Experts indicate that the rapid dissemination of supposed benefits of food abstinence is due in large part to social networks. They point out, for example, that many food myths go viral on the internet and people echo this and immediately begin to implement it to see if it works. However, not everything is “pink”, as the research raises doubts about whether the advantages of fasting really serve the entire population or at least a large part of it.
Intermittent fasting proposes going long periods without eating a day
“Lying in my bed one sunny morning, the wind was coming through the open window and I caught a nauseating smell. I thought it would be leftover food in the garbage cans, since there was no explanation for such a smell. It smelled like rotten meat. It was after closing the bedroom window that I realized with horror that the smell was not leaving the room, but intensifying. That is when I realized that the stench was mine”, a 27-year-old reader told La Nación, who prefers to remain anonymous and who did intermittent fasting for 16 hours for 15 days.
This story is closely related to one of the unwanted side effects of intermittent fasting. It is a practice that has become fashionable in recent years and has as its main followers renowned celebrities such as Jennifer Lopez, Reese Witherspoon, Jennifer Aniston, Heidi Klum, Hugh Jackman and Chris Hemsworth.
The latter incorporated the habit when he was preparing for her role in the movie ‘In the Heart of the Sea’, for which he was required to lose more than 10 kilos. To achieve this, Hemsworth ate only 500 to 600 calories a day and practiced intermittent fasting. “I was doing a 15-hour fasting period. Sort of like stopping eating completely and then eating small meals throughout the day”, the actor said on Jimmy Kimmel Live.
Among its benefits, its faithful practitioners and recognized institutions such as the Mayo Clinic highlight that adopting this habit helps reduce inflammation, lose weight quickly, improve heart and brain health, among others. However, it also has disadvantages such as hunger, fatigue, insomnia, nausea, halitosis, headache, and body odor.
What is intermittent fasting?
Intermittent fasting is not a diet; it is a practice that involves abstaining from eating food for a certain time in which long periods of fasting are combined with others in which you can eat freely. It is considered as the voluntary interruption of food for hours and even days for the most extremists.
Nutrition graduate Juliana Giménez explains about the duration of fasting: “There are people who do it for many hours, while others for less”. She indicates that usually the most normal ranges that are implemented are to eat food only for 8 hours of the day and the other 16 to drink water and sleep.
There are also more demanding patterns where the eating window is 4 hours and 20 hours of fasting, and more extreme instances in which 4 meals a day are consumed and the next day no food is eaten for 24 hours. So successively, the days in which the person fasts completely alternate with others in which the person eats “normally”.
In recent years, fasting has become increasingly popular, whether to improve health or drop extra pounds. For Ms. Giménez, her rapid popularity is largely due to social media. “Many food myths go viral on the Internet and people echo this and immediately start implementing it to see if it works”, she highlights.
However, not everything is “rose color”. Although several of the benefits mentioned above have been verified by professionals, the variation in research methods raises questions about whether these advantages of fasting really serve the entire population or at least a large part of it.
Body odor: A common currency for those who practice intermittent fasting
Intermittent fasting can also cause headaches and migraines. Some of the people who fast for years are familiar with the “typical smell of fasting”. For those who have detected it, it is similar to rotting food and can be very unpleasant, especially for those who are related to those who follow this practice. Now, why is this happening? According to Ms. Giménez, the stench is due to the fact that the body enters ketosis -a metabolic state that occurs when there is not enough glucose. Then the body uses fats and ketones in order to produce energy.
During this period, stored fats in the body begin to be burned for energy, instead of using glucose from food, which is needed because it is not being consumed. For this not to happen, the body needs the person to eat at least 50 grams of carbohydrates a day to be able to convert fat into glucose.
Added to that, Giménez points out that certain people may notice an unusual odor in their own body during fasting. While others are not aware or cannot perceive it. “In general, the person who produces the characteristic body odor of fasting usually does not notice it, but they can detect it in others”, she explains.
Another unwanted addition: Halitosis
According to that Dental Clinic, fasting causes bad breath because it creates a state of hypoglycemia that causes the body to use alternative metabolic pathways. This means that sugar levels must be kept balanced and by not eating food, bad-smelling compounds are often generated with some fatty acids that are released.
Along the same lines, Ms. Giménez adds that another reason for halitosis is a reduction in saliva production. This can cause the mouth to dry out and lead to bad breath. To avoid this, she recommends hydrating and consuming enough fluids to maintain saliva production and prevent dry mouth.
Other unwanted side effects
Both halitosis and body odor stand out as unexpected and uncommon side effects in eating plans or habits. However, there are other symptoms of discomfort that appear when intermittent fasting is performed.
Intermittent fasting side effects are very normal
One of the most frequent adverse effects of fasting is headaches or migraines. Interestingly, in a study titled “Fasting Headache” researchers discovered that the aforementioned headaches occur in the frontal region of the brain and that those who suffer from it the pain is usually of moderate or high intensity. Added to this, for scholars, having low blood sugar levels -due to the absence of food in the body- and withdrawal from caffeine or infusions could be the cause, to a large extent, of the famous headaches during intermittent fasting.
Digestive problems are also frequent in those who acquire this “detox” habit. Some of the most common complaints are constipation, diarrhea, nausea, and bloating. In the article “Health Effects of Alternate Day Fasting in Adults”, published in the scientific journal Frontiers, it is detailed that the participants observed in the study reported suffering from constipation during the first two weeks of the trial and that in part this could be related to dehydration. Another side effect related to fasting that can make constipation worse.
Added to that, changes in mood also appear as a characteristic factor of implementing intermittent fasting. Some people who do this practice may experience irritability and other mood disorders when they restrict their eating. According to the professionals of the American Journal of Clinical Nutrition, this is because when the blood sugar level is low, the brain becomes unbalanced and this generates irritability, anxiety, and lack of concentration.
Another research also suggests that intermittent fasting is directly related to sleep disturbances. Problems such as not being able to fall asleep, having insomnia or staying asleep during the day, are among the most frequent side effects in people who carry out the voluntary interruption of food.
Finally, for Ms. Giménez, the appearance of these adverse effects or the effectiveness of doing intermittent fasting depends largely on whether it is a practice supervised by nutritionists or health professionals who take into account the patient’s clinical history and warn if is the indicated feeding method.