Fasting is more than a popular diet fad, according to a recently released University of Southern California Davis study. A five-day fast once a month could reduce one’s risk of life threatening diseases and result in weight loss. For 71 adults, participating in a fasting-mimicking” phase II trial at the USC Leonard Davis School of Gerontology, a low calorie diet reduced cardiovascular risk factors including blood pressure, signs of inflammation (measured by C-reactive protein levels), as well as fasting glucose and reduced levels of IGF-1, a hormone that affects metabolism. The five-day fast, once a month for 90 days, also resulted in smaller waistlines, weight loss and lower total body fat and trunk fat, but not reduced muscle mass.
The study, published in Science Translational Medicine (Feb 15, 2017), reduced the study participants’ risks for cancer, diabetes, heart disease and other age-related diseases. “This study provides evidence that people can experience significant health benefits through a periodic, fasting-mimicking diet that is designed to act on the aging process,” said Valter Longo, director of the USC Longevity Institute and a professor of biological sciences for USC Davis and Dornsife. “Prior studies have indicated a range of health benefits in mice, but this is the first randomized clinical trial with enough participants to demonstrate that the diet is feasible, effective and safe for humans.
Fasting Mimicking Study Results
The study participants were considered “at risk” because they exhibited risk factors such as high IGF-1, cholesterol, blood pressure or blood sugar levels. Each made significant progress toward better health in the following manner:
- Baseline fasting glucose levels for participants with high blood sugar levels (putting them at risk for diabetes) dropped into the healthy range, below 99 mg/dl — but these levels didn’t drop among participants who already had healthy levels at the beginning of the study.
- Cholesterol was reduced by 20 mg/dl in those with high cholesterol levels, and by about 5 mg/dl in all participants.
- Participants on the fasting-mimicking diet lost an average of about 6 pounds. Their waistlines shrank by 1 to 2 inches.
- Systolic blood pressure, which was in the normal range when the study began, dropped by 4.5 mmHG, while their diastolic blood pressure dropped by 3.1 mmHg.
- IGF-1 dropped to between 21.7 ng/mL and 46.2 ng/mL, reaching a range associated with lower cancer risk.
“Fasting seems to be the most beneficial for patients who have the great risk factors for disease, such as those who have high blood pressure or pre-diabetes or who are obese,” Longo said.
Fasting Study Methods
- One hundred people participated in the trial from April 2013 to July 2015.
- The participants, ages 20 to 70 and all generally healthy, were divided into two groups for the randomized trial.
- Participants in the first group, the control group, were asked to continue their normal eating habits for three months. People in the second group were placed on a three-month test of the fasting-mimicking diet.
- Those on the special diet were required to eat food products supplied by the nutrition company L-Nutra during the fasting periods of five days each month.
- The diet, which was designed to mimic the results of a water-only fast, allowed for participants to consume between 750 and 1,100 calories per day. The meals for the fast-mimicking diet contained precise proportions of proteins, fats and carbohydrates. For more on five-day fasting diet meal composition from Prolon, click here.
- After three months, participants in the control group were moved onto the special diet.
Longer Term Outcomes
The researchers invited participants in the study for one last set of tests three months later, at the end of the diet. They found that the beneficial effects — from weight loss, smaller waistlines and lower glucose, blood pressure and IGF-1 levels — were sustained.Longo noted that larger FDA studies are necessary to confirm its effects on disease prevention and treatment. The next step for researchers is a large, FDA phase III clinical trial to test the FMD on patients diagnosed with age-related diseases or at high risk for them. The researchers said further investigation will determine whether the benefits of the diet can continue for several months.
Min Wei, Valter D. Longo et al. Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease. Science Translational Medicine, 2017; 9 (377): eaai8700 DOI: 10.1126/scitranslmed.aai8700