The Math Behind Fasting
What time frame triggers this calorie-restricted signal to the body? An earlier analysis of intermittent fasting in the New England Journal of Medicinefound that fitting meals into six-or eight-hour windows is beneficial in reducing inflammation compared with a typical day of eating, but a 12-hour window is less so, says Mark Mattson, Ph.D., a coauthor of the study. (
Research On Intermittent Fasting Shows Health Benefits
Evidence from decades of animal and human research points to wide-ranging health benefits of intermittent fasting, according to an NIA-conducted review of the research, published in the New England Journal of Medicine. Still, more research is needed to determine whether intermittent fasting yields benefits or is even feasible for humans when practiced over the long term, such as for years.
Intermittent fasting is an eating pattern that includes hours or days of no or minimal food consumption without deprivation of essential nutrients. Commonly studied regimens include alternate day fasting, 5:2 intermittent fasting , and daily time-restricted feeding .
Hundreds of animal studies and scores of human clinical trials have shown that intermittent fasting can lead to improvements in health conditions such as obesity, diabetes, cardiovascular disease, cancers and neurological disorders. The evidence is less clear for lifespan effects. Animal studies have shown mixed results, with sex, food composition, age and genetics among the factors that influence longevity. Human trials have mainly involved relatively short-term interventions and so have not provided evidence of long-term health effects, including effects on lifespan.
The review authors are Rafael de Cabo, Ph.D., of NIAs Intramural Research Program , and Mark P. Mattson, Ph.D., formerly of NIAs IRP and currently a neuroscientist at the Johns Hopkins University School of Medicine.
Intermittent Fasting Study Shows No Difference From Low Calorie Diet
May 11, 2022
Devika Umashanker, MD
Like many dieting trends, intermittent fasting seems to work very well for some people, but a new study shows the practice is no more effective than other forms of dieting.
A recent study out of Southern Medical University in China, published in the New England Journal of Medicine, examined dieters who follow intermittent fasting, also called time-restricted eating, and only eat during defined spans of time , in comparison with other who follow a low-calorie diet and eat at any time of the day.
Results showed that the intermittent fasting group consumed about the same amount of calories as those on the low-calorie diet, and both groups of dieters lost weight an average of 14 to 18 pounds and saw improved body fat and lean body mass measurements. However, there was no statistically significant difference in the amount lost between the groups.
Devika Umashanker, MD, medical director of medical weight loss with Hartford HealthCare, said the benefit of intermittent or time-restricted fasting seems to be that it curbs an individuals the appetite, which can help them eat less.
In a separate study, researchers found that time-restricted eating lowers the level of ghrelin, a hunger hormone in the stomach, improves appetite control and increases fat-burning over a 24-hour period, Dr. Umashanker explained. However, the study was small, with only 22 participants, and further research is needed with a larger population.
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Intermittent Fasting Health Benefits
NEJM intermittent fasting review authors describe potential benefits of intermittent fasting on obesity, diabetes, cancer, cardiovascular diseases, and even neurodegenerative brain diseases.
According to the authors Rafael de Cabo and Mark Mattson, studies in mice and nonhuman primates show consistent effects of caloric restriction on the healthspan .
In humans, the review studies show that intermittent fasting can have a positive effect on obesity, insulin resistance, high cholesterol levels, high blood pressure, inflammation, among other conditions. It may also have a preventative effect on various disorders, including asthma, brain tumors, cognitive decline, and even rheumatoid arthritis.
Intermittent fasting is frequently accompanied by weight loss. Are benefits of IF the result of caloric restriction, weight loss, or the effect of ketosis? To answer these questions, authors discuss metabolic switching, stress resistance, and ketone bodies.
During periods of fasting, as glucose gets depleted, fat is broken down for energy. Liver makes ketone bodies from fatty acids and ketogenic amino acids. These ketone bodies are not only fuel for energy, but also are signaling molecules regulating the activity and expression of proteins and molecules which influence aging and health!
And, the ability to switch back and forth between glucose and fatty acids/ketones as a fuel source is called metabolic flexibility.
Wrapping It Up
What Can I Eat While Intermittent Fasting
During the times when youre not eating, water and zero-calorie beverages such as black coffee and tea are permitted.
And during your eating periods, eating normally does not mean going crazy. Youre not likely to lose weight or get healthier if you pack your feeding times with high-calorie junk food, super-sized fried items and treats.
But what Williams likes about intermittent fasting is that it allows for a range of different foods to be eaten and enjoyed. We want people to be mindful and take pleasure in eating good, nutritious food, she says. She adds that eating with others and sharing the mealtime experience adds satisfaction and supports good health.
Williams, like most nutrition experts, regards the Mediterranean diet as a good blueprint of what to eat, whether youre trying intermittent fasting or not. You can hardly go wrong when you pick complex, unrefined carbohydrates such as whole grains, leafy greens, healthy fats and lean protein.
Recommended Reading: When Can I Eat Intermittent Fasting
According To The New England Journal Of Medicine Intermittent Fasting Going Without Food For Long Hours Periodically Every Week Or Avoiding Food For Fixed Hours Every Day Could Work Wonders For Those With Obesity Diabetes And Cardiovascular Diseases
Unlike fad diets that call for the elimination of certain food groups like fats or carbohydrates, Intermittent Fasting is an eating pattern in which one has timely meals within an eating window and fast at other times. It does not put any restrictions on what one eats whether it is whole grains, vegetables, protein, or fruits in terms of quantity and quality in the eating window.
The basic principle of IF is to give the body time to digest food, and in the process, burn out excess body fat and hence, detox. It is considered more attuned to the bodys circadian rhythm, and therefore, beneficial.
According to the New England Journal of Medicine , intermittent fasting going without food for long hours periodically every week, or avoiding food for fixed hours every day could work wonders for those with obesity, diabetes, and cardiovascular diseases.
intermittent-fasting interventions ameliorate obesity, insulin resistance, dyslipidemia , hypertension, and inflammation. Intermittent fasting seems to confer health benefits to a greater extent than can be attributed just to a reduction in caloric intake, researchers from the Johns Hopkins University School of Medicine reported in NEJM.
Calorie Restricted Diet Added To Time
China: Time-restricted eating is an intermittent-fasting regimen that involves a shortened period of time for eating within each 24-hour period. It is a popular weight-loss strategy as it is simple to follow, which may enhance adherence.A regimen of time-restricted eating is not more beneficial than daily calorie restriction with regard to reduction in body fat, body weight, or metabolic…
China: Time-restricted eating is an intermittent-fasting regimen that involves a shortened period of time for eating within each 24-hour period. It is a popular weight-loss strategy as it is simple to follow, which may enhance adherence.
A regimen of time-restricted eating is not more beneficial than daily calorie restriction with regard to reduction in body fat, body weight, or metabolic risk factors in patients with obesity.
The study, published in the New England Journal of Medicine found that obese patients who followed a time-restricted diet in addition to calorie restriction did not significantly lose a greater amount of weight compared to people who adhered alone to a calorie-restricted diet.
Peizhen Zhang, Southern Medical University, Guangzhou, China, and colleagues aimed to evaluate long-term efficacy and safety of time-restricted eating for weight loss.
Salient findings of the study include:
Reference:
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Adding A Fasting Period To Cutting Calories Didnt Improve Results But Experts Say The Popular Approach Warrants More Study
Intermittent fasting as a means of losing weight has soared in popularity in recent years, but without definitive trials supporting the approach. Now a new small, randomized trial may only serve to muddy the waters, with experts saying it fails to offer conclusive answers about time-restricted eating as a way to lose weight.
The study, led by Deying Liu, MD , showed that people with obesity who reduced their daily calorie intake by 25% did not boost weight loss by also adhering to an intermittent-fasting regimen that confined eating to an 8-hour window each day.
Mean weight loss at 1 year was 8.0 kg among those who restricted when they ate and 6.3 kg among those who ate throughout the day, a nonsignificant difference . The proportions of participants who had a weight loss of more than 5%, 10%, or 15% didnt differ between groups, the researchers report in the April 21, 2022, issue of the New England Journal of Medicine.
Moreover, intermittent fasting did not provide any benefits in terms of other measures of body composition and cardiometabolic risk.
Our data suggest that caloric intake restriction explained most of the beneficial effects of a time-restricted eating regimen, the authors write. However, our results support a strategy of time-restricted eating combined with caloric intake restriction as a viable and sustainable approach for obesity management.
I think it was not an informative study, Mozaffarian stated.
A Dearth of Evidence
The Need for Better Studies
Effects Of Intermittent Fasting On Health Aging And Disease
- The New England Journal of Medicine
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Recommended Reading: What’s Better Intermittent Fasting Or Keto
Does Intermittent Fasting Work A Registered Dietitian Weighs In
| Date Posted: 7/12/2022
PINEHURST, N.C. — If youve been looking for a way to manage your weight, you may have wondered what all the hype is about intermittent fastingand whether it actually works.
Intermittent fasting focuses more on when you eat rather than what you eat. Unlike other diets that count calories or eliminate certain food groups, this eating method allows you to eat what you want but restricts when you can eat.
Youll only eat during specific times of the day or week if you decide to do intermittent fasting. There are many different eating schedules you can follow. Some of the more popular approaches involve:
- Eating only during a 6- to 8-hour period each day
- Eating regularly 5 days a week but only eating one meal on the other 2 days
- Alternating days of regular eating with days where you eat less than 600 calories
The two biggest questions about this type of eating plan are related to whether it works and if its a healthy way to eat. Michelle Cole, RDN, CDCES, the program manager of FirstHealths Diabetes and Nutrition Education Center, said intermittent fasting can be a great tool for weight loss but may not work for everyone.
The most important thing to keep in mind with any diet is that fat loss, ultimately, requires a caloric deficit. Intermittent fasting can lead to a caloric deficit for people who may tend to snack in the evenings, for example, she said. Cole has some answers to these common questions about intermittent fasting.
Intermittent Fasting And Please Dont Just Read The Abstract
- Medical Category:Endocrine, Metabolic, Fluid, and Electrolytes
Background: There are many lifestyle modification strategies available as a way to aid in weight management. Two in particular include calorie restriction and intermittent fasting. Caloric restriction is self-explanatory, however personal experience has been it can be difficult to maintain for long durations of time. Intermittent fasting is a regimen that entails a shortened period of time for eating within a 24-hour period. It is simple to follow which may make it easier to sustain for longer periods of time.
Paper: Liu D et al. Calorie Restriction with or without Time-Restricted Eating in Weight Loss. NEJM 2022. PMID: 35443107
Clinical Question: Does a time restricted + calorie restriction diet reduce body weight at 12 months when compared to a calorie restriction diet alone?
Also Check: How To Use Intermittent Fasting
How Does Intermittent Fasting Work
There are several different ways to do intermittent fasting, but they are all based on choosing regular time periods to eat and fast. For instance, you might try eating only during an eight-hour period each day and fast for the remainder. Or you might choose to eat only one meal a day two days a week. There are many different intermittent fasting schedules.
Mattson says that after hours without food, the body exhausts its sugar stores and starts burning fat. He refers to this as metabolic switching.
Intermittent fasting contrasts with the normal eating pattern for most Americans, who eat throughout their waking hours, Mattson says. If someone is eating three meals a day, plus snacks, and theyre not exercising, then every time they eat, theyre running on those calories and not burning their fat stores.
Intermittent fasting works by prolonging the period when your body has burned through the calories consumed during your last meal and begins burning fat.
Intermittent Fasting: Live Fast Live Longer
The Benefits of Intermittent FastingCredit: Johns Hopkins Medicine
For many people, the New Year is a time to adopt new habits as a renewed commitment to personal health. Newly enthusiastic fitness buffs pack into gyms and grocery stores are filled with shoppers eager to try out new diets.
But, does scientific evidence support the claims made for these diets? In a review article published in the Dec. 26 issue of The New England Journal of Medicine, Johns Hopkins Medicine neuroscientist , concludes that intermittent fasting does.
Mattson, who has studied the health impact of intermittent fasting for 25 years, and adopted it himself about 20 years ago, writes that intermittent fasting could be part of a healthy lifestyle. A professor of neuroscience at the Johns Hopkins University School of Medicine, Mattson says his new article is intended to help clarify the science and clinical applications of intermittent fasting in ways that may help physicians guide patients who want to try it.
Intermittent fasting diets, he says, fall generally into two categories: daily time-restricted feeding, which narrows eating times to 68 hours per day, and so-called 5:2 intermittent fasting, in which people limit themselves to one moderate-sized meal two days each week.
In the article, Mattson notes that four studies in both animals and people found intermittent fasting also decreased blood pressure, blood lipid levels and resting heart rates.
Also Check: How To Properly Begin Intermittent Fasting
Intermittent Fasting And Its Effects On The Brain
As intermittent fasting has risen in popularity over the last decade, researchers have been exploring its long-term effects on physical health. Dr. Mark Mattson joins to discuss his research on metabolic switching, caloric restrictions, and the cognitive benefits from intermittent fasting. Guest: Mark P. Mattson, PhD, Johns Hopkins University School of Medicine, Department of Neurology
Episode Topics:
- How long does it take for a metabolic switch? 2:02
- How is this process different from normal dietary recommendations? 3:44
- What did you find in your research on the effects of intermittent fasting on health? 5:36
- Are there cognitive benefits to intermittent fasting? 8:12
- Can intermittent fasting and caloric restrictions improve the brains health? 9:49
- How does our modern lifestyles affect our brain and overall health? 16:07
- Is there any evidence that one way of intermittent fasting is better?17:54
- Are there any long-term consequences of intermittent fasting? 20:30
- What do you do in your life to improve your brain health? 22:39
Subscribe to this podcast through Apple Podcasts, Spotify, Podbean, or Stitcher, or wherever you get your podcasts.
What Is Intermittent Fasting
Many diets focus on what to eat, but intermittent fasting is all about when you eat.
With intermittent fasting, you only eat during a specific time. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help your body burn fat. And scientific evidence points to some health benefits, as well.
Johns Hopkins neuroscientist , has studied intermittent fasting for 25 years. He says that our bodies have evolved to be able to go without food for many hours, or even several days or longer. In prehistoric times, before humans learned to farm, they were hunters and gatherers who evolved to survive and thrive for long periods without eating. They had to: It took a lot of time and energy to hunt game and gather nuts and berries.
Even 50 years ago, it was easier to maintain a healthy weight. Johns Hopkins dietitian Christie Williams, M.S., R.D.N., explains: There were no computers, and TV shows turned off at 11 p.m. people stopped eating because they went to bed. Portions were much smaller. More people worked and played outside and, in general, got more exercise.
Nowadays, TV, the internet and other entertainment are available 24/7. We stay awake for longer hours to catch our favorite shows, play games and chat online. Were sitting and snacking all day and most of the night.
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