In a nutshell, intermittent fasting (IF) is just that: fasting intermittently
It's limiting calorie intake during certain hours/day or days/week. In this respect, IF is more of an eating pattern than a diet. It limits when to eat, and not so much what to eat. And that’s part of it’s appeal to people who don’t want to count calories or follow a restrictive plan.
Fasting has been a practice throughout human evolution. Ancient hunter-gatherers didn't have supermarkets, refrigerators or food available year-round. Sometimes they couldn't find anything to eat.
We now have unlimited access to food (including junk food), so eating several meals per day plus snacks may be less natural than fasting from time to time.
There are lots of variations on Intermittent Fasting. They include:
The 16/8 method: This method involves skipping breakfast and restricting your daily eating period to 8 hours, such as 1–9 p.m.
5:2 days of fasting, where you eat regularly for five days of the week, then take in just 500-600 calories/day for the other two (non-consecutive) days
Eat-Stop-Eat: This involves fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day
Most people find the 16/8 method to be the simplest, most sustainable and easiest to stick to. It’s also the most popular.
Is intermittent fasting effective for weight loss?
Intermittent fasting can help to lose weight because it can help you to eat fewer calories, and burn more calories too.
Lots of people say they have success with it…….Here’s what the the studies say:
According to one review study, intermittent fasting helped people to lose 3-8% of their weight over 3-24 weeks. In this study, people also lost 4-7% of their waist circumference (i.e., belly fat).
Another study of 100 people with obesity showed that after a year, the people who fasted on alternate days lost more weight than people who didn’t change their eating pattern. But, (and here’s where it’s interesting) they didn’t lose any more weight than those on a calorie restricted diet. Out of the people who were to follow the intermittent fasting protocol, 38% of them dropped out.
Sticking with a diet is one of the keys to weight loss success. So, if you can’t stay with a weight-loss diet, you’re less likely to lose the weight and keep it off.
Before you consider intermittent fasting
Intermittent fasting is not for everyone. People who are underweight, or have eating disorders shouldn’t fast. Neither should women who are pregnant, trying to get pregnant, or are breastfeeding.
Certain medical conditions can be worsened with longer periods of fasting. Also, people taking certain medications can be prone to side effects with intermittent fasting as well.
There is still some controversy around whether or not intermittent fasting is right for women due to the risk of hormone imbalance. Until more concrete studies are available, it may be best to start with an intermittent fasting schedule that is less extreme. For example, women should aim for a 12 hour fasting window rather than a 15- to 16-hour window , an all-day fast or extreme low calorie days.
One of the reasons people drop out of the intermittent fasting eating pattern is that it’s hard to stick with the fasting part. They eat more than the allowed (low-level of) calories when they’re supposed to be fasting. And when they finish fasting, they may overindulge due to the reaction of the appetite hormones and hunger drive while fasting. None of these will help with weight loss.
Also, the hours and days of fasting can be very difficult. So having strong social support will be key to those intermittent periods of fasting. Sticking to a (healthy, nutrient-dense) weight loss diet is the key to success, and intermittent fasting can be difficult for many people to stick with.
Intermittent fasting is a weight loss trend that does work for some people. It can help to lose weight and reduce belly fat. But, it isn't healthy and safe for everyone. Many people should not try intermittent fasting because it can be risky. It can also be difficult to stick with.
For the best chance of long-term weight loss success, finding a diet, you can stick with is key.