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Sugar bad sugary fruit good, got that?

I talk a lot about the problems sugar causes for the body. If you had to pick one reason for why your kid's generation will die younger than yours and be sicker in old age than they should have been you could do worse than pick a soda.  We have a very curious relationship with sugary drinks.  We will happily drink a 16 ounce soda and easily serve it to our kids.  No parent or other apparently rational person will sit down and eat 10 teaspoons of sugar and yet that is a common amount in our soda.

This is a small diversion, but

did you ever wonder how to kill a rat with food?



OK, that was fun but what about the point of this piece. We are clear about our advice to cut sugar out of your diet if you are trying to deal with fatty liver or its more serious relatives of NASH and cirrhosis.  That is unambiguous advice and we explore the issue in considerable detail on the website. Here is a somewhat tongue in cheek explanation of the clinical trial we, as a society, have been running on ourselves for a couple of generations now.

I keep getting the question of why am I supposed to give up deserts but eat fruit.  We are creatures who like our pleasures and sweets are so appealing that we are drawn to overindulge but we are not good at weighing the relative value or risk of the things we eat. The common explanation is that there is something in fruit, since it is "natural" that is protective so we are encouraged to eat plenty of fruit.  The natural is good theme is appealing but it is really just a bit of biochemistry.  The question you might ask is how safe is this wonderful glass of orange juice?


We know that fructose overload is bad for the liver so what is it with fruit.  The answer is that it isn't the fruit exactly, it is the dose. That is the rate at which you present fructose to the system for management. For a long time we thought only the liver could handle fructose but it turns out that the small bowel has a limited ability to turn fructose into glucose and minimizes that problem.  The challenge is that the bowel has a limited capacity and it is a continuous process.  Whatever comes through must be handled or passed along to the next process so if fructose arrives at a modest steady rate the liver never sees it.  Dump a big slug at the bowel and it can't manage it so the fructose is dispatched to the liver which isn't ideal.

So fruit carries the sugar into the system more slowly than a soda, as an example, and the bowel manages it unless you hit it with a big dose.  So why the orange juice question.  We give that to our kids and feel good about it.  Fruit, right? But consider the delivery mechanism.  An 8 ounce glass of OJ is about 4 oranges.  Did you ever sit down and eat 4 oranges in 5 minutes?  That sudden pulse of fructose likely overwhelms the bowel capacity and even though it is a healthy drink it contributes to stress you are putting on the system.

When you are managing an at risk liver, dose is important.  Taking care not to create short term pulses that the organ can't manage is important so more frequent small meals is better and whole fruit rather than juice is something to consider.


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