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Limiting food intake with time does it work?

A new study asks whether eating a restricted diet has positive health effects. AleksandarNakic/Getty Images

• The results of animal research have revealed significant metabolic benefits from restricted eating.
• Initial human studies suggest that these findings could be useful to humans.
• A recent study looks at the evidence from both human and animal studies.
• The authors suggest additional research is needed to discover the ways in the way that restricted eating habits could be beneficial and achievable for humans.

Researchers have looked at the evidence supporting food choices that are healthy a time-restricted diet -it is a kind of intermittent fasting, in which individuals consume food only within the same time each day.

The review, which is released in the Journal of the Endocrine Society, Endocrine Reviews Researchers looked at studies on animals as well as the first human research. They found evidence that limiting time eating habits can aid in the prevention and treatment many chronic metabolic diseases.

However, they insist on more substantive research to demonstrate the positive effects of a time-restricted diet on food consumption on human beings, as well as to understand the mechanisms at the root of these benefits.

Circadian rhythm

The concept of time-restricted eating has attracted significant interest from researchers in the past few years. When eating is restricted due to time, people usually eat their usual diet but only for a set time frame each day. This could range from six to twelve hours.

Scientists have proved the advantages of eating a time-restricted diet, particularly in mice studies. There are however numerous tests with human participants that have produced positive results.

The author , who is in contact with Prof. Satchidananda Panda from the Regulatory Biology Laboratory at the Salk Institute for Biological Studies in San Diego, CA, was interviewed by Medical News Today. He said that time-restricted eating studies in animals have suggested that there are health benefits to eating food that is time-restricted for humans.

"Animal studies so far have revealed that eating restricted for a certain amount of time affects various organs, and even the microbiome of the gut in a positive way. Numerous pathways and molecules associated with metabolic disorders, like prediabetes and diabetes, adiposity [...], fat liver disease, as well as certain cancers, are controlled in a positive manner by eating with a time limit," prof. Panda.

According to the authors of the latest review one of the primary advantages of following a restrictive diet is the possibility of helping people restore their disturbed circadian rhythm.

Circadian rhythms are a series of bodily processes that function during a 24-hour periodTrusted Source. Professor. Panda and his coworkers observe that circadian rhythms developed as a result of fluctuations in light, temperature and humidity as well as the availability of nutrients over the cycle of the earth's night and day cycles.

In the event that someone has a change in their circadian rhythm it could lead to various health issues that include cancers, metabolic disorders, issues with the immune system, hormonal changes and reproductive issues.

Modern living may alter the circadian rhythm in different ways. As per Prof. Panda and his colleagues 40% of the population are employed, taking care of, and socialize into the late hours. This leads to the circadian rhythm to be disturbed.

A circadian rhythm, fasting

The primary cause for this disturbance could be an increase in consumption of food outside of the amount your body is used to, in line with your circadian rhythm, which is at night as opposed to during the daytime.

Professor. Panda and his colleagues discuss their findings regarding circadian cycles which are associated with peripheral organs and the majority of our brains predominantly affected by the timing of food intake.

In turn, restricting consumption of food with a set time that includes the overnight fasting time could aid in supporting your circadian rhythm and lessen the risk of adverse health effects from an imbalanced circadian rhythm could result.

Professor. Panda and his colleagues are also highlighting that mice studies show that time-restricted eating can decrease the amount of fat in the stomach and improve health.

Researchers are aware that there are small number of human studies examining the benefits of restricted diets. The initial findings of these studies are consistent with the positive outcomes observed in animal models, for example, a decrease in body weight and belly fat, waist circumference and the measurement of body mass.

Professor. Dorothy Sears from the Division of Endocrinology and Metabolism at the University of California San Diego School of Medicine also talked to MNT..

Professor. Sears is an expert on eating habits that are restricted by time in addition to the circadian cycle. She stated she believes Dr. Panda and his colleagues study "is a thorough review article that summarizes the accumulating evidence that alignment of food intake with the body's biological rhythms promotes health."

Ideal eating window?

The current research offers a hint of the best timing to reduce how much food eaten.

A conversation with MNT Professor. Panda said "The human studies have tested 4-, 6-, 8-, 10-, and 12-hour time-restricted eating, and these studies show some dose responses."

"Four- and 6-hour time-restricted eating can have many benefits among [people with overweight and obesity], but it also reduces quality of life due to its adverse effects on feeling excessive hunger, dizziness, headache, and nausea, etc."

"Eight- and 10-hour time-restricted eating windows are well tolerated, yield several benefits, and people voluntarily adopt such practices long term. "

"Twelve-hour time-restricted eating may not produce immediate benefits within a few months, but we do not know in the long term if it could impart some benefits."

As per Prof. Sears, "There is insufficient research evidence that supports any particular regimen, e.g., best time of day to start/stop eating or how many 'eating' hours per day."

"Promising evidence from Dr. Panda's lab in mice supports that an occasional 'day off' from time-restricted eating, or eating at night may still confer benefit in humans," Professor. Sears.MEDICAL NEWS Today's NEWSLETTERKnowledge can be a source of power. Subscribe to our weekly newsletter for free.

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However, Professor. Panda told the MNT that some people should seek advice from a physician before beginning any diet that is time-restricted.

"Most people and their caregivers believe that it's safe for everyone from teens to seniors to eat a restricted diet for 12 hours every day. Time-restricted eating for ten hours is possible for those who do not suffer from a chronic illness," stated Prof. Panda.

"For those suffering from type 1 diabetes or type 2 diabetes and other chronic diseases restricted eating for 10 hours or less [...] might require medical supervision to prevent hypoglycemia or medication adjustments. In the same way, those with other chronic illnesses should consult their doctor prior to starting eating for 8 or 10 hours. eating."

"Time-restricted eating for 6 or 4 hours is not recommended for the majority of people. A short time frame for eating could also result in a significant reduction in the daily intake of calories or the consumption of specific macro- or micronutrients. This type of restricted eating for short periods of time may be unsustainable over the long run," said Professor. Panda.

Professor. Sears confirmed this by saying in an interview with the MNT that "overall the time-restricted diet appears to be safe for the majority of people, not just those suffering from type 2 diabetes. ."

"Some patients report minor temporary side effects like lightheadedness or nausea. Due to the limited studies, self-reported compliance and the variety of regimens further research is required to evaluate these effects fully."

"People with conditions that impact metabolism -- for example, thyroid disorders, diabetes, and pregnancy -- should consult their healthcare provider before starting a regimen that includes fasting for longer than overnight," said Prof. Sears.

Future research

Professor. Panda told MNT that scientists must conduct more research to better understand the advantages of a time-restricted diet for both animals and human beings.

"Most restricted eating studies were conducted on male mice in their early years. We need to extend these studies to include both genders as well as older mice."

"Many benefits of eating restricted in time point to changes in the molecular structure of multiple organs, yet we don't know the nature of those changes. Therefore, more in-depth molecular studies across multiple organs are required to gain a better understanding of the mechanisms of eating restrictions on time."

"Although time-restricted eating may appear easy to adopt, many find it difficult [...] So implementation research on finding personal, interpersonal, cultural, work-related, and societal barriers to adopting time-restricted eating [is] needed," Professor. Panda.

Professor. Sears A larger, more robust studies are required to better know how to best implement the time-restricted diet.

Professor. Sears said"that "randomized controlled trials that are large in sample size are essential to accurately assess different times of food intake and the related health effects. The majority of controlled randomized studies have been limited to very few people, and therefore, the results from these studies are not reliable."

"There are several large trials now funded by the National Institutes of Health and the Department of Defense to test benefits of circadian-aligned food intake timing," added Professor. Sears. "Results from these should be illuminating and provide more statistically robust interpretations to guide public health recommendations."