Intermittent Fasting Explained
Like many other fad diets, intermittent fasting is a dietary protocol that has developed a cult-like following. Many of the die-hard fans of this diet claim it to be absolutely superior to any other diet for weight loss. I’ve even seen some gurus say it is the cure for cancer, diabetes, and heart disease; which are undoubtedly some very extreme claims. In this article, I’ll break down what you need to know about intermittent fasting, if it actually works, and if it is right for you.
What is fasting?
We should start off by making sure we have a good understanding of what fasting is. Fasting essentially means not taking in any calories for a prolonged period of time. To be in a fasted state means that there is no more food in your intestines for your body to digest. For most people, it takes about 8 hours to be in a truly fasted state, as food moves through your body more slowly than you might think.
It should be emphasized that fasting specifically is in reference to intake of calories, or energy-containing foods. For example, if you have not eaten anything for 8 hours and you drink a glass of water, you have not broken your fast and are still in a fasted state. However, if you don’t eat for 8 hours and then have a slice of bread, then you have broken your fast. Further, if you drink a cup of black coffee after 8 hours of fasting, you have not broken your fast since black coffee has 0 calories. Alternatively, if your coffee has cream or sugar, then you will have broken your fast.
There are many different forms fasting can take. The most popular form is 16:8 intermittent fasting. This means that for 16 hours of the day you do not eat any food, and you have an 8-hour window of the day in which you are allowed to eat. Some choose to do alternate day fasting, in which one day you eat food as normal and the next day you eat no food at all.
There are also religious customs that call for fasting. For example, the Islamic people practice Ramadan fasting. Where from dawn to dusk they fast. This practice differs slightly from normal intermittent fasting, as they do not drink water during this period either.
How fasting affects the body over time
Over time, there are some legitimate health benefits that can be obtained from intermittent fasting. Research shows that people who intermittent fast tend to decrease their LDL (“bad” cholesterol), increase their HDL (“good” cholesterol), decrease total cholesterol, decrease triglycerides, and more positive health effects.
Further, many people who are overweight and do no change to their diet other than intermittent fasting tend to spontaneously lose weight. This can make it a pretty powerful tool for people who want to lose weight but don’t want to put a ton of effort in.
Is intermittent fasting better than normal dieting?
The health benefits above are the points that people tend to bring up as to why they think intermittent fasting is superior. However, there is a caveat to the data that intermittent fasting gurus like to ignore.
If you compared intermittent fasting to someone who was not fasting and both their diets had the same amount of protein and calories throughout the day, then there is virtually no difference in results. This is true for the effects on weight loss and the effects on LDL, HDL, etc.
What does this mean? This means that it was the restriction of calories that produced the results and not the fasting itself. You see, intermittent fasting is really just a way of restricting your overall calorie intake- specifically by restricting the time of day you are allowed to eat.
So, this means that for weight loss intermittent fasting is no better than if you had breakfast, assuming your daily calorie and protein intake are the same. This means if you want to have breakfast, you can absolutely do so and still lose fat.
Intermittent fasting and muscle growth?
This is something I see brought up less than fat loss by the intermittent fasters of the world. However, there are some who claim intermittent fasting to be good for building muscle, so it is worth bringing up here.
It is possible to build muscle when intermittent fasting, as there are studies that have shown people build muscle and strength when practicing this diet. However, it is definitely not optimal for building muscle.
The problem is that when you don’t eat for 16 hours straight, muscle protein synthesis (muscle growth) drops by a substantial amount. If your body is actively to build muscle and recover from a workout, then this is a problem.
Our muscles are constantly going through muscle protein synthesis (muscle growth) and muscle protein degradation (muscle loss). Whichever one of these processes happens at a higher rate will dictate whether we gain or lose muscle. If each day we have a 16-hour period where the process of muscle loss is greater than muscle growth, this can hold us back a good bit.
Is intermittent fasting right for you?
Let’s summarize what was just discussed about intermittent fasting. For fat loss or weight loss, intermittent fasting is equal to and no better than a normal calorie deficit. For overall health improvement endeavors, intermittent fasting is also equal to and no better than a normal calorie deficit. For muscle growth, intermittent fasting tends to be worse than a normal day of eating.
With all this mind, it is easy to dismiss intermittent fasting as pointless. However, I think there are some instances where it is really worth implementing. There’s a quote that Layne Norton says about these diets, that they are all just “tools in the tool box.”
For example, it was said previously that many people spontaneously lose weight when they start implementing intermittent fasting. This alone shows that for some people, intermittent fasting is optimal for some people. There are also some people who improve their weight and health just by eating less carbs. Even though carbs are perfectly fine to eat, it is their way of restricting calories that they can adhere to.
Also, I think for time management purposes, intermittent fasting is hard to beat. I personally don’t practice fasting, but I generally prefer to just wake up and get to work as opposed to make and eat breakfast.
Lastly, many people just do not get hungry in the morning. If this is you and you are trying to lose weight, then intermittent fasting might be the obvious answer.
It goes to show that good nutrition is different for everyone and needs to be individualized. One diet that works for one person is definitely the diet that will work for everyone.
References
Exercise Training and Fasting: Current Insights
PubMed ID: 32021500
Time-restricted feeding plus resistance training in active females: a randomized trial
PubMed ID: 31268131
Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial
PubMed ID: 29778565
