More than one-third of adults in the United States suffer from metabolic syndrome, a set of conditions that significantly increase a person’s risk of heart disease, stroke, and type 2 diabetes. These conditions include high blood pressure, high blood sugar, blood, excess abdominal fat and abnormal cholesterol levels.
In a new clinical trial, researchers from the Salk Institute and the University of California, San Diego School of Medicine found that time-restricted eating, also known as intermittent fasting, could offer important health benefits for adults with metabolic syndrome. Patients who ate within a consistent period of eight to ten hours each day for three months saw improvements in several markers of blood sugar regulation and metabolic function compared to those who received standard treatments.
“Our bodies actually process sugars and fats very differently depending on the time of day,” says Salk Professor Satchidananda Panda, co-corresponding author of the study and holder of the Rita and Richard Atkinson Chair. “By time-restricted eating, we are reclaiming the body’s natural wisdom and harnessing its daily rhythms to restore metabolism and improve health.”
The TIMET study is the first to evaluate the benefits of a personalized, time-restricted eating schedule in patients taking medications for metabolic syndrome. The results were published on September 30, 2024, in Annals of internal medicine.
“For many patients, metabolic syndrome is the tipping point that leads to serious, chronic diseases like diabetes and heart disease,” says co-author Pam Taub, professor of medicine at UC San Diego School of Medicine and cardiologist at UC San Diego. Diego. Diego Salud. “There is an urgent need for more effective lifestyle interventions that are accessible, affordable and sustainable for the average American.”
Western diets high in sugar, salt and fat, combined with increasingly sedentary lifestyles, are thought to have contributed to increased rates of metabolic dysfunction. While the initial recommendation may be to “eat less and move more,” these lifestyle changes are difficult to maintain long-term for most people. Researchers say time-restricted eating offers a more practical approach accessible to a broader range of patients, including those already taking medications.
“Unlike expensive pharmaceuticals like Ozempic, which require lifelong use, time-restricted eating is a simple lifestyle change that causes no side effects and can be maintained indefinitely,” says first author Emily Manoogian, a scientist at the Panda’s laboratory in Salk. “Patients appreciate that they don’t have to change that they eat, alone when they eat.”
In the new study, time-restricted feeding protocols were personalized to each participant’s eating habits, sleep-wake schedules, and personal commitments. The resulting regimen had them reduce their feeding period to a constant eight to ten hours per day, starting at least one hour after waking up and ending at least three hours before going to sleep. Manoogian says this personalized approach made the intervention easier for patients to complete, compared to other intermittent fasting studies, which typically assign the same strict time window to all participants.
The TIMET study also accepted participants taking medications for metabolic syndrome, a group typically excluded from such trials. This makes it the first study to measure the benefits of time-restricted eating in addition to existing standard drug treatments.
In the study, 108 adults with metabolic syndrome were randomly classified into the time-restricted feeding group or the control group. Both groups continued to receive standard treatments and received nutritional advice on the Mediterranean diet. Participants also recorded their meals using the myCircadianClock Mobile application, developed at Salk.
After three months, patients who had completed the time-restricted eating regimen showed improvements in key markers of cardiometabolic health, including blood sugar and cholesterol. They also observed lower levels of hemoglobin A1c, a marker of long-term blood sugar control. This reduction was similar in scale to what is typically achieved through more intensive interventions by the National Diabetes Prevention Program.
The time-restricted eating group also showed 3% to 4% greater reductions in body weight, body mass index (BMI), and abdominal trunk fat, a type of fat closely linked to metabolic diseases. . Importantly, these participants did not experience significant loss of lean muscle mass, which is often a concern with weight loss.
The TIMET trial adds to a growing body of evidence supporting the use of time-restricted feeding as a practical, low-cost intervention to improve cardiometabolic health. The promising results suggest that healthcare providers might consider recommending lifestyle intervention to patients with metabolic syndrome as an adjunct to existing treatments, although additional long-term studies are needed to determine whether time-restricted eating can maintain these benefits and ultimately reduce the risk of chronic disease.
Other authors include Monica O’Neal, Kyla Laing, and Nikko R. Gutiérrez of Salk, and Michael J. Wilkinson, Justina Nguyen, David Van, Ashley Rosander, Aryana Pazargadi, Jason G. Fleischer, and Shahrokh Golshan of UC San Diego.
The work was supported by the National Institutes of Health (R01DK118278, R01CA258221, P30CA014195, UL1TR001442), the Robert Wood Johnson Foundation (76014), and the Larry L. Hillblom Foundation Postdoctoral Fellowship.