My educated guesstimation would not include OG as a factor, rather the FG. Any sugar, fermentable or not will manifest itself as a dissolved sugar and cause an increase in OG. If it is fermented, it will become ethanol obviously and lower the FG and any unfermentable will remain as residual FG. So the higher the FG, the higher the amount of sugar that remains. Ethanol is listed at about 7 calories per gram, compared to 9 for fat and 4 each for carbohydrate and protein. A 355mL beer at app. 1.01 SG and 6% EtOH (meaning about 359 mg per 12 oz, or almost 480 g per pint times 6% w/v alcohol would put us at 28.8g grams of ethanol, or 28.8g*7cal/g = 202 calories per pint just for the alcohol plus the sugar, which would be minimal for a beer with such a low gravity). For a [maltier] beer with more residual sugar, we would have more of a caloric contribution, though not an appreciable amount more.
Can anyone confirm this or make a case against? Please advise.