The Transformative Power of Time-Restricted Eating for Metabolic Syndrome
More than one-third of adults in the United States have metabolic syndrome, a combination of conditions that significantly increases the risk of heart disease, stroke, and type 2 diabetes. These conditions include high blood pressure, elevated blood sugar, excess abdominal fat, and abnormal cholesterol levels.
In a groundbreaking clinical trial conducted by researchers at the Salk Institute and University of California San Diego School of Medicine, time-restricted eating, also known as intermittent fasting, has shown remarkable potential in offering significant health benefits to individuals with metabolic syndrome. Patients who followed a consistent eight-to-ten-hour eating window each day for three months experienced improvements in various markers of blood sugar regulation and metabolic function compared to those who received standard treatments.
“Our bodies metabolize sugars and fats differently depending on the time of day,” explains Salk Professor Satchidananda Panda, co-corresponding author of the study. “By embracing time-restricted eating, we are tapping into the body’s natural rhythms to enhance metabolism and promote better health.”
The TIMET study, published in the prestigious Annals of Internal Medicine on September 30, 2024, is the first to assess the benefits of personalized time-restricted eating schedules in individuals with metabolic syndrome who are already on medication. According to co-corresponding author Pam Taub, a professor of medicine at UC San Diego School of Medicine and cardiologist at UC San Diego Health, metabolic syndrome often serves as a precursor to severe illnesses like diabetes and heart disease, underscoring the urgent need for accessible, effective lifestyle interventions.
With the prevalence of metabolic dysfunctions on the rise, largely attributed to unhealthy diets and sedentary lifestyles, conventional recommendations of “eat less, move more” have proven challenging for many individuals to sustain over the long term. In contrast, time-restricted eating offers a practical and sustainable approach that is accessible to a broad range of patients, including those already on medication.
“Unlike costly pharmaceutical interventions that necessitate lifelong use, time-restricted eating is a simple and side-effect-free lifestyle change that can be maintained indefinitely,” notes first author Emily Manoogian, a staff scientist at Salk. “Patients appreciate the fact that they are not required to alter what they eat, but rather when they eat.”
During the study, participants were assigned personalized time-restricted eating protocols based on their individual eating habits, sleep patterns, and daily commitments. By narrowing their eating window to a consistent eight to ten hours per day, starting at least one hour after waking up and ending at least three hours before bedtime, participants found the regimen manageable and more accommodating compared to the rigid time constraints typically imposed in other intermittent fasting studies.
What sets the TIMET study apart is its inclusion of participants who were already taking medications for metabolic syndrome, a population traditionally excluded from such trials. This has allowed the researchers to evaluate the additional benefits of time-restricted eating alongside standard-of-care pharmacological treatments.
During the three-month study period, 108 adults with metabolic syndrome were randomly assigned to either the time-restricted eating group or the control group. Both groups continued to receive standard-of-care treatments, including nutritional guidance on the Mediterranean diet, and utilized the myCircadianClock mobile app developed by Salk to track their meals.
At the end of the trial, participants who adhered to the time-restricted eating protocol exhibited improvements in key markers of cardiometabolic health, including blood sugar and cholesterol levels. They also manifested lower hemoglobin A1c levels, indicating enhanced long-term blood sugar management comparable to more intensive interventions set by the National Diabetes Prevention Program.
Moreover, the time-restricted eating group experienced 3-4% greater reductions in body weight, body mass index (BMI), and abdominal trunk fat, a type of fat closely associated with metabolic issues. Notably, these individuals did not experience significant loss of lean muscle mass, a common concern with weight loss efforts.
The TIMET trial contributes to the growing body of evidence supporting time-restricted eating as a viable, cost-effective intervention for improving cardiometabolic health. The promising outcomes suggest that healthcare providers may consider recommending this lifestyle intervention to patients with metabolic syndrome as a complement to existing treatments, although additional long-term studies are required to ascertain the sustained benefits and potential reduction of chronic disease risk.
The study was conducted by a team of researchers, including Monica O’Neal, Kyla Laing, and Nikko R. Gutierrez from Salk, and Michael J. Wilkinson, Justina Nguyen, David Van, Ashley Rosander, Aryana Pazargadi, Jason G. Fleischer, and Shahrokh Golshan from UC San Diego. Funding for the research was provided by the National Institutes of Health, the Robert Wood Johnson Foundation, and the Larry L. Hillblom Foundation Postdoctoral Fellowship.
