Ask the RD: Is Intermittent Fasting Really Helpful For Weight Loss?

Ask the RD: Is Intermittent Fasting Really Helpful For Weight Loss?

Trinh Le, MPH, RD
by Trinh Le, MPH, RD
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Ask the RD: Is Intermittent Fasting Really Helpful For Weight Loss?

Proponents of intermittent fasting say it can help regulate hormones and aid with fast, sustained weight loss. But will it work for you? Here, we explore the idea behind intermittent fasting and whether it’s an effective weight loss strategy.

What is intermittent fasting?

Intermittent fasting is more about when you eat rather than what you eat. A typical plan puts you on a scheduled fasting phase followed by a non-fasting phase. The former is where you may skip meals or eat significantly fewer calories to generate the energy deficit needed for weight loss. This allows more food flexibility and higher calorie goals in the latter phase.

A typical, calorie-restriction weight loss plan encourages a small daily restriction of 250–1,000 calories depending on how much weight you have to lose and how fast you want to lose it. While this may seem like a lot, it’s small compared to the thousands of calories slashed during the fasting phase of an intermittent fasting plan.

Is intermittent fasting effective for weight loss?

Intermittent fasting can be effective for weight loss although it’s not necessarily better than other methods, according to a 2015 review of 12 clinical trials. More recently, a 2017 randomized controlled trial of 100 healthy but obese adults found that after one year, weight loss was comparable between intermittent fasting and daily calorie restriction.

Choosing intermittent fasting over more traditional calorie restriction comes down to individual preference and biology. We are culturally conditioned to eat three square meals with snacks in between, but that doesn’t mean everyone thrives on this schedule. One person may claim skipping a meal gives them more energy while another goes hangry if they miss just one snack. Some people do better on daily calorie restriction because they like an incremental change and regular meals. Others may find daily restriction wears away their willpower, and they prefer intermittent fasting so they can front load their calorie restriction to just a few days.

How to Practice Intermittent Fasting Safely

Intermittent fasting can be a safe choice for weight loss, but it all depends on how you approach it and how your body responds. Fasting is not for everyone and you shouldn’t try intermittent fasting if you are pregnant, diabetic or healing from a traumatic event such as surgery. Critics of intermittent fasting also point out that all this emphasis on restriction can backfire and encourage bingeing and other disordered eating behaviors. Our physical and mental health histories are all different, so if you have trouble deciding whether intermittent fasting is for you, consult a healthcare professional. Generally speaking, though, there’s little evidence to say intermittent fasting isn’t safe for healthy adults who have a bit of weight to lose.

The human body is designed to deal with fasting. It did not evolve to have food every hour of the day. Fasting triggers hormonal changes that are beneficial for your body. When you fast, insulin levels drop, allowing your cells to release stored fat and use it more effectively. Fasting also stimulates a housekeeping process called “autophagy.” With no food around to process, your cells can use that spare time to remove damaged or misfolded proteins. It doesn’t matter if you choose intermittent fasting or daily calorie restriction, fasting for a few hours enables your body to fulfill this important task.

It’s important to note that fasting is not the same as starvation. Going for days without eating or eating a very low-calorie diet indefinitely is not safe.

3 Types of Intermittent Fasting

For those new to MyFitnessPal, daily calorie restriction may be easier since it’s the default setting and it’s no less effective than intermittent fasting. For those interested in giving intermittent fasting a try, here are three popular plans:

1

Alternate-Day Fasting

Also known as “eat stop eat,”  this plan involves fasting on 3–4 non-consecutive days per week. A 24-hour fasting phase is followed by a non-fasting day where you can eat as much as you’d like.

2

Modified Fasting

A 5:2 fasting plan means fasting on two non-consecutive days per week where you eat between 20–25% of your daily calorie needs. On non-fasting days you can eat normally.

3

Time-Restricted Eating

With the Lean Gains and the Warrior Diet, you fast anywhere from 8–20 hours per day. You can eat freely during your non-fasting hours. Scheduling fasting hours overnight can make this plan easier.

THE VERDICT

There’s no one-size-fits-all diet for weight loss. Intermittent fasting can be helpful, but first consider whether it fits into the lifestyle you want to lead. If you try fasting and it’s not for you, cutting calories the old-fashioned way can still help you lose weight. Listen to your body, and pick the plan that works for you. Regardless, don’t forget calorie quality matters, too. As you’re losing pounds, nourish your body with nutrient-dense foods including fruits, veggies, grains, lean proteins and healthy fats.

About the Author

Trinh Le, MPH, RD
Trinh Le, MPH, RD
Trinh is a registered dietitian by day, blogger at Fearless Food RD by night. She loves helping folks develop a better relationship with food, which includes lots of cooking, eating and learning about nutrition. When she’s not snapping mouthwatering shots of (mostly) healthy food, you can find Trinh HIIT-ing it at her local gym. For more, connect with her on FacebookInstagram and Pinterest.

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