Snacking and Fatty Liver Disease

Why eating more often during the day may harm your liver

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High-fat, high-sugar snacks can harm your liver. Brian Klutch / Stone / Getty Images

One of the most highly-debated aspects of weight control for adults of any age focuses on whether you should snack between meals to stave off hunger and eat less overall.  While healthy snacks that don't exceed your daily calorie needs might help tide you over until your next meal, there's now evidence that eating more often during the day contributes to weight gain, leads to more abdominal fat, and can lead to fatty liver disease too.

Eating frequency:  According to a small Dutch study published in the journal Hepatology in 2014, adults who ate more often during the day during a six-week period gained more dangerous belly fat, as well as an increase in intrahepatic triglycerides (IHTG), considered a marker of fatty liver disease. 

When the liver contains more than the usual 5-10% fat, it is more vulnerable to inflammation and scarring.  Non-alcoholic fatty liver disease (NAFLD) may have few symptoms but can eventually compromise the function of this crucial organ.  A small proportion of adults with a fatty liver will go on to develop non-alcoholic steatohepatitis or NASH, which can result in hardening of the liver (cirrhosis) and liver failure.

Studying snacking and the liver:  To determine the role of eating frequency - that is, eating either at three pre-set mealtimes, or eating between meals as well - 36 lean men were put on a balanced diet or a high-calorie diet (consuming 40% additional calories).

  The extra calories came in either a high fat/high sugar or a high-sugar beverage, consumed with a meal or within two or three hours of a meal. 

After six weeks the scientists, from the Academic Medical Centre in Amsterdam, measured triglyceride levels and abdominal fat in both the balanced-diet and high-calorie diet groups.

  The IHTG levels went up significantly (45-110%) in both the high-fat/high-sugar and the high-sugar subjects.  Surprisingly, IHTG levels did not increase among subjects who consumed the same high-calorie supplements with a meal. 

The researchers conclude that snacking on a high-calorie diet leads to both increased liver triglycerides and more abdominal fat even though eating the same excess calories only at mealtime did not have the same effect. 

How does snacking contribute to a fatty liver?  The researchers write that the exact mechanism is still a mystery, though they suggest that a constant stream of nourishment (via frequent meals and snacking) may be metabolized in the body differently than food eaten after even a brief period of fasting.  Further, too much sugar might affect liver triglycerides in a different way compared to too much of both sugar and fat, since the levels of IHTG increased significantly more in the high-sugar snacking subjects (110%) vs the high-fat/high-sugar men (45%).

 

Other recent research on shifting eating patterns such as intermittent fasting - during which various patterns of normal-calorie intake days are juggled throughout the week with low-calorie days (500 calories or so) - has shown metabolic changes shift depending on how often, as well as how much, food is eaten.  Intermittent fasting has been shown to lead to greater fat loss and less lean muscle loss, for example.

Would healthy snacks have the same effect?  The Dutch team did not test the health effects of snacking on fruits, vegetables and other foods rich in nutrients and longevity-boosting fiber. While these foods have been shown to lower your risk of disease and slow aging, they do not make up the bulk of snacks consumed by the average North American; in fact, according to these researchers, up to 27% of calories consumed by American children come from high-fat and high-sugar snack foods. 

Sources:

D.M. Cutler, E.I.Glaeser, and J.M. Shapiro. “Why Have Americans Become More Obese?” Journal of Economic Perspectives Volume 17, Number 3—Summer 2003. Pages 93–118.
http://faculty.chicagobooth.edu/jesse.shapiro/research/obesity.pdf

Karin E Koopman, Matthan WA Caan, Aart J Nederveen, Anouk Pels, Mariette T Ackermans, Eric Fliers, Susanne E la Fleur, and Mireille J Serlie. "Hypercaloric Diets With Increased Meal Frequency, But Not Meal Size, Increase Intrahepatic Triglycerides: a Randomized Controlled Trial." Hepatology doi: 10.1002/hep.27149

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