Key TakeawaysIntermittent fasting (IF) is one of the most popular eating patterns among Americans who follow a diet or eating pattern.IF doesn’t restrict what you can eat, only when you can eat.Some studies have shown that IF can help manage weight, reduce blood pressure, and lower cholesterol, but the evidence of long-term benefits is limited.

Key Takeaways

Intermittent fasting (IF) is one of the most popular eating patterns among Americans who follow a diet or eating pattern.IF doesn’t restrict what you can eat, only when you can eat.Some studies have shown that IF can help manage weight, reduce blood pressure, and lower cholesterol, but the evidence of long-term benefits is limited.

Intermittent fasting (IF) remains one of the most popular eating patterns among Americans following a diet plan, even though its long-term benefits are still unknown.

It’s a method of calorie restriction based on timing. Unlike other eating patterns, IF is based on when you eat, not what you eat.

“According to the internet, it can solve everything, right?” Susie said.

The research on IF is mixed. A new study showed that time-restricted eating may help people with obesity lose weight,while another found that intermittent fasting had no significant impact on weight loss.

Most of the other existing studies that support this eating pattern were conducted on animals, while the few studies involving humans have been short and often include a small sample size.

“We want to be careful,” Susie said. “The research is just pretty limited.”

Intermittent Fasting Plans

Although the research on IF is mixed, some people still follow a schedule to support their weight loss goals or to maintain their fitness level.

There are threemain IF schedules:

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Flexibility in Intermittent Fasting

The ability to individualize this eating pattern may be one reason it’s so popular compared to other restrictive diet plans.

Carianne Hixson, an administrative and creative coordinator based in Montclair, New Jersey, started trying intermittent fasting in 2019. She now follows a time-restricted fasting schedule where her “eating window” is between 11 a.m. and 7 p.m.

“I chose my window of eating based on my work schedule and my relationship with myself,” Hixson told Verywell.

Justin Kilgore, PT, DPT, a physical therapist based in Fort Collins, Colorado, has followed a time-restricted schedule on and off for the past six years. He said this eating pattern made sense with his work schedule and “natural eating tendencies,” but traveling can make it challenging to adhere to the schedule.

“I have experienced times where I have missed my eating window,” Kilgore said. “During those times, I’ll eitherbreak my fastfor the day, or I’ll switch to a 24-hour fast then return to normal the next day.”

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Is Intermittent Fasting Safe?

For most healthy adults, time-restricted eating is safe. IF can help people “become more cognizant of a healthy eating pattern,” but they do have to be cautious about how they practice it, said Sharon Smalling, MPH, RD, LD, a clinical dietitian specialist at the Memorial Hermann Hospital in Texas.

Although IF doesn’t restrict food choices, it’s still important to consider your overall diet quality.

“If you don’t change your food choices, it’s really not going to make any difference,” Smalling said.

People with certain conditions, such asdiabetes, should consider talking to a trusted healthcare provider before trying out IF, she added. For people who useinsulin, fasting might lead tohypoglycemia, a condition that occurs when blood sugar level drops too low.

According to Susie, IF is not recommended for children or people who are pregnant or breastfeeding. Some experts are also cautious about alternate-day and modified fasting schedules because these plans could lead to decreased concentration, low energy levels, or hunger pains.

For now, Smalling said, a lot more long-term research needs to be done to confirm the benefits of this eating pattern.

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What This Means For YouIf you have a history of disordered eating, IF may not be the right eating plan for you. Speak with a healthcare provider to evaluate your health history before getting on an IF schedule.

What This Means For You

If you have a history of disordered eating, IF may not be the right eating plan for you. Speak with a healthcare provider to evaluate your health history before getting on an IF schedule.

5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Jamshed H, Steger FL, Bryan DR, et al.Effectiveness of early time-restricted eating for weight loss, fat loss, and cardiometabolic health in adults with obesity: a randomized clinical trial.JAMA Intern Med. Published online August 8, 2022. doi:10.1001/jamainternmed.2022.3050Liu D, Huang Y, Huang C, et al.Calorie restriction with or without time-restricted eating in weight loss.N Engl J Med. 2022;386(16):1495-1504. doi:10.1056/NEJMoa2114833Stockman MC, Thomas D, Burke J, Apovian CM.Intermittent fasting: is the wait worth the weight?Curr Obes Rep. 2018;7(2):172-185. doi:10.1007/s13679-018-0308-9Academy of Nutrition and Dietetics.What is intermittent fasting?Freire R.Scientific evidence of diets for weight loss: different macronutrient composition, intermittent fasting, and popular diets.Nutrition. 2020;69:110549. doi:10.1016/j.nut.2019.07.001

5 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Jamshed H, Steger FL, Bryan DR, et al.Effectiveness of early time-restricted eating for weight loss, fat loss, and cardiometabolic health in adults with obesity: a randomized clinical trial.JAMA Intern Med. Published online August 8, 2022. doi:10.1001/jamainternmed.2022.3050Liu D, Huang Y, Huang C, et al.Calorie restriction with or without time-restricted eating in weight loss.N Engl J Med. 2022;386(16):1495-1504. doi:10.1056/NEJMoa2114833Stockman MC, Thomas D, Burke J, Apovian CM.Intermittent fasting: is the wait worth the weight?Curr Obes Rep. 2018;7(2):172-185. doi:10.1007/s13679-018-0308-9Academy of Nutrition and Dietetics.What is intermittent fasting?Freire R.Scientific evidence of diets for weight loss: different macronutrient composition, intermittent fasting, and popular diets.Nutrition. 2020;69:110549. doi:10.1016/j.nut.2019.07.001

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Jamshed H, Steger FL, Bryan DR, et al.Effectiveness of early time-restricted eating for weight loss, fat loss, and cardiometabolic health in adults with obesity: a randomized clinical trial.JAMA Intern Med. Published online August 8, 2022. doi:10.1001/jamainternmed.2022.3050Liu D, Huang Y, Huang C, et al.Calorie restriction with or without time-restricted eating in weight loss.N Engl J Med. 2022;386(16):1495-1504. doi:10.1056/NEJMoa2114833Stockman MC, Thomas D, Burke J, Apovian CM.Intermittent fasting: is the wait worth the weight?Curr Obes Rep. 2018;7(2):172-185. doi:10.1007/s13679-018-0308-9Academy of Nutrition and Dietetics.What is intermittent fasting?Freire R.Scientific evidence of diets for weight loss: different macronutrient composition, intermittent fasting, and popular diets.Nutrition. 2020;69:110549. doi:10.1016/j.nut.2019.07.001

Jamshed H, Steger FL, Bryan DR, et al.Effectiveness of early time-restricted eating for weight loss, fat loss, and cardiometabolic health in adults with obesity: a randomized clinical trial.JAMA Intern Med. Published online August 8, 2022. doi:10.1001/jamainternmed.2022.3050

Liu D, Huang Y, Huang C, et al.Calorie restriction with or without time-restricted eating in weight loss.N Engl J Med. 2022;386(16):1495-1504. doi:10.1056/NEJMoa2114833

Stockman MC, Thomas D, Burke J, Apovian CM.Intermittent fasting: is the wait worth the weight?Curr Obes Rep. 2018;7(2):172-185. doi:10.1007/s13679-018-0308-9

Academy of Nutrition and Dietetics.What is intermittent fasting?

Freire R.Scientific evidence of diets for weight loss: different macronutrient composition, intermittent fasting, and popular diets.Nutrition. 2020;69:110549. doi:10.1016/j.nut.2019.07.001

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