How Diet Cheat Days May Harm Your Health


2017-01-25 11:58

Many diet plans these days include a cheat day - but this shouldn’t be a free pass to go overboard on fatty foods. Too many of these may negatively affect liver function.

We all need a day where we can be free of worry from “bad” foods – a holiday, a special occasion, or even just a day when we need to de-stress. On those days, we may tend to eat high fat foods – cheeseburger and fries or a cheesy pizza for example. It really is okay to enjoy these foods once in a while, but keep in mind that doing this too frequently can really wreak havoc on your liver.

Liver cells – called hepatocytes – are the key players in nutrient metabolism. For example, excess glucose (sugar) entering the blood after a meal is rapidly taken up by the liver and stored as glycogen. This energy storage is later used by the body as fuel between meals. If there is more than the body can store, it is converted into fatty acids and triglycerides and exported to adipose (fat) tissue.

Eating too much of any nutrient can overload the liver cells – an effect which appears to happen more rapidly than we thought. Researchers with the German Diabetes Center at Heinrich Heine University have found that saturated fat especially can alter the work load of the liver and over time this stress can lead to more serious conditions such as fatty liver disease.

In a small study, 14 healthy young men consumed levels of saturated fat equivalent to that of an eight-slice pepperoni pizza or a cheeseburger with large fries. They found that the “fat-loading” caused the liver to produce 70% more glucose. This added workload stresses the liver cells. The liver cells also appeared more prone to store fat rather than glucose, which increases the risk of fatty liver.

"The effects mimic the abnormalities seen in people with severe metabolic disease," said study co-author Dr. Michael Roden.

"Saturated fats such as in butter, fatty cheeses and coconut oil are thus the worst thing to eat from the liver perspective," said Yki-Jarvinen, co-author of a commentary accompanying the new study.

Non-alcoholic fatty liver disease is increasing in the US. It is thought to affect as much as 25% of the population. This condition causes the liver to swell and can eventually develop into cirrhosis, a scarring of the liver.

It is possible to improve liver health says Yki-Jarvinen. "If you change your diet to a more healthy one containing healthy fats, such as found in olive oil, your liver fat decreases in a few days," she said.

Journal Reference:
Michael Roden et al. Acute dietary fat intake initiates alterations in energy metabolism and insulin resistance. J Clin Invest. 2017. doi:10.1172/JCI89444

Additional Resource:
American Liver Foundation

Photo Credit:
By SunOfErat (Own work) via Wikimedia Commons