Can you prevent diabetes with intermittent fasting? It can improve insulin sensitivity, pancreatic response to blood sugars, and even prevent prediabetes from turning into diabetes.
Every person is a unique individual with different metabolism, so there is not just one treatment for type 2 diabetes. Intermittent fasting has been around for a long time and has shown over many studies to have a number of benefits, especially in preventing diabetes.
In the most current study results, which included eight men with prediabetes, it was found that those who followed early time-restricted feeding — where all calories for the day are consumed by mid-afternoon and within eight hours or less — had improvements in insulin sensitivity and pancreatic response to elevated blood glucose, compared with those who ate meals over a 12-hour period, even when eating the same number of calories. The findings also revealed an association between the shorter, earlier eating pattern and a significant reduction in blood pressure, oxidative stress, and evening appetite levels.
For this study at the Pennington Biomedical Research Center, the results showed that eating all of one’s meals by mid-afternoon and fasting the rest of the day improves blood sugar control, blood pressure and oxidative stress, even when people don’t change what they eat.
“This is the first study in humans that shows consuming all of your calories in a six-hour period provides metabolic advantages compared to eating the exact same amount over 12 hours or more, even if you don’t lose weight,” said Dr. Eric Ravussin, associate executive director of Pennington Biomedical, director of the Nutrition Obesity Research Center, and one of the study’s co-authors.
The data also indicate that our feeding regimen has to be synchronized with the body’s circadian rhythm and biological clock.
Dr. Courtney Peterson, an adjunct assistant professor at Pennington Biomedical and an assistant professor at the University of Alabama at Birmingham, was the primary investigator on the study.
The research is important because it shows for the first time in humans that the benefits of intermittent fasting are not solely due to eating less. Practicing intermittent fasting has intrinsic benefits regardless of what you eat. Also, the study shows that eating early in the day may be a particularly beneficial form of intermittent fasting.
Peterson hopes that the research will also raise awareness of the role of the body’s internal biological clock — called the circadian system — in health.
We know that eating at night is bad for your metabolism. Our bodies are optimized to do certain things at certain times of the day and eating in sync with our circadian rhythms seems to improve our health in multiple ways. For instance, our body’s ability to keep our blood sugar under control is better in the morning than it is in the afternoon and the evening, so it makes sense to eat most of our food in the morning and early afternoon.
Previous studies showed intermittent fasting improves metabolism and health. However, researchers didn’t know whether these effects are simply because people ate less and lost weight.
They decided to conduct the first highly controlled study to determine whether the benefits of intermittent fasting are solely due to eating less. The study was also the first to test a form of intermittent fasting called early time-restricted feeding, or eTRF in humans. Early time-restricted feeding involves combining time-restricted feeding — a type of intermittent fasting where people eat in an 8-hour or shorter period each day — with eating early in the day to be in alignment with the body’s circadian rhythms in metabolism. It is tantamount to eating dinner in the mid-afternoon and then fasting for the rest of the day.
In the study, eight men with prediabetes tried following eTRF and eating at typical American meal times for five weeks each. On the eTRF schedule, the men each started breakfast between 6:30-8:30 am each morning, finished eating six hours later, and then fasted for the rest of the day — about 18 hours. Everyone finished dinner no later than 3 p.m. By contrast, on the typical American schedule, they ate their meals spread across a 12-hour period. The men ate the same foods on each schedule, and the researchers carefully monitored the men to make sure that they ate at the correct times and only ate the food that the researchers gave them.
The researchers found that eTRF improved insulin sensitivity, which reflects how quickly cells can take up blood sugar, and it also improved their pancreases’ ability to respond to rising blood sugar levels. The researchers also found that eTRF dramatically lowered the men’s blood pressure, as well as their oxidative stress levels and their appetite levels in the evening.
These findings could lead to better ways to help prevent type 2 diabetes and hypertension.
For more on intermittent fasting, see Intermittent Fasting and Its Beneficial Effects On The Body.
For Dr. Mark Mattson’s intermittent fasting video series and downloadable transcript, watch Dr. Mark Mattson Intermittent Fasting: What is it? Recommend it, an exclusive discussion with Diabetes in Control.
- Early time-restricted feeding (eTRF) increases insulin sensitivity.
- eTRF also improves β cell function and lowers blood pressure and oxidative stress.
- eTRF lowers the desire to eat in the evening, which may facilitate weight loss.
- Intermittent fasting may improve health even in the absence of weight loss.
The study, published in the journal Cell Metabolism, is now available online.