Bier said that intermittent fasting essentially means “taking a break from consuming energy” through food and drink on a regular basis. While the concept isn’t new, fasting has gained increased attention over the past decade after it was suggested that some of the benefits of calorie restriction in lab animals may be linked to prolonged fasting.
“Rodents fed a high fat food but allowed to eat only during their normal nighttime feeding hours were healthier and less likely to develop obesity or diabetes than their counterparts who had access to the high fat food. all day and night, even though they ate the same amount, ”she said.
While there are many different styles of intermittent fasting, the most popular is time-limited eating, according to Cortelezzi, in which eating is limited to a specific time (often eight hours) during the day and “fasting” by the night is extended beyond 12 hours.
Other forms include alternate-day fasting, where a person eats every alternate day and fasts for a full day in between, and modified fasting, where a person eats on these days of fasting but the calories are considerably restricted. The most common form of the latter is the 5: 2 diet, with five days of regular eating and two non-consecutive days of 800 calories or less.
Higher quit rates, dieticians noted, tend to be associated with longer periods of calorie restriction, which is why the 16-hour fasting model has gained momentum.
“Limiting your meals to an eight hour period during the day is the version that seems to show benefits like weight loss, but is still achievable, more than an 18 or 20 hour fast,” Bier said.
And she and Cortelezzi cautioned, fasting diets don’t remove the need for healthy eating and being active.
“It doesn’t mean you have eight hours, for example, to eat or do whatever you want,” Cortelezzi said. “If you eat a lot of processed foods and don’t exercise that calorie restriction probably won’t be as beneficial for weight loss.”