Alternate Day Fasting with Exercise Improves Non-Alcoholic Fatty Liver Disease: NAFLD

The annual costs associated with the obesity and diabetes crisis world-wide are staggering and includes costs associated with doctors, medications, lost wages, etc. These health care costs could be significantly reduced, and the health of individuals significantly improved, through changes in lifestyle and diet. Both sound easy, but of course in the real world with real individuals these seemingly simple goals are often difficult, if not insurmountable.

As a means to address novel strategies aimed at the treatment of obesity, a recent study has examined non-pharmacological lifestyle strategies to treat non-alcoholic fatty liver disease (NAFLD) associated predominantly with obesity:

Effect of alternate day fasting combined with aerobic exercise on non-alcoholic fatty liver disease: A randomized controlled trial

It is important to understand the significance of NAFLD. Approximately 65% of adults with obesity have NAFLD, and this condition is strongly related to the development of insulin resistance and type 2 diabetes.

The study compared the effects of alternate day fasting (ADF) combined with exercise to fasting alone, or exercise alone, on the level of fat accumulation in the liver (referred to as intrahepatic triglyceride, IHTG), a hallmark of NAFLD.

What exactly is alternate day fasting? Although there are at least three distinct types of ADF diets the general then of these diets is that consume a minimum level of calories (considered to be 25% or less of normal daily caloric requirement) and alternate this with a day where they consume food as they desire. Some variations on these diets have an individual consume no food at all on the fast day. Other variations include the 5:2 diet where there are one or two fasting days per week. Regardless of the particular type of ADF one engages in the evidence is quite clear that these diets help with obesity, insulin resistance, dyslipidemia, hypertension, and inflammation. In addition, evidence has found that intermittent fasting is generally safe.

With respect to NAFLD evidence has already shown that moderate to vigorous intensity exercise alone, 3 to 5 days each week is associated with a 20%–30% relative reduction in hepatic steatosis (fatty liver). These studies also correlated physical activity with decreases in pro-inflammatory cytokines and markers of oxidative stress which, in turn, was demonstrated to improve liver enzyme profile. Of clinical significance is that exercise enhances hepatic and peripheral insulin sensitivity which is associated with a reduction in the progression of NAFLD and a reduction in cardiovascular disease risk. Physical activity can also improve quality of life, mood, and mental health in individuals with obesity and NAFLD.

Since prior studies had demonstrated that ADF could reduce the level of hepatic fat, liver enzymes in the blood, and body weight in individuals with NAFLD, the authors of this recent paper set out to ascertain if the addition of moderate exercise could result in even greater improvement in health. As stated, the study aimed to compare the effects of ADF combined with aerobic exercise, with ADF alone, or exercise alone, on IHTG content and metabolic risk factors in patients with NAFLD.

The outcomes of this particular trial demonstrated that ADF with exercise was better at reducing IHTG, body weight, and fat mass when compared to exercise alone. However, the results also demonstrated that the ADF and exercise regimen was not superior to fasting alone.

Examination of improvements in insulin resistance and insulin sensitivity, key measures of the risk for type 2 diabetes, showed that all three regimens showed similar levels of improvement. In other words, ADF plus exercise, fasting alone, or exercise alone, all produced similar levels of improvement in insulin functions and glycemic control.

One potentially significant negative outcome from this study was the finding that ADF plus exercise, fasting alone, or exercise alone did not significantly improve blood pressure, heart rate, nor circulating levels of blood lipids (LDL, HDL and triglycerides) when compared to the control (no ADF or exercise) participants in this study.

KEY TAKE HOME MESSAGE: Regardless of the last finding of this current study, there is ample evidence that body weight reductions of as little as 5%–10% can have profoundly positive effects on overall health by reducing, and even resolving, fatty liver disease, insulin resistance and type 2 diabetes. And the most significant thing is that lifestyle changes to include a healthy diet and some level of exercise (can be simply walking the neighborhood) are, if not free, dramatically cheaper than doctor visits, medications, and hospital stays, not to mention lost wages.