Feb. 14, 2008

Fatty Fast Food, Idleness May Vex Liver

Enzyme Levels Quickly Rise In Subjects Who Supersize Theselves From Diet, Lack of Exercise

  •  (CBS/AP/iStockphoto)

(WebMD)  Consistently overdoing it at the fast-food counter and leading an idle life may not bode well for the liver, not to mention the waist size.

So say Swedish researchers who studied 18 lean, healthy students - mainly medical students - who agreed to supersize themselves for science's sake.

The students were asked to gain 5% to 15% of their body weight in a month by eating at least two daily meals at fast-food restaurants and adopting a sedentary lifestyle. Their fast-food diet featured hamburgers and other foods high in saturated animal fat. The researchers reimbursed the cost of those meals.

Before-and-after measurements show a ballooning of the students' weight, waist, fat, and liver enzymes.

On average, the students gained 14 pounds, added 2.6 inches to their waistline, and padded their body fat percentage by 3.7% during the study.

Blood samples provided by the students throughout the study show a spike in levels of the liver enzyme alanine aminotransferase (ALT). ALT levels rose quickly - typically within a week - after the students started the fast-food diet.

High ALT levels can be a sign of liver damage. But other tests show that most of the students didn't develop fatty liver disease during the month-long study.

The researchers - who included Fredrik Nystrom, MD, PhD, of Sweden's University Hospital of Linkoping - aren't focused on the occasional burger, but on a habitual pattern of being idle and overeating fattening foods from any source.

The study, published in the advance online edition of Gut, doesn't show which was more damaging - bingeing on fatty food or being sedentary. And it doesn't mean that all fast-food meals are bad choices. It's possible to make healthier choices at many fast-food chains.


By Miranda Hitti
Reviewed by Louise Chang
© 2008 WebMD, Inc. All rights reserved.
Add a Comment
by puzzler125 February 14, 2008 8:41 PM EST
This is an unhealthy amount of weight to gain in one month and a dangerous study!
Reply to this comment
by richieaok February 14, 2008 7:07 PM EST
The reasons found for liver enzyme spikes found in the study were different than reported here. Quote un Quote from one of the researchers Fredrik Nystrom :

"It was not the fat in the hamburgers, it was rather the sugar in the coke," Nystrom said.

"We found that healthy HDL cholesterol actually increased over the four-week period -- this was very counter-intuitive," Nystrom said.

It was found that excessive carbohydrates from the massive amounts of soda, fries, hamburger buns, etc.. they consumed was the main factor in spiking the liver enzymes, not saturated animal fat!

The increased intake of saturated fat was found to actually increase the levels of HDL cholesterol, commonly known as good cholesterol. HDL cholesterol is thought to help clean out the arteries.

What is really supported by this study: Don''t overeat (they attempted to double their calorie intake). Especially don''t over consume carbohydrates (sugars, starches, etc...). Saturated fats have some benefits (not that you should over consume them, obviously). Make sure you aren''t sedentary (get some exercise).

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