Almost everyone, it seems, is intermittently fasting. Celebrities, my boss, my friend's boyfriend, my mother.
Twitter's CEO, Jack Dorsey, only eats once a day. He doesn't have breakfast or lunch, but consumes his sole meal between 6:30 p.m. and 8:30 p.m.
While Dorsey's approach is extreme (and not recommended), intermittent fasting is widely promoted, with a plethora of book titles that promiseit'll "supercharge energy," "optimize weight," "activate stem cells" and "slow aging." There's also intermittent fasting apps that track the fasting window and weight loss.It is, after all, part of a booming global diet industryworth$189 billion (175,45 billion).
While fasting has long been a cleansing ritual for many cultures and religions(albeit more so in a spiritual sense),its arrival on the modern wellness scene raises some serious health questions, not least about why we should follow a diet many proponents say is good for us because it's based on what our primitive ancestors did. Foremostly, what exactly is intermittent fasting, and why do it?
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What's intermittent fasting?
An eating pattern that restricts calorie intake to certain hours of the day or days of the week, intermittent fasting has several different iterations.
One of the most common examples, popularized by science journalist Michael Mosley, is the 5:2 diet. You eat unrestricted for five days of the week and limit calorie intake on the other two days of the week, usually to around 500 kcal.Mosley says it reversed his type 2 diabetes.
Time restricted eating, on the other hand, limits intake to a block of time in the day (usually between eight and 10 hours), and alternate day fasting, as the name suggests, limits calorie intake every other day.There are alsomore extreme versions, including the so-called "warrior diet," which alternates between 20 hours of undereating and four hours of unlimited eating. But because no health professional would recommend doing that, it hasn't been studied.
The main idea behind intermittent fasting is to give the body's insulin levels enough time to go down between meals so our fat cells can then release their stored sugar to be used as energy.Positive buzz about the diet spiked after a series of successful studies on rats, which lost weight, improved their blood pressure, cholesterol and blood sugars, and even reduced their risk of type 2 diabetes and cancer.
But unlike lab-bound rats, it's much more difficult for humans to follow rigid dietary rules and, in part, that's made it difficult to carry out long term studies on humans.
What's the latest?
One of the newest studies on the topic, published in Cell Metabolism, found restricting eating to a 10-hour window during the day had positive health benefits for overweight people with high cholesterol levels, elevated blood sugar and high blood pressure. After three months, the participants who were not asked to change what they ate lost around 3% of body fat and 4% of abdominal visceral fat.
This could suggest a 10:14 circadian rhythm-fasting approach (eating between 8 a.m. to 6 p.m.) is effective for people with metabolic syndrome, except that the study was only carried out with 19 participants over three months.
That's simply "too small and too short," according to Tilman Khn, a nutritional epidemiologist from the German Cancer Research Center. The study was also crucially missing a comparison to a conventional calorie reduction diet, Khn said.
"My interpretation is that people just benefitted from professional dietary support," Khn told DW.
Satchidananda Panda, a professor at the Salk Institute andco-author of the study, said while "more research is needed" to establish whether time restricted eating or intermittent fasting can really help reverse the issues created by an unhealthy diet, he added they have found that "people sleep well and feel more rested in the morning" while on a 10:14 diet.Panda is also an author of one of those book titles, the subheading of which reads: "lose weight, supercharge your energy and transform your health from morning to midnight."
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No better than conventional dieting
Previous research has found intermittent fasting to be no more effective than conventional calorie reduction diets for weight loss or improved insulin levels.
A recent study co-authored by Khn, carried out over a 50-week period, compared a 5:2 intermittent fasting diet with a continuous calorie reduction diet, whereby participants reduced their daily calorie intake by 20%. A third control group didn't change their diet.
Researchers found that both intermittent fasting and calorie reduction led to weight and fat loss in comparison to the control group. Some health markers, like insulin levels and lipids, also improved. But these results were almost identical for both diets.
"We found no evidence at all for a stronger effect or greater benefit of intermittent fasting," Khn told DW. "It was equally as effective compared to a traditional moderate daily calorie reduction diet."
While Khn says he "would never trust just one study," two other comparative, year-long studies from Norway and Australiaconducted around the same time found exactly the same result 5:2 intermittent fasting is no more effective than calorie reduction.
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Tough to follow
Panda, though, says this is one of the main appeals of the 10:14 fast, as he thinks it is much easier to follow than other forms of intermittent fasting or conventional dieting.
"Even if two methods lead to similar outcomes, why would you prefer something that is difficult to follow?" Panda said.
The issue with the claims made by small-scale studies and the intermittent fasting book titles, though, is that, like many fad diets, it's presented as a miracle solution. When in actual fact, the science is not so clear.
"If someone finds that intermittent fasting is working, then I would say it's a good method for them. But it's not a universal solution to any health problem for everyone," Khn said.
In light of the evidence we have so far, he said the scientific community may be better off looking to policy measures (like the sugar tax in the UK) as a way of preventing obesity and unhealthy eating habits, as opposed to appealing to individuals to change their eating behavior.
Our skin is often the starting point for how we perceive situations and interact with one another. Researchers have found that people can detect certain emotions, like love, anger, gratitude and disgust, from touch. Regular positive touch has been shown to reduce aggression and increase pro-social behavior. It also helps us form and maintain emotional bonds in relationships.
Touch, or tactile communication, can help us build trust and cooperation. One study even found that professional basketball players and teams who had more physical interaction early in the season, like high fives and team huddles, performed better in later games.
Hugging is a sign of support that can reduce stress. They can also help deter inner turmoil after conflict. One study showed that people who received a hug on a day when a conflict had taken place were found to be in better moods afterwards. Hugs have also been shown to reduce the likelihood of catching a common cold, due to their stress-buffering properties.
Warm contact between partners, like holding hands or cuddling, can contribute to better cardiovascular health and can lower one's reactivity to stress. This is because that positive physical sign of support slows your heart rate, decreases the stress hormone cortisol and lowers your blood pressure. Couples can even sync their heart rates and brain waves just by touching.
Researchers at Duke University Medical Center found that full-body massage relieved pain and increased mobility in patients with arthritis in their knees. Therapeutic touch has also been shown to decrease pain and increase the quality of life for fibromyalgia patients. Not just those getting a massage see benefits, either: Giving a massage also offers positive improvements to personal well-being.
Massage has also led to weight gain in preterm babies by engaging part of their nervous system. This improves digestion and releases hormones required for absorbing food. Skin-to-skin touch helps release oxytocin, the hormone related to mother-infant attachment, and decreases cortisol, the stress hormone. It may also have a pain-relieving effect for babies undergoing minor medical procedures.
You don't need another person to receive the benefits of touch, though. Self-massage can have some of the same effects of regular massage. The health benefits are stronger when more pressure is applied, as opposed to a lighter touch. Yoga and other forms of exercise, with physical contact between your body and the ground (or weights), can produce similar stress-relieving effects, too.
Support in the form of holding a partner's hand when they're experiencing physical pain may be beneficial for both the recipient and the giver. Pain is actually diminished for the affected partner when touched. This contact can also help people with low self-esteem to eliminate self doubt.
Today, work is being done to create sensory-enabled prosthetics so that amputees can get the same health benefits from touch. Psychological well-being has been shown to increase for those who used such prosthetics. Other researchers are also working on developing electronic skin technology that can feel hard surfaces, soft fabrics or sensations like heat.
Author: Sam Baker
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Intermittent fasting: Is it worth the hype? | DW | 10.12.2019 - DW (English)
