydrate oxidation rate in individuals who eat a big meal in the morning versus those who ate an equivalent meal later in the day. [2,3]
And last but not least, there is little reason to believe you would gain fat in the absence of excess energy consumption, so that right there is one reason this claim about carbs at night making one fat is wildly shortsighted.
Misconception #4: Intermittent fasting will lead to muscle loss
The reality is that just because you’re not eating food, especially protein, frequently doesn’t necessarily mean you’re body is in “catabolic” mode like many people seem to think. This idea that fasting will breakdown muscle tissue for energy seems to arise from the idea that the body needs a constant supply of amino acids in order to repair/maintain/build muscle tissue.
What flies over most people’s heads in the context of intermittent fasting is that a large bolus of protein (especially slower digesting proteins like casein) from the last meal prior to a 16-20 hour fast would likely still be releasing amino acids by the time you broke the fast again. In the context of intermittent fasting, it isn’t uncommon for someone to have a complete meal with 100+ grams of slow-digesting protein before they start fasting again.
The thing to keep in mind here is that extended periods of fasting certainly would cause some muscle loss due to de novo gluconeogenesis kicking in after liver glycogen and amino acids are depleted, however for people on intermittent fasting who generally eat a large, balanced meal before fasting again, neither of these situations are likely to occur in 16-20 hours.
Misconception #5: Fasting decreases training performance
The immediate reaction someone has to the idea of fasted training, especially those used to training with a solid pre-workout meal, is usually pulling their hair out in fear of performance decrements in the gym. Well, yet again, the literature on athletes who train in a fasted state doesn’t support the idea that performance is hindered when the body is nutrient-deprived.
For example, a large body of evidence has been provided by studies done on high-level athletes who were training during Ramadan fasting; these studies have repeatedly shown that both anaerobic and aerobic performance are not hampered by intermittent fasting. The other thing to consider here is that intermittent fasting doesn’t advocate abstaining from water/no-calorie liquids during the fasting period, like Ramadan does, so dehydration is not a concern for intermittent fasters.
If you find your performance isn’t up to speed when training fasted, it is likely a psychological/subjective issue that’s causing it. Many people who aren’t adapted to train without eating beforehand give up after a few days of trying fasted training simply because they “feel” weak, hungry, sluggish, etc. If you give your body enough time to adjust though, many of those subjective signals dissipate and you’ll find your performance is back on par.
And lastly, nobody said you have to train fasted on IF to begin with; many intermittent fasters train after a pre-workout meal/shake.
I’m sure many intermittent fasting opponents will look at this article and claim it’s all hogwash, which is fine, you’re entitled to an opinion (*cough* but it’s wrong *cough*…Alright that’s kind of a joke). The reality of intermittent fasting is that when done properly there is little reason to believe it will cause eating disorders, have limited application to people/athletes, decrease muscle mass, increase fat gain, and hinder training performance.
If you’re following an intermittent fasting lifestyle and these aforementioned woes are occurring, then you’re likely doing something haphazardly or being too extreme with your eating/training protocol (e.g. eating once a day, doing hours of cardio on an empty stomach, etc). Take a step back, reconsider a more moderate approach to intermittent fasting, and you’ll be fine.
1) Al-Hourani, H. M., & Atoum, M. F. (2007). Body composition, nutrient intake and physical activity patterns in young women during Ramadan. Singapore medical journal, 48(10), 906.
2) Del Ponte, A., Angelucci, E., Capani, F., Consoli, A., Guagnano, M. T., & Sensi, S. (1984). Modifications in the oscillation of substrates in obese subjects subjected to variations in the pattern of meal-timing]. Bollettino della Società italiana di biologia sperimentale, 60(11), 2099.
3) Sensi, S., & Capani, F. (1987). Chronobiological aspects of weight loss in obesity: effects of different meal timing regimens. Chronobiology international,4(2), 251-261.
4) Chaouachi, A., Leiper, J. B., Chtourou, H., Aziz, A. R., & Chamari, K. (2012). The effects of Ramadan intermittent fasting on athletic performance: recommendations for the maintenance of physical fitness. Journal of sports sciences, 30(sup1), S53-S73.