Sky Radoci spent years trying to find something that could cure his eczema, which developed during a bout of stress he went through when attending music school in Los Angeles. Steroid creams helped temporarily, but his condition stubbornly came back as soon as he ran out. Looking for a longer-term solution, he was eventually able to wane off the creams altogether after changing one part of his routine: his diet.
Radoci, a musician based in Costa Rica, now fasts for the majority of the day, eating a large portion of meat, plantains and some fruit in about a six-hour period starting around 5 p.m. In the five months since he has been fasting with this keto diet, his eczema symptoms have disappeared, and Radoci says he feels better than he ever has.
“This might not be for everybody and this might not be for a whole lifetime,” Radoci told Salon in a phone interview. “But for right now, it feels like it reset my body. I just feel better.”
Eating one meal a day (also known as OMAD) is the latest weight loss trend to storm the internet, endorsed by celebrities like Bruce Springsteen and even former British Prime Minister Rishi Sunak. This and other forms of intermittent fasting like the “warrior diet” have been touted as ways to lose weight by triggering your body’s “survival mode.” The essential idea behind many of these techniques is that restricting meals to a smaller time frame in the day will make you consume fewer calories, said Dr. McKale Montgomery, a nutritionist at Oklahoma State University.
“For most of these intermittent fasting diets, people don’t have as much time to eat as they normally would, so the weight loss ultimately comes from just consuming less calories,” Montgomery told Salon in a phone interview.
Doctors in Ancient Greece prescribed fasting to cure certain illnesses, and it has been and still is used in various religious or spiritual practices.
Although intermittent fasting may be no more beneficial for weight loss than calorie-restriction and extreme trends like OMAD might not be sustainable for the majority of the population, fasting in general has played an important role in human history, and many of the modern-day trends stem from ancient practices.
Our ancestors would naturally fast after a failed hunt until they were able to recuperate the calories they needed to sustain themselves. Doctors in Ancient Greece prescribed fasting to cure certain illnesses, and it has been and still is used in various religious or spiritual practices. In one Japanese tradition, tracing back to the 10th century, monks fast for nine days after walking a marathon distance for 1,000 days around Mount Hiei to bring themselves closer to enlightenment. Today, about 2 billion people fast during Ramadan each year.
Some argue that the proliferation of available food through refrigeration and other technological advancements has shifted our eating patterns in modern times, such that we eat more often than our bodies are evolutionarily accustomed to. Animals in the wild, including our hunter-gatherer human ancestors, live or lived in environments where food was relatively scarce and had to expend much more effort to acquire it, said Dr. Mark Mattson, a neuroscience professor at Johns Hopkins University School of Medicine who studies fasting.
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“There was competition for limited food sources,” Mattson told Salon in a phone interview. “So individuals whose brains and bodies functioned very well in a food-deprived state had a survival advantage because your brain and body had to be working well to get food.”
Mattson said fasting in part works by activating the body’s stress response, which can have physiological effects — similar to intermittent exercise, where the body is put under a state of stress to get stronger.
“It’s a stress on your muscles, your heart cells, even the neurons in your brain become more active during physical exercise,” Mattson said. “They respond to that energetic challenge by enhancing their ability to resist stress and function better, and these cycles of challenge and recovery through fasting and eating over the period of weeks and months can optimize health.”
In the metabolic process, the body converts food into glucose that it burns for energy. When fasting, these glucose stores run dry, and the body begins using fats as energy sources instead. However, the body cannot run on just fat for energy, and it also begins to convert its own proteins into glucose — essentially eating itself. In this process, the body also begins to produce molecules called ketones, which substitute glucose when it is not available.
“There’s a lot of emerging evidence that [ketones] actually act as a hormone and are not only an energy source for cells when glucose isn’t available,” Mattson said. “[They] also activate genes and have other effects on cells that stimulate them in ways that make them more resilient and also better able to conserve resources and recycle things.”
Some limited research has shown that time-restricted eating might help people lose weight, though most of these studies in humans have been performed in people who are overweight or have obesity. Other studies have shown that fasting could help longevity, memory, and cardiovascular function, but the majority of this research testing the effects of intermittent fasting on the body have been done in animals.
For the OMAD diet, one 2022 study published in Frontiers in Physiology found people did lose more weight and burn more fat when they ate one meal per day compared to eating the same amount of calories across three meals — though the study was small and short, measuring these factors in 11 young people for just 11 days.
Dr. Nick Fuller, an obesity expert at The University of Sydney and founder of the Interval Weight Loss program, said our body’s system is designed to protect against weight loss to survive, so many people might still not lose weight when following these programs.
“When we change our diet to lose weight, we take our body out of its comfort zone and trigger its survival response,” Fuller told Salon in an email. “It then counteracts weight loss, triggering several physiological responses to defend our body weight and ‘survive’ starvation.”
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Plus, extreme diets like OMAD might not be sustainable for many, Fuller said. These regimens could also lead some people to develop an unhealthy relationship to food, as some might feel deprived or socially isolated at meal times, he added. Restricted eating could also lead to nutritional deficiencies, depending on what the diet consists of.
For certain groups, like those who have a history of eating disorders or pregnant people, fasting could also introduce health concerns. Ultimately, like any dietary change, whether fasting works for the individual depends largely on their body and schedule and should be discussed with their doctor if there are any doubts.
Aryan Zainaleain, an entrepreneur who runs a yerba mate company, has been intermittent fasting for two and a half years. For him, breakfast always felt forced, and it was more natural for him to reserve his meals for the time before bed.
“I don't know my method of intermittent fasting would be advised for everybody,” Zainaleain told Salon in a phone interview. “But this regimen resonates with my body.”
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