Friday, 15 January 2010

An apple a day...

Once upon a time, there were Crab Apples. They were extremely sour (except perhaps for the Chestnut Crabapple) and contained a lot of Pectin, a soluble fibre/fiber. Then, we clever humans selectively bred apple trees over a large number of years and voila! We have the modern-day apple. Note that this contains on average 10.4g of sugar/100g of apple and only 2.4g of fibre/100g of apple. The British Dental Association claims that the Pink Lady, Braeburn and Fuji contain so much sugar that they cause tooth decay.

Different types of fruit vary hugely in their sugar content. Some fruits (blueberries & cranberries) also contain mannose. Bananas also contain starch, which turns into sugars as the banana changes colour from green to yellow to black.

Don't eat/drink too much fructose, as that goes straight to your liver where it tops-up liver glycogen and, once your liver glycogen stores are full, overspills as triglycerides a.k.a. fats into your liver & blood.

For more on fructose, see Sugar: The Bitter Truth by Robert H. Lustig, M.D.

As glucose and fructose have very different effects on the body, this is a situation where "a calorie isn't a calorie".

6 comments:

Dr.A said...

Yes, I don't suppose that modern fruit is much like it used to be. I used to be a serious fruitaholic.. thinking it was good for me. But now I only occasionally eat a few raspberries or use one banana in 12 muffins...
and when I am in Italy and I can't be bothered to go down the mountain to the shops, I have to live off my seven fig trees!

Nigel Kinbrum BSc(Hons)Eng said...

You have seven fig trees in Italy? I bet they give you a good "run" for your money. Arf!

I thought that waxing lyrical about fruit would make a good intro' for Dr Lustig's presentation.

Dr.A said...

Amazingly they have no effect on me.. but I only eat them when I've run out of everything else...

Nigel Kinbrum BSc(Hons)Eng said...

Figs definitely have an effect on me.
Vive la difference!

Jin Hee said...

But I love fruit too much.

If the worry is about tooth decay, I'd rather brush my teeth (yes i know-after half an hour!).
But making my liver fat is a whole different issue.

Thanks for the info.

Nigel Kinbrum BSc(Hons)Eng said...

Hi Jin.

You love fruit? So eat fruit! Just don't try to live on the stuff as there's not enough protein & essential fatty acids in it.

My post allows you to find out how much of each type of sugar there is in each type of fruit so that you can select fruits with less sugar but which still taste good. Not all types of apple are crammed with sugar, so you can still eat apples.

As whole fruits contain some fibre, don't worry about your liver. It's refined fruits e.g. juices, smoothies etc that allow you to over-consume fructose.

Nige.