Image: Empty Plate
In the past couple of days, I’ve been reading up on fasting with much interest. Being a girl in her 20s, I’m all about the latest diet trends. Ever since high school, I’ve had a poor body image and one of the few diets I tried at the time was intermittent fasting. Obviously, back then I took it to the extreme and would go days without eating. Now, living a healthier lifestyle, I was surprised to learn about the health benefits of fasting, when you don’t take it to the extreme.
Fasting may be the latest diet trend, but it has been a practice within various religions for a long time. It goes back as far as ancient Greeks, who were amazed by the impact it had on the body and mind.
The first experiments on feeding lab animals on alternate days began in the 1940s, says Michelle Harvie, a research dietitian in Manchester, England. Finally, in 1946, the first study on fasting was posted by The Journal of Nutrition. The study demonstrated an increase in life-span and a decreased likelihood of tumour development in rats deprived of food every third day compared to other control animals.
By the 2000s, the idea of fasting was growing in popularity, including a documentary airing on BBC in 2012 and a book followed the next year. In 2003, another study by Mark Mattson found that putting mice on alternate feeding days were healthier than putting mice on a calorie-restricted diet.
There are different methods of practice. On my healthier days, I practiced time-restricted feeding, such as eating for only 8 hours of the day. However, others have pushed to 20:4 or 23:1 regiment. Other approaches include fasting for 2 days of the week.
A study shows that fasting switches up the body’s metabolism. When fasting goes on for more than 12 hours, glycogen levels drop and the body looks to fatty acids for fuel instead of glucose. As a result, the production of ketones is triggered and this is what is thought to be the key factor in the increased in health benefits.
Alison Mackey/Discover
Beta-hydroxybutyrate, better known as BHB is one type of ketone that floods the brain when a person is fasting. A study found that BHB in mice stimulates memory, learning and other processes at the cellular level. BHB also triggers the release of a protein called brain-derived neurotrophic factor (BDNF) which is important for learning, memory and improved mood.
Many believe fasting is just another fad diet. But Harvie believes it might be here to stay because the fasting lifestyle is flexible and people can choose a plan that best fits them. “But at the end of the day, a diet is only as good as the person who follows it,” says Harvie.
– Cindy Liu
