by University of Illinois at Chicago
Nutrition
researchers at the University of Illinois Chicago studied 80 people
with nonalcoholic fatty liver disease and found that those who followed
an alternate-day fasting diet and exercised were able to improve their
health.
Publishing their findings in Cell Metabolism,
the researchers report that over a period of three months people who
exercised and alternated feast and fast days—eating without restriction
one day and eating 500 calories or fewer the next—saw increased insulin sensitivity and decreased liver fat, weight and ALT, or alanine transaminase enzymes, which are markers for liver disease.
Nonalcoholic
fatty liver disease is a buildup of fat and inflammation in patients
who drink little to no alcohol. Approximately 65% of obese adults have
the disease, and this condition is strongly related to the development
of insulin resistance and Type 2 diabetes. If left unchecked, fatty
liver disease can lead to more serious complications like cirrhosis or
liver failure, but there are limited good drug options for treating the
condition.
Study author Krista Varady called the findings "pretty amazing."
"When
we compared the results of our study groups, we saw clearly that the
most improved patients were in the group that followed the alternate-day
fasting diet and exercised five days a week," said Varady, professor of
nutrition at the College of Applied Health Sciences. "The people who
only dieted or only exercised did not see the same improvements, which
reinforces the importance of these two relatively inexpensive lifestyle
modifications on overall health and on combating chronic diseases like
fatty liver disease."
Participants in the clinical trial were randomized to one of four groups: an alternate-day fasting group, an aerobic exercise group, a combined group and a control group in which participants made no changes to their behaviors. Participants in the diet groups tracked their food intake and participants in the exercise groups used an elliptical machine in Varady's lab for one hour, five days a week.
Varady
said the study did not test if alternate-day fasting was better or
worse than other diets when combined with exercise, but she was
surprised to see very few participants drop out of the study.
"Alternate-day
fasting and exercise interventions can be difficult for people to stick
to and in prior studies we have seen significant dropout. It was very
interesting to see that in this trial we had very high adherence to the
interventions," said Varady, who thought the study's implementation at
the beginning of the COVID-19 pandemic in 2020 could be a plausible
explanation for the variation.
In
addition to seeing improved metabolic indicators, the study authors
also noted there were no serious safety events during the trial—the
patients were able to safely maintain the diet and exercise for the
three-month study, which Varady thinks is an indicator the intervention
may be a good option for people with fatty liver disease who want to
improve their health without pharmaceuticals, which can have side
effects.
In their paper, "Effect of alternate day fasting combined with aerobic exercise on non-alcoholic fatty liver disease: A randomized controlled trial," which is the first study to examine the effect of intermittent fasting combined with exercise on nonalcoholic fatty liver disease outcomes,
the authors write, "Our findings also indicate that the combination
intervention was effective for reducing body weight, fat mass, waist
circumference, ALT, fasting insulin, insulin resistance, and increasing
insulin sensitivity, among patients with obesity and NAFLD, versus
controls."
More information: Mark
Ezpeleta et al, Effect of alternate day fasting combined with aerobic
exercise on non-alcoholic fatty liver disease: A randomized controlled
trial, Cell Metabolism (2022). DOI: 10.1016/j.cmet.2022.12.001