Intermittent fasting and sports - benefits and negatives

What is intermittent fasting?

Intermittent fasting is a way of eating in which we do not eat for several hours during the day. Usually it is a 12-18 hour fasting interval. All daily intake is therefore consumed within 6-12 hours. We can achieve this by, for example, skipping one meal and increasing the portion of the remaining meals, or by spacing out multiple portions closer together and then the fasting interval comes.

So what does it look like in practice?

If you're unsure how to schedule your diet, you can be inspired by the examples of daily fasting windows below.

There are of course many more options for time windows for fasting and it depends on individual preferences, the table serves to give you an idea of what intermittent fasting can look like. Some people may find it convenient to have their last meal at 5:00 PM, while others may prefer to skip breakfast and have lunch as the first meal of the day. Both options fall under intermittent fasting .

What are the benefits of intermittent fasting?

Should you eat within 30 minutes of waking up and then every 2-3 hours, or should you try intermittent fasting? The vast amount of information and recommendations is often confusing. So is intermittent fasting right for you? It can be very individual.

Intermittent fasting has been shown to have many positive health effects beyond just weight loss . ¹ These include reducing cellular inflammation in the body, reducing the risk of metabolic syndrome , and reducing fat accumulation in the liver by timing meals more optimally in accordance with the circadian rhythm . Our bodies naturally have their own “internal clocks” that are in line with the 24-hour daily cycle. Physiological processes such as digestion change in our bodies in accordance with this rhythm and reach their optimum at certain times. However, in our day and age, we generally do not respect circadian rhythms very much, which may not be beneficial for our bodies. This does not mean that our bodies are unable to digest properly during certain parts of the day, but that they are more prepared for the digestive process at certain times of the day, and this can also vary from person to person. ²

Intermittent fasting has also been shown to be more beneficial and healthier than eating patterns that involve frequent meals throughout the day. ³

What could be the negatives?

Although intermittent fasting is not dangerous for a healthy person, some people may experience side effects such as headaches, fatigue, nausea, or mood swings. This is very individual, so if you find that intermittent fasting does not suit you, it is better to find an eating regimen that you will not have difficulty maintaining . ⁴

What is the effect of intermittent fasting on athletic performance?

Intermittent fasting has not been shown to have a positive effect on athletic performance. ⁵ A short-term study found that intermittent fasting had no negative effect on medium-term athletic performance, such as a soccer match. ³

No significant changes in performance were observed in endurance athletes. It is important for athletes to plan their meals during intermittent fasting to ensure they have enough energy for athletic performance and recovery, and it is generally advisable to provide the body with at least some energy both before and after exercise.

Does intermittent fasting affect muscle mass?

If you are wondering whether it is possible to maintain or gain muscle mass during intermittent fasting, the answer will be found in the composition of the diet . Studies have shown that in the case of weight loss, muscle loss during intermittent fasting was not higher than with other methods of reduction. On the contrary, in a group of athletes trying to gain muscle mass, the increase was lower with intermittent fasting than with a normal diet. But is this due to the timing of meals? No. This result was due to the fact that in a shorter time window, athletes were not able to consume a sufficient amount of nutrients , especially protein, which is necessary for muscle growth. If you play sports or are involved in bodybuilding or some form of fitness and you start intermittent fasting, you should make sure that you manage to eat all the necessary nutrients for your body in the time window. ⁶

Conclusion

Intermittent fasting does not endanger our health and does not demonstrably slow down our metabolism. ¹ It is possible that some of us observe intermittent fasting unconsciously by, for example, having dinner around seven o'clock and breakfast again around seven - thus creating a twelve-hour fast. Intermittent fasting is therefore not a recent discovery. It brings many benefits, for some it may be the ideal way, for others it may not suit them, it is certainly not the only right option. However, if your eating regimen does not suit you and you want to try a change, you do not need to worry about intermittent fasting, you will see for yourself whether it suits you.

Resources:

1. https://pubmed.ncbi.nlm.nih.gov/34633860/
2. https://pubmed.ncbi.nlm.nih.gov/35070352/
3. https://bmjopensem.bmj.com/content/8/1/e001206
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9998115/
5. https://pubmed.ncbi.nlm.nih.gov/31283627/
6. https://www.healthline.com/nutrition/11-myths-fasting-and-meal-frequency?fbclid=IwAR0xYaTHgU-_848fzt6eVOpo8QYjknBqhvnMtVRkL-A2OoRsdLwEUIxsxcw#TOC_TITLE_HDR_13