The Nutritionist: Coke vs. Diet Coke

Cold Drink - Jonathan King

I have to admit, I used to be a Diet Coke addict before studying nutrition. Funnily never Coke, always Diet Coke, and always out of a can, never a bottle. Either version, though, is filled with chemicals. But which one is 'better'?

Both soft drinks contain carbonated water, caffeine, colour (caramel 150d) and flavouring. Not great, but it kind of makes sense. The difference between the two soft drinks is the amount of sugar in a normal Coke and the artificial sweetener, aspartame, in a Diet Coke. A can of Coke contains 10 teaspoons of sugar, which is - are you ready? - 100% of your recommended daily intake. This amount of sugar causes your blood sugar to spike, and your liver responds to the resulting insulin burst by turning massive amounts of sugar into fat.

That’s not good news. So of course you think you’ll choose the diet version, which has less than 1kcal and is sweetened with aspartame, also known as NutraSweet.

Even though it was approved by the Food and Drug Administration (FDA) more than 20 years ago, and with several studies showing it is safe, I disagree. There are now more than 90 different side effects associated with aspartame consumption, including brain tumors, birth defects, diabetes, emotional disorders and epilepsy/seizures. Other studies show that aspartame consumption can actually increase weight gain. One reason for this is its phenylalanine and aspartic acid content, which is known to rapidly stimulate the release of insulin and leptin, two hormones that are intricately involved with satiety and fat storage. To simplify, if your body is exposed to too much leptin, it will become resistant to it, and you’ll remain hungry, crave sweets and store fat.

How's that for ironic?

Now let’s have a look at what the caffeine does to your body. The caffeine absorption will be complete after about 40 minutes, causing your pupils to dilate, your blood pressure to rise, your heart to beat irregularly, and your liver to dump more sugar into your bloodstream. Now your body increases dopamine production, which stimulates the pleasure centres of your brain (a physical identical response to that of heroine by the way).

And to finish this off, you’ll have a massive sugar crash an hour after having had your soft drink fix.

I'll leave the decision up to you as to what’s better. And if you can’t decide, think about this: another active ingredient in Coke and Diet Coke is phosphoric acid. The pH is 2.6 for Coke and 3.4 for Diet Coke. The pH in our mouth is normally about 6.2 to 7. At a pH of 5.5 or lower, the acid begins to dissolve the hard enamel of our teeth.

And everyone knows what happens to a T-bone steak when you put it in (Diet) Coke, right?