Does Exercise Improve Fatty Liver Disease?

Nonalcoholic fatty liver disease is a potential consequence of carrying excess body weight, and is essentially caused by extra fat being stored in the liver. It is the third most common cause of liver cirrhosis, and affects up to 30% of the world’s population. 

Weight loss has been clearly established as the first line treatment for NAFLD, and we know that most successful weight loss strategies focus most attention on reducing calorie intake, with exercise playing only a minor part.  However, we know that exercise can have many cardiometabolic benefits even if a person doesn’t lose weight because of it, so it would be interesting to know if exercise itself could improve NAFLD.

A study was recently published in JAMA Internal Medicine which addresses this question.  In the study, 220 participants with NAFLD were randomly assigned to moderate exercise (brisk walking for 30 mins, 5 days per week) for a year, vigorous exercise for 6 months followed by moderate exercise for 6 months, or no additional exercise for a year.

They found that moderate and vigorous exercise were equally effective to reduce fat content in the liver, and that most (but not all) of the effect was mediated by weight loss. 

So, while actual reduction in weight remains the key factor in improving fatty liver, exercise may play some role even if the exercise itself doesn’t shed a whole bunch of pounds.  And it is good news that moderate activity is just as good as intense activity, as moderate exercise regimens like walking are more likely to be adhered to in the long run.

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2016

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(In)Accuracy of Your Wrist Technology for Estimating Calorie Burn

There are many different kinds of wrist technology out there - Garmin, FitBit, and Jawbone UP just to name a few.   In response to concerns that these devices may not be accurate to measure energy burn, researchers have now conducted a study to test how accurate they are.


The study, published in JAMA Internal Medicine, examined several brands of wearable energy tracking technology, and compared them to gold standard research methods of measuring energy burn, including both a standardized day (indirect calorimetry using metabolic chamber) and fifteen free living days (doubly labeled water method).  Brands studied included the Garmin VivoFit, Jawbone UP24, and FitBit Flex.

They found that these wearable devices were overall quite inaccurate, with inaccuracies ranging as high as 590 calories per day. !  Most of the inaccuracies were underestimates of caloric needs, while some overestimated needs.

So does this mean that these devices are totally useless?  No.  They can be great motivation for keeping track of daily activity and steps taken per day (pedometer) - though there are inaccuracies here as well.  But I do see a lot of people with weight struggles feeling frustrated that they seem to be burning way more calories (according to their device) than the food they are eating, yet they are not losing weight.   Overall, the biggest benefit of these devices is probably motivation to move, and keeping us engaged in mindful eating (ie we think more about what we are eating if we are keeping track of it).

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2016

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