Intermittent fasting (IF) is a very popular diet. Proponents say it can help you lose weight, lower cholesterol, blood pressure, improve blood-sugars, and slow aging. But is this all really true?
First Things First, What is Intermittent Fasting?
Intermittent fasting is an umbrella term that includes a wide variety of eating approaches, most of which fall into one of two categories: alternate-day fasting and restricted eating windows. Unlike other diets, it doesn’t restrict your food choices or intake. Instead, all that matters is when you eat.
Alternate day fasting involves switching back and forth between days when you eat more and days when you eat less. For example, someone might eat 800 calories or less on their fasting days and eat 2000+ calories on their feast days. This is also sometimes described as calorie cycling.
Restricted Eating Window
The other approach that’s very common is restricting the time you eat. Instead of restricting your food intake on certain days, you restrict the time you eat.
There are lots of variations on this approach. Some people follow a four-hour eating window, essentially eating just one big meal a day. Others might eat two to four meals within an eight or ten-hour window. For example, someone might start eating at 11 am and stop eating at 7 pm. (If you skip breakfast, you might already be doing this without even realizing it!)
Is Intermittent Fasting a Good Way to Lose Weight?
Although we keep hoping to discover a magic formula that allows us to lose weight without actually eating less, we haven’t found it yet. It all still comes down to calorie deficit.
The reason a person loses fat when doing the IF diet is that it puts them in a calorie deficit.
Think about it, if a person starts eating at 11 am and stops eating at 7 pm, that means they aren’t eating their typical 300+ calorie breakfast and 200+ calorie night time snack. That’s over 500+ calories they are no longer eating. Over the course of a week, that adds up to 1 pound of fat loss.
Note: there are 3,500 calories in one pound.
Intermittent fasting tends to lead to weight loss—but that’s because people following these regimens end up eating less. These approaches also can lead to improvements in body composition, cholesterol, and blood sugar metabolism but no more so than in people who lose weight through more traditional diets.
All diets have pros and cons, but when it comes to which is best for losing weight, it really boils down to which one works for you. Which diet is sustainable for your lifestyle.
There are a few groups for whom intermittent fasting may not be appropriate, including pregnant women and people with a history of eating disorders. Anyone using medications to manage their blood sugar should seek guidance from a nutrition or health professional before experimenting with any sort of fasting protocol.
But if you are not in any of those categories, and you need to lose weight, then this might be great for you. If you decide to experiment, or you have been experimenting with it already, I’d love to hear how it’s working for you, what you like about it, and how long you’ve been doing it.