What’s the real deal about intermittent fasting?
Hugh Jackman does it. Queen Bey does it. And it’s all what YouTube fitness vloggers are talking about. Intermittent fasting has become a way of eating.
And why not? It’s easy, simple, and experts recommend it for a bunch of benefits.
Unlike a constant low-calorie diet or an extreme diet that requires you to cut out certain food groups like carbohydrates altogether, intermittent fasting intersperses normal eating with a meal skipped every now and again. It could also mean a day or two of fasting in between regular days.
Fasting does not have to be an uphill task. In fact, when you go to sleep every night, you are in effect allowing your body to fast for the 8 hours that you sleep and until you have breakfast. Recent research has found that intermittent fasting offers a range of health benefits. So what are these benefits?
Fat burning and weight loss
Increased fat burning is the most obvious benefit of intermittent fasting. When you go on a fast, your body’s glucose and insulin levels drop significantly. In the absence of glucose, the body turns to fat burning. One small study of non-obese men and women found that fat oxidation rates increased after alternate-day fasting.
Human growth hormone levels also rise significantly after fasting. This hormone is said to help with fat burning as well as muscle gain. Research has shown that it can increase lean body mass and bring down fat mass in healthy seniors of both genders.
Intermittent fasting can boost: basal metabolic rate by 3.6%, resting energy expenditure by 14%, fat loss by 4%–7%, and weight loss by 3%–8%.
Inevitably, this leads to weight loss. First, since you’re eating fewer meals, it reduces your daily calorie consumption. Second, it increases your basal metabolism — the rate at which you burn calories when at rest. In one small study, researchers found that fasting completely (starvation) for 48 hours caused basal metabolism of the subjects to rise by about 3.6% on an average.
In another piece of research, the metabolic rate, as measured by resting energy expenditure, rose by around 14% on the first day of a multi-day (84-hour) fast. This change in metabolic rate could be because, as mentioned earlier, fasting enhances the functioning of growth hormones. It also increases the amount of the hormone norepinephrine, which encourages fat burning, and all of these factors play a role in the breakdown of body fat.
Hence, intermittent fasting may allow you to benefit from this raised metabolic rate to burn off calories — without having to fast for long periods of time. In fact, one study conducted on type 2 diabetics found that intermittent fasting can help people lose up to 3–8% of body weight and 4–7% of fat from their waist over the course of 3–24 weeks!
Improves diabetes symptoms
Diabetics could benefit from intermittent fasting, provided they do it under medical supervision. Intermittent fasting has been found to:
- Hike insulin sensitivity: Diabetics typically suffer from low insulin sensitivity, which leads to high insulin as well as glucose levels in the blood. Excess insulin is also harmful in the long run. In a study, male participants who fasted intermittently noted a reduction in their blood sugar levels by 3–6% and in their fasting insulin levels by 20–31%.
- Regenerate beta cells in the pancreas: Type 1 diabetics have very few insulin-producing beta cells in their pancreas, which is what causes the diabetes. Mice study has shown that fasting intermittently can even help regenerate the insulin-producing beta cells in the pancreas.
- Prevent diabetes complications: Yet another study found that this form of fasting prevented kidney damage, a common diabetes complication.
Remember, the key is to fast “intermittently.” If you constantly go on a fast, you may actually end up with more abdominal fat as a result of impaired morning glucose tolerance and delayed insulin response.
Reduces inflammation
Inflammation is the body’s natural (immune) response to an injury and foreign invaders (such as viruses and bacteria). However, chronic inflammation has been connected to a number of illnesses that plague people today — such as arthritis, diabetes, heart disease, Alzheimer’s, and cancer.
Besides lowering inflammation, by maintaining brain structure and function, intermittent fasting is believed to ease chronic pain.
Research indicates that when you fast, your body releases ghrelin, the hunger hormone, which is known to lower inflammation and aid in the treatment of any diseases associated with it. In addition to this, intermittent fasting reduces the number of inflammatory proteins called cytokines.
And considering how fasting for just one meal can make a difference, intermittent fasting is often recommended for people with inflammatory disorders.
Prevents heart diseases
Alternate-day fasting has been found to help reduce levels of triglycerides while improving levels of good high-density lipoprotein (HDL) cholesterol. Both these factors are essential in protecting the heart. In addition to this, intermittent fasting lowers blood pressure and resting heart rate in the same way as intensive exercise does. While a stable blood pressure promotes cardiovascular health, a lower heart rate at rest indicates better heart function and cardiovascular fitness.
Lowers risk of metabolic diseases
Research on animal test subjects shows that time-restricted feeding can help prevent metabolic diseases like liver disease and obesity even on a high-fat diet. This could be because fasting improves cell signaling (communication between cells) and increases metabolism.
It comes as no surprise then that experts have been recommending intermittent fasting to individuals with metabolic diseases.
Improves digestion
Fasting boosts the production of hormone ghrelin, the hunger hormone. This hormone plays an important role in digestion and gut health. It prepares the body for nutrient absorption by secreting gastric acid and stimulating the movements of fluids in the gastrointestinal system.
This could be why fasting has been shown to improve symptoms like abdominal pain, diarrhea, and nausea caused by colitis, ischemia, and irritable bowel syndrome.
May improve sleep
If you tend to toss and turn at night and wake up every morning extremely groggy and sleep deprived, you might benefit from intermittent fasting. One study states that it improves the quality of sleep and reduces the number of times one wakes up in the middle of the night. Some experts claim not eating anything for 16 hours before waking up could improve sleep quality.
However, other studies note that people who practice intermittent fasting may experience sleeplessness and daytime sleepiness as a side effect.
Since there are mixed results on the effects of intermittent fasting on sleep, it’s best to consult a doctor first, especially if you are under treatment for insomnia.
Promotes skin health
There is some evidence that links intermittent fasting to faster wound healing. However, this isn’t the only benefit that this form of fasting brings with it.
Studies state that it can aid in alleviating contact dermatitis and chronic urticaria — allergic reactions on the skin.
It is believed that fasting intermittently can also reduce acne breakouts, but there isn’t enough research to back this up.
Boosts mood and motivation
If you’ve been feeling low of late, you could try intermittent fasting. Since it improves sleep, this form of fasting is also linked to an increase in motivation and better daytime performance in general tasks. Consuming fewer calories and fasting intermittently has also shown to lower depression and improve mood in aging men. This could be due to the fact that intermittent fasting boosts ghrelin, which is linked to the hippocampus, the part of the brain that is responsible for emotion.
Promotes brain health
Studies have found that intermittent fasting can also promote brain health. For instance, this form of fasting could help protect you against the effects of genetic and environmental factors that play a role in the aging of the brain and any associated frailty such as muscle loss. This form of fasting is also associated with the growth of the hippocampus, the part of the brain that is responsible for emotion and memory.
Studies have noted that learning might be the best when one fasts during the day because this is when ghrelin levels are high. Ghrelin helps regenerate brain cells.
Besides this, a study conducted on mice noted that regular intermittent fasting improved their memory and learning.
May prevent Alzheimer’s, Parkinson’s, and Huntington’s disease
Neurodegenerative diseases don’t have a cure, which is why preventing them is critical. Scientists link the overactivity of nerves to degenerating diseases like Parkinson’s, Alzheimer’s, and Huntington’s disease.
Fasting has been seen to boost the production of a protein called BDNF, which in turn promotes the production of neurons. This may counter nerve-degenerating diseases like Alzheimer’s.
Preliminary studies state that intermittent fasting may:
- Slow down the onset of Parkinson’s disease by increasing the production of ghrelin, the hunger hormone. This hormone increases the concentration of dopamine in a part of the brain where the decline of dopamine cells causes Parkinson’s disease.
- Delay the onset of Alzheimer’s disease or reduce its severity. Daily short-term fasts improved the symptoms of Alzheimer’s in 9 out of 10 patients.
- Delay the onset of Huntington’s disease and increase the life span of patients
Alleviates asthma symptoms
As stated earlier, intermittent fasting reduces inflammation and oxidative stress in the body. And this, in turn, can improve the symptoms of asthma, especially in people who are overweight. This applies to those with milder forms of asthma.
Researchers have found that skipping just one meal of about 400–500 calories every other day could reduce difficulties in breathing.
Fights infections
Fasting boosts the production of neutrophils, a type of white blood cells, and immunoglobulin A, an antibody that plays a critical role in immune function. This helps your body fight off infections by bacteria like Salmonella. Intermittent fasting has also shown promise in preventing damage to the brain during the course of an infection.
May improve symptoms of autoimmune diseases
Fasting intermittently is believed to lower the autoimmune response and promote the regeneration of immune cells. A study has shown that this form of fasting may reverse the symptoms of multiple sclerosis, lupus, and vasculitis. Further studies are required to establish intermittent fasting as a mode of managing autoimmune diseases.
Prevents cancer
We already know that intermittent fasting lowers blood glucose levels. Recent studies have shown that it also lowers levels of the hormone IGF-1 (insulin-like growth factor) in the body. These together contribute to a lower risk of cancer.
Studies conducted on animals have also noted a lower incidence of cancer after fasting every alternate day.
To add to this, reducing one’s caloric intake and fasting for longer intervals during the night has been found to reduce the risk of breast cancer.
Extends lifespan
Considering the range of health benefits that have already been listed, it’s no surprise that intermittent fasting is known to increase one’s lifespan. For one, it delays aging by protecting the body from disease. It also works on the biological pathways that prolong the health span of the nervous system.
Intermittent fasting may extend your lifespan by up to 30%.
Besides this, intermittent fasting boosts the body’s stress resistance, which increases longevity. Studies conducted on rats found that those that fasted regularly lived 83% longer than rats who didn’t. Other studies conclude that intermittent fasting can increase a person’s lifespan by up to 30%.
Choose among the 5 types of intermittent fasting
- 16:8 — Fast for 16 hours, eat all you can in 8 hours.
- 5:2 — Fast for 2 days a week, eat for 5 days.
- Alternate-day — Fast every alternate day.
- Warrior diet — Fast during the day, eat at night.
- Eat stop eat — Fast for 24 hours once or twice a week.
But take caution! Intermittent fasting is NOT for everyone
Fasting of any kind is best undertaken under the guidance of a qualified dietician or nutritionist who can help you with your meal planning. Even something as seemingly harmless as intermittent fasting that involves skipping just one meal now and again could be dangerous for some people. Here are some instances where fasting without supervision is not a good idea:
- If you are pregnant
- If you are diabetic or have insulin resistance or other blood sugar regulation problems
- If you have any kind of eating disorder
- If you don’t sleep well
- If you have any other health problem that could endanger your life or worsen your condition if you skipped meals or didn’t eat at regular intervals
- If you are not an adult — children with growing bodies have different nutritional needs and more active lifestyles than most adults. If it is required for religious reasons, it is best done with utmost care and with careful planning and under the guidance and with the consent of their parents.
If you fall under any of the above categories, it might be best to avoid intermittent fasting or consult a professional before taking it up.