Restricting eating to a daily 10-hour window could help ward off diabetes and heart disease in people with metabolic disorders
Instead of counties calories, eating and drinking all the daily calories within a consistent 10-hour window could be a new way to fight obesity and diabetes in people with metabolic diseases.
In a small clinical study, researchers from the Salk Institute and the University of California San Diego School of Medicine found that a 10-hour time-restricted eating, when combined with traditional medications, resulted in weight loss, reduced abdominal fat, lower blood pressure and cholesterol, and more stable blood sugar and insulin levels for participants.
The 10-hour time-restricted eating (TRE) limits daily dietary intake to a consistent 10-hour window, creating a 14-hour nightly fast.
According to Satchin Panda, a professor in Salk's Regulatory Biology Laboratory, while people with obesity, high blood sugar, high blood pressure or high cholesterol are often advised to eat less and move more, their research suggests there is now another simple tool to fight off these diseases: restricting your eating time to a daily 10-hour window.
"For example, a person can have the first bite of the day or the first sip of tea at 8 am and should finish dinner by 6 pm. Animal and human studies have shown that this approach without an overt attempt to reduce calories or changing what one eats, can improve health. Medications and water are allowed outside the 10-hours' window," Panda told MEA WorldWide (MEAWW).
Metabolic syndrome -- which refers to a group of conditions, or metabolic disorders, or risk factors that increases a person's chances for developing heart disease, stroke, and type 2 diabetes -- affects nearly 30% of the US population, says the study.
The current treatment requires weight loss and lifestyle changes, such as adopting a healthy diet and increasing physical exercise, which are challenging and difficult to maintain. Even when combined with medication, such interventions are often insufficient to manage the disease entirely, say experts.
The pilot study, says the research team, could lead to a new treatment option for metabolic syndrome patients who are at risk for developing life-altering and costly medical conditions such as diabetes.
Stating that it is an easy and cost-effective method for reducing symptoms of metabolic syndrome and improving health, Panda says by delaying the onset of diabetes by even one year in a million people with prediabetes, the intervention could save roughly 9.6 billion dollars in healthcare costs.
"We have found that combining time-restricted eating with medications can give metabolic syndrome patients the ability to better manage their disease. Unlike counting calories, it is a simple dietary intervention to incorporate, and we found that participants were able to keep the eating schedule," says Panda.
The researchers are currently conducting a clinical trial funded by the National Institute of Diabetes and Digestive and Kidney Diseases to examine the benefits of time-restricted eating in a larger group of over 100 participants with metabolic syndrome.
The analysis
The researchers have been exploring the effects of the timing of nutrition on health in studies. Results from flies and mice led them to test the idea of time-restricted eating in healthy people. Studies lasting more than a year showed that time-restricted eating was safe among healthy individuals. Next, they examined it in patients with metabolic syndrome.
"We were curious to see if this approach, which had a profound impact on obese and diabetic lab rats, can help millions of patients who suffer from early signs of diabetes, high blood pressure, and unhealthy blood cholesterol," says the team.
Thirty-five participants were enrolled. After screening to meet eligibility criteria, 25 began the TRE intervention. The final analysis included 19 participants (13 men and 6 women) diagnosed with metabolic syndrome who self-reported eating during a time window of more than 14 hours per day. Additionally, 84% of participants were taking at least one medication, such as a statin or an anti-hypertensive therapy.
The team recruited patients from UC San Diego clinics who met at least three out of five criteria for metabolic syndrome: obesity, high blood sugar, high blood pressure, high level of bad cholesterol, and low level of good cholesterol.
The patients used a research app called myCircadianClock, developed in Panda's lab, to log every calorie they consumed for two weeks, followed by the three-month, 10-hour time-restricted eating intervention. Nearly 86% of participants correctly logged their food using the app, indicating high compliance throughout the study.
Participants did not report any adverse effects during the intervention. To reduce food intake to the 10-hour window, most participants delayed their first meal and advanced their last meal each day, so meals were not skipped. They chose to begin their 10-hour eating window between 8 am and 10 am and end the eating window between 6 pm and 8 pm.
Although calories were not recommended to be reduced for the intervention, some participants did report eating less, likely due to the shorter eating window.
"After 12 weeks, the volunteers returned to the clinic for a thorough medical examination and blood tests. We compared their final results with those from their initial visit. The results were pleasantly surprising," say researchers.
The team found that participants experienced improved sleep as well as a 3-4% reduction in body weight, body mass index, abdominal fat, and waist circumference. Nearly two-thirds of patients reported restful sleep at night and less hunger at bedtime.
Major risk factors for heart disease were diminished as participants showed reduced blood pressure and total cholesterol. Blood sugar levels and insulin levels also showed a trend toward improvement. All of these benefits happened without any change in physical activity or without decreasing calories.
"Eating and drinking everything (except water) within a consistent 10-hour window allows your body to rest and restore for 14 hours at night. Your body can also anticipate when you will eat so it can prepare to optimize metabolism," says Emily Manoogian, a postdoctoral fellow in Panda's lab.
Reducing the time window of eating also had several inadvertent benefits. On average, patients reduced their daily caloric intake by a modest 8%.
"TRE led to weight loss, healthier body composition (including decreased waist circumference), lower blood pressure and levels of cardiovascular disease-promoting lipids (that is, 'bad cholesterol levels), and more restful sleep. TRE could be an effective dietary intervention to help those with metabolic syndrome," says the study published in Cell Metabolism.
According to Panda, 10-hour TRE can be incorporated by many people. "For those with a long commute to work, they may consider taking their breakfast to work and eating it there. We have not yet done any animal or human studies to test how such 10-hour TRE can be incorporated among shift workers," Panda told MEAWW.
The researchers say despite the success of this study, time-restricted eating is not currently a standard recommendation from doctors to their patients who have metabolic syndrome.
"More rigorous randomized control trials and multiple location trials are necessary next steps. Toward that goal, we have started a larger study on metabolic syndrome patients," say researchers.