Washington, Feb 14 : A new study has revealed that eating too much of fast food and doing very little exercise can harm the liver.
The study was conducted on a group of slim and healthy people comprising of 12 men and 6 women, who took a "fast food challenge" for four weeks, and were compared against a group of the same age and sex, who ate a normal diet.
The group with the fast food diet limited their levels of physical activity to just 5000 steps daily and ate at least two fast food meals, from well-known outlets, daily.
The main purpose for the whole exercise was to double the calorific intake and increase the total body weight by between 10pct and 15pct so as to find out if it had any impact on their liver's health.
The study involved the taking of blood samples before the experiment began and then at regular intervals throughout the study period, to check on the condition of their liver enzyme and fat levels.
The damage that has been done to the liver is often identified by the symptomless increases in enzymes, of which alanine aminotransferase (ALT) is one.
ALT levels that are higher than normal are usually found in people who regularly drink large amounts of alcohol or who have been infected with the hepatitis C virus. But in some people, no explanation can be found for the cause.
Another factor, by which damage to the liver can be assessed, is by the fat that has accumulated there, a condition known as "fatty liver."
It was discovered at the end of the four weeks, that the people in the fast food group had put on an average weight of 6.5 kg. Five of them had their weight increased by 15pct and another had put on an extra 12 kg in just two weeks.
It took just one week for a sharp increase in ALT to occur with the fast food diet, and it more than quadrupled from an average of 22 U/l to of 97 U/l over the entire period.
The results showed that in 11 people ALT rose to the level that could have caused liver damage. The ALT increases were attributed to the weight gain and especially to the higher sugar and carbohydrate intake.
The study found also found that only one participant developed "fatty liver," while test results from the other participants showed a steep rise in fat content in their liver cells, which is associated with insulin resistance.
No such changes were seen among those who continued to eat their normal diet.
The study was published ahead of print in the journal Gut.