4:3 Fasting May Be Easier Than Daily Calorie Counting—Here’s How It Can Help You Lose Weight

Intermittent fasting is often touted for promoting weight loss, but the concept encompasses a wide range of specific methods. It’s not one-size-fits-all, as the most effective fasting schedule generally varies between individuals. However, certain formulas have shown greater results. Here, we take a look at the 4:3 fasting method for weight loss, why it’s so effective and how to get started. 

How does intermittent fasting work?

Intermittent fasting involves alternating periods of regular eating with periods of fasting (eating minimal to no food). Multiple versions of intermittent fasting exist, but those most commonly studied include alternate-day fasting (where one day you eat normally and the next you abstain from eating or eat very few calories) and 5:2 intermittent fasting (eating normally five days a week and fasting for the other two). There is also daily time-restricted eating, where participants often fast for 16 hours per day and eat only within an eight-hour allotment (known as 16:8 fasting). 

The 4:3 fasting method for weight loss

To practice 4:3 fasting, you would eat normally for four days per week and fast for three non-consecutive days. Fasting days may be a complete fast, meaning little to no calories and mostly water is consumed, or eating up to 700 calories a day, explains Jessica McAllister, RD, owner and lead dietitian at Dietitian Approved Nutrition, LLC. 

Research shows 4:3 fasting may lead to greater weight loss 

A small study published April 1 in the journal Annals of Internal Medicine indicates that 4:3 intermittent fasting may result in greater weight loss over one year compared to simply restricting your daily calorie intake. 

Participants in the 4:3 intermittent fasting group limited their calorie intake by 80 percent of their typical daily needs for three nonconsecutive days per week. During the remaining four days, they consumed their normal calories with a focus on healthy eating. 

Those in the daily calorie restriction group maintained a daily calorie goal that would lower their calorie consumption by 34.3 percent. Participants in both groups were encouraged to exercise for at least 300 minutes weekly.

At the study’s conclusion, researchers found that participants in the 4:3 intermittent fasting group lost an average of 7.6 percent of their body weight over the 12 months, while those in the calorie restriction group lost 5 percent.

How 4:3 fasting promotes weight loss

It’s important to note that the 4:3 method (and intermittent fasting in general) is not a quick fix for weight management, nor is it sustainable long-term for everyone. However, experts say it provides evidence-based value. 

It may be easier than calorie restriction 

While following a 4:3 fasting schedule, you only need to track your caloric intake for three days. On fasting days, the goal is to restrict your calorie intake by 80 percent from your normal intake. That means if you normally consume 2,000 calories a day, you would aim for 400 calories during your fasting period. During the other four days of the week, you are unrestricted, explains Mary Mosquera Cochran, RD at The Ohio State University Wexner Medical Center.

“With a daily calorie restriction, you have to track your food intake all day long, every day, which can get old quickly,” she says. “Some may find a 4:3 eating plan both easier to follow and more sustainable compared to implementing a daily calorie restriction. Being able to follow a plan consistently is one of the biggest keys to losing weight and keeping it off.”

It can create a calorie deficit 

Implementing fasting days can ultimately help create a caloric deficit, a key factor in weight loss, notes Melanie Murphy Richter, RDN at L-Nutra, Inc. Despite eating normally on the other days, the reduced calorie intake on fasting days helps lower your overall weekly calorie consumption, she says. 

It boosts metabolism 

Fasting activates several important metabolic processes, says Richter. This includes ketosis, where the body begins burning stored fat for energy, and insulin sensitivity, helping the body become more efficient at using glucose for fuel rather than storing it as fat. 

Additionally, research suggests that fasting over 72 hours supports autophagy, the body’s natural cellular clean-up process, which may contribute to improved metabolic and overall health, Richter notes. 

How to maximize the weight loss benefits of 4:3 fasting

It’s important not to overeat on non-fasting days, as this defeats the purpose of intermittent fasting, says McAllister. Your diet should still be healthy and incorporate lean proteins, whole grains, fruits and vegetables. If you choose to eat some calories on fasting days, she recommends fruits and veggies as an ideal way to add high-volume, low-calorie foods. 

Hydration is also crucial, adds Richter. It’s vital to keep up your intake of water, teas and electrolyte-rich fluids to support energy and cellular function, especially on fasting days, she says. 

“Incorporating anti-inflammatory foods like leafy greens, berries and omega-3-rich sources can also enhance the overall metabolic and longevity benefits of intermittent fasting,” Richter adds.