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19 Apr 2006

EtOH kJ content and beer
Hi Doc

I read in some other reply of yours that alcohol has 2 900 kJ/100 g! Calculating the kJ contribution of EtOH in a can of beer would be simple math, but what is the total kJ content of most SAB beers and do they differ a lot? And also, I read somewhere that beer has a GI value of 105! In my opinion according the GI definition that's impossible and is it really that high? Thanks

Answer 398 views

01 Jan 0001

Dear Ben
Well, 1g of alcohol does contain 29 kJ, but it depends how much alcohol there is in a drink like beer. According to the SA Food Tables, beers with an average alcohol content of 3,6% w/w contain 172 kJ per 100g. Now 3,6% w/w of alcohol = 3,6 g of alcohol per 100 g, which contributes 29 x 3.6 = 104,4 kJ. The remaining energy in the beer is derived from the carbohydrate it contains (e.g. about 4g per 100g). The energy contents of the beers can differ, with lite beers containing less energy per 100g. I don't have the GI value for beer in my copy of the SA GI Guide, but you may find it if you visit the GI Foundation Website at: . It is perfectly possible for a product that have a higher GI value than the standard 100 (which is usually white bread) as it depends on the type of effect it would have on insulin levels in the blood. A beverage that contain only high GI carbohydrate and alcohol could easily exceed the effect exerted by white bread.
Best regards
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