One of the fastest growing diet trends has nothing to do with what or how much you eat, however when You are Eating. Restricting meal times, a practice sometimes called intermittent fasting or time-restricted eating, comes in many forms, but generally involves limiting food intake to certain windows.
Interestingly, fasting is not just about losing weight. A great deal of research indicates that this behavior can induce a whole host of health benefits, from an improved mental state to restful sleep. Weight loss, of course, is the benefit that is often exaggerated. The Reddit forum for intermittent fasting, for example, has more than 860,000 members, many of whom share before and after photos of their massive weight loss.
Simply restricting food intake for 8 to 10 hours can change the way our genes express themselves, with broad implications for human health.
But while intermittent fasting has been linked to a myriad of health benefits, researchers still have many questions about it — like how it compares to calorie counting, how different populations respond, and even some basic questions about safety and side effects. One of the biggest questions is How do it’s working. On a molecular level, why does changing eating times seem to have such a dramatic effect on our bodies?
Dr. Satchidananda Panda, Professor of Biology at the Salk Institute for Biological Studies, has spent a great deal of time researching the underlying mechanisms of intermittent fasting. He says that simply restricting food intake for 8 to 10 hours can change the way our genes express themselves, with wide ramifications for human health.
In a recent study in the journal Cell Metabolism, Panda and colleagues gave two groups of young male mice the same diet that is obese, meaning that it is high in sugar and fat. 1 group allowed advertising reputation Breastfeeding who eats whenever she wants. The other group could only eat during specific hours, a form of intermittent fasting called time-restricted feeding.
The difference between time-restricted feeding and intermittent fasting is that people who fast intermittently also count calories. With limited feeding time, you can generally eat anything and as much as you want, you just need to stay between those eight to ten hours. In the experiment, mice on the Fame schedule gained weight and experienced metabolic dysfunction, while mice on the time schedule did not restrict their feeding. This is remarkable considering they were both on the same diet.
Next, Panda and his colleagues analyzed the organs of the mice, looking for genetic changes in 22 different regions of the organs and brain, and examined more than 21,000 genes from more than 1,000 samples. More importantly, they sampled at different times throughout the day and night. Gene expression can change throughout the day, depending on their function.
“Our genes are not fixed. So you can’t look once in a morning or evening and see what’s going on,” Panda told Salon. “And to our surprise, we found that almost every organ we looked at experienced a massive impact due to the temporal eating restriction.”
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More than 80 percent of the organs examined had some level of change in the genes that code for proteins, which means that time-restricted feeding can alter metabolic efficiency. In simpler terms, restricting the time you eat may make the entire way your body processes energy more fluid, which translates to other health benefits.
On the surface, this is not an entirely surprising result. Intermittent fasting has previously been linked to improved liver function, insulin sensitivity, and even hormone regulation. It seems to have a broad effect across many different systems in the body, but some of these organs, especially the brain, have been looked at much less often than others.
“We are seeing imprinting of gene expression changes that suggest people with chronic kidney disease may benefit.”
Of course, this research was done on rats, and only male rats that boot. This may not translate directly to humans. But the research provides a “transcriptome map” that gives researchers a good idea of where to start looking next when researching intermittent fasting. Potential targets include metabolic disorders, neurodegenerative diseases, and cancer.
“I think this is a good blueprint for treatable diseases,” Panda said. “This study gives us clues, for example, in the kidneys. We are seeing imprinting of gene expression changes that suggest that people with chronic kidney disease may benefit from this.”
Panda has studied the effects of intermittent fasting in humans as well, such as in an experiment with 15 obese Australian men who were maintained on a restricted diet for eight weeks.
“We biopsied them. They removed a little bit of belly fat, like mini-liposuction,” Panda explained. “What we found were good changes in gene expression in these individuals, which now gives us an idea of what to expect when people with obesity restrict food intake.”
“Our adipose tissue, or fat, is very much like a hormone-producing organ. It produces a lot of different hormones, good and bad,” Panda added. Time restriction actually improves the production of feel-good hormones.
Studying intermittent fasting could also open the door to new therapies, such as drugs designed to target these gene expressions, perhaps without the need for time restriction. Already, drugs that target specific metabolic pathways and can reduce weight in some individuals are becoming all the rage on social media. Semaglutide, also known by the brand names Wegovy or Ozempic, is a diabetes medication sometimes used for weight loss. It has become so popular that it has caused shortages in some areas, which has encouraged some patients to seek risky alternatives or try brewing it at home using raw chemicals. It should go without saying that you should not attempt to make your own weight loss drug.
However, the long-term effects of semaglutide for weight loss are not well known. Many people seem to regain the lost weight once they stop taking the medication, which can be accompanied by a host of side effects such as indigestion and nausea.
Newer drugs that are more effective to meet the demand for obesity and diabetes treatment are essential and a study of intermittent fasting could help produce them. This is to some extent how metformin, a commonly prescribed drug for diabetes, was discovered. Although initially synthesized in the 1920s, it wasn’t until 1957 that metformin was first used to treat diabetes. The reason for this multi-decade gap is because scientists don’t fully understand the mechanisms it uses to lower blood sugar levels. Unfortunately, despite the widespread use of metformin today, it still comes with some side effects that can be serious, even life-threatening. Certainly, alternative medicines will be beneficial for some people.
But there will be no silver bullet to any of this. Panda said that medications or intermittent fasting alone cannot form the basis for a healthy lifestyle.
“We have to keep in mind that the drugs will not give us long-term benefits. They will help us reverse the course of our disease,” Panda said. “But to stay healthy in the long run, we have to embrace at least two of the three foundations of health: sleep, exercise, and nutrition.”
The full extent to which intermittent fasting can help people, or even backfire, is not fully known. Few things are as complex as how human bodies convert food into energy. More detailed research on how time-restricted eating works will help us better understand the ways in which it is beneficial for promoting good health.
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