Simple thinking: Eating fat causes fatty liver. But human biology is not that simple.
In a recent study of eating fast foods it was noted that there was increased obesity and fatty liver disease. Fatty liver disease can lead to liver cirrhosis, and death, or the need for a liver transplant. But it is the obesity, and more the carbohydrates from the obesity that lead to fatty liver disease.
When the media takes comments out of context this leads to misinformation; in this case when CBS quoted Dr. Ordon from “The Doctors” :
“The Doctors” revealed study findings that found regular consumption of fast food items like fried chicken and onion rings are particularly bad for your liver, and these fried foods have many surprising complications and dangers for the people that consume them.
“The amount of fat and saturated fats creates a condition called fatty liver,” said Ordon.
What’s interesting about the new information is that even after just a month of consistently eating fatty foods from fast food restaurants, there are significant changes in your liver. The fried foods do not just impact your cholesterol and waist line.
Ordon describes the changes in the liver enzymes as being surprisingly similar to the damage that is seen by hepatitis, which can ultimately lead to liver failure.
Reading this leads to the erroneous conclusion that eating fatty foods leads to fatty liver. With few exceptions, fatty liver disease starts with obesity. Some people have the tendency to deposit excess weight in their liver , which can lead to cirrhosis and death.
Fatty liver disease has less to do with dietary fat, and a lot to do with how the liver processes carbohydrates. How human beings process macronutrients, fats, carbohydrates, proteins and alcohol is quite complex, and “The Doctors” know this.
Here is the evidence:
When giving patients high glucose in their intra-venous fluids, surgeons discovered that their patient’s liver enzymes started to rise, from fatty liver disease. Ultimately, when surgeons then added lipids to the intra-venous nutrition, the liver enzymes of their patients stopped rising. It was discovered that to PREVENT fatty liver disease, there must be a BALANCE, and now lipids are routinely added to the intra-venous solution. High glucose alone gave fatty liver disease.
We have written about fructose, as one of the bad actors in carbohydrates (see High Fructose Corn Syrup: Health Risks). It is difficult to isolate fructose consumption in humans and seeing what fructose effects without relating it to consumption of excess calories. In a short (2 wk) dietary intervention study in fatty liver subjects, Browning (reference below) showed that carbohydrate restriction (< 20 g/d) was significantly more effective in reducing fatty liver content than just restricting calories to 1200-1500 kca Both diet interventions reduced body weight by the same amount (by about 4.3%). In a randomized intervention study comparing the consumption of sucrose-sweetened beverages (1 L/d for 6 mo) with other isocaloric beverages in obese subjects, Maersk (reference below) demonstrated that sucrose (half glucose and half fructose ) significantly increased fatty deposition, not only in liver, but also in skeletal muscle and in the belly.
MONITORING FATTY LIVER DISEASE
In some of my weight loss surgery patients we monitor their liver fat by checking with ultrasound. The ultrasound gives us a non-invasive way of seeing if their liver has more fat in it. If they have been avoiding “junk” foods, and loose weight we can see a decrease in the liver fat over time. If, on the other hand, they have gained weight, and we see that there is an increase in liver fat, when we check their diet journals it is often that their consumption of fructose has increased (usually from soda, juices, or other processed foods that have high fructose corn syrup).
Browning JD, Baker JA, Rogers T, Davis J, Satapati S, Burgess SC. Short-term weight loss and hepatic triglyceride reduction: evidence of a metabolic advantage with dietary carbohydrate restriction. Am J Clin Nutr. 2011;93:1048–1052. [PMC free article] [PubMed]
Maersk M, Belza A, Stødkilde-Jørgensen H, Ringgaard S, Chabanova E, Thomsen H, Pedersen SB, Astrup A, Richelsen B. Sucrose-sweetened beverages increase fat storage in the liver, muscle, and visceral fat depot: a 6-mo randomized intervention study. Am J Clin Nutr. 2012;95:283–289. [PubMed]