How Fattening is Fruit?
Have you ever been mid-sip of a delicious fruit smoothie when suddenly somebody warns you that it's very high in sugar and fattening for you? This happened to me recently. I finished the smoothie regardless, but noticed that it triggered some fear within me.
There has been a lot of media-hype around the restriction of sugar and carbohydrates in our diet recently. In fact, there are many medical professionals and diets out at the moment promoting the restriction of fruit because of its high sugar content.
Knowing how full of vitamins and antioxidants fruit is, I decided to take a scientific look at the sugar in fruit and its affect on our bodies. Is it worth restricting such nutritious food from our diet to prevent weight gain? This is what I found...
An introduction to fructose
Just to make sure everyone is on the same page, let's first take a look at what type of sugar is in fruit.
The sugar found in fruit is known as fructose. It is slightly different in structure to glucose (the sugar used by body cells to produce energy), but our body simply converts it into glucose and uses it in a similar way.
High fructose corn syrup
High fructose corn syrup (HFCS) is one of the main sweeteners used in processed, commercially-produced foods. As the name suggests, it has a syrupy consistency and is made from corn.
HFCS is generally favoured by manufacturing companies due to it being more cost-effective, sweeter and easier to handle than granulated sugar.
HFCS has been linked to a number of serious health problems. These include:
Liver damage.
Type 2 diabetes.
Obesity.
So HFCS seems to be the culprit for all the hype around fructose being bad for our health, but does fructose cause the same problems when eaten naturally in fruit?
How does fruit affect blood sugar levels?
The Finland Study
There was a study performed in Finland in 2012 on the effect of berries on blood sugar, insulin and free fatty acid levels.
The participants were first fed a reference meal of 35g of granulated sugar dissolved in water. Their blood sugar levels were monitored every 15 minutes for two hours.
On a different day, they were fed the same sugar water, but together with berry puree. Then on another day, this was repeated again with berry nectar (fibre removed).
The results found that:
When the sugar water was consumed by itself, the blood sugar levels of the subjects spiked very high, then dropped very low. Low blood sugar levels led to the release of free fatty acids into the blood, as if the body was in starvation.
When berry puree was eaten with the sugar water, the subjects blood sugar levels peaked less and dropped less afterwards, remaining more constant. As a result, less free fatty acids were released.
When berry nectar was eaten with the sugar water, it had a similar effect to the berry puree (just slightly less).
What does this mean?
It seems that when fruit is eaten together with another carbohydrate, even though the overall sugar of the meal may be more, the blood sugar levels don't go up as much and remain more constant afterwards.
What could be causing this? The two most likely contributors are:
Soluble fibre, which slows down stomach emptying.
Polyphenols (antioxidants), which have been directly linked to decreased blood sugar levels.
Is this the only study showing these results?
No, it isn't. There have been several other studies showing that while fructose in commercial foods causes negative health problems, fructose in fruit does not.
People on low fructose diets have actually been found to lose less weight than people who were eating a moderate amount of fructose from fruit.
Contrary to popular belief, fruit may actually aid weight loss, not prevent it.
Conclusion
If you want to cut down on sugar, rather focus on eating less foods that contain high fructose corn syrup and refined sugar.
It is much healthier to be getting most of your sugar from fruit, with the most benefit coming from fresh, whole fruits.
So ultimately, if you're going to eat waffles, make sure you have berries with them. :)
I hope you enjoyed this post and found it informative. Please share it with your friends and let me know which topic you would like next!
References:
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