I was looking at a Hershey’s Milk Chocolate Bar ™, and saw that it has 230 calories. I know that a dietary calorie is equivalent to 1000 chemistry calories, i.e. one dietary calorie will raise the temperature of a liter of water 1 degree Celcius. And I know that people who put the calorie information on the label burn the food and/or calculate the content based on the combination of fats/carbs/protiens in the food.
So my question is, do the calories printed reflect any efficiency factor adjustment? If so, what is it? If not, what can I “write off” due to my body’s ineffiency? Can I say that my body is only 60% efficient and only write down 60% of the printed calories?
I’m not sure if the calories printed on things reflect any factor adjustment. I do know that it depends on the macronutrient that you are eating on how efficient it is burned. I don’t have a cite offhand, but from my memory of reading nutrtion articles, how many calories you need is already factored into that. So no, you don’t need to eat more.
From my experience, the BMR calculators I have used are very accurate, yet take no factors into energy lost in the process of digesting or using said calories. I live right on the line most of the time. I am currently maintaining, and eat about 2300 calories. I gain no weight, nor lose any. Haven’t for 3 months. (haven’t gotten weaker or lost muscle mass either) However, when I add 250 calories every day for a week, I gain a pound. Since there are 3500 calories in a pound of fat, I don’t see where there can be much energy lost.
I will try to find some sites later, but for now I need to go to classes, I am already going to be late, lol.
This column explains how calories are measured. The efficiency of the body doesn’t enter into it - the number of Calories printed on the package describes how much energy is contained in the food.
I think you are correct in that some types of food are absorbed less efficiently than others and have lower “effective Calories.” Foods that contain lots of fiber, for instance. But I think most energy in your Hershey’s Milk Chocolate Bar ™ is in the form of sugars and fats, and are absorbed very efficiently. And once absorbed into the bloodstream, it’ll get used one way or another (i.e. either for mechanical energy or simply as heat).
Incidentally, athletes are about 25% efficient at turning sugar into mechanical energy according to a book I was just reading (Human Powered Machines by Gordon Wilson et al.) The rest is turned into waste heat.
scr4 - So you are using the column to indicat that there may be more energy in protien, carbs, and fat than 4, 4, and 9 calories, but those are the amounts the body can extract?
If that is true, then the efficiency factor has already been applied.
Thanks!
Swoop - Thanks for the bump
Epimetheus - Couple of things. If you eat 250 every day for a week, you would only gain 1/2 a pound, 7 * 250 = 1750, probably just a typo.
As for the BMR calculators, they don’t seem to be working for me. My data shows that if I consume 9.75 cal/lb/day, that I lose about 1.4 lbs/week. Using the 3500 cal/lb weight loss would put me at an actual BMR of 12.6 cal/lb/day, which seems high based on my lifestyle. I believe that the 3500 cal/lb number is true in some respects, but doesn’t work very well in calculating BMR. If I use a different number for weight loss, i.e. each pound of lost weight is around 2750 calories worth of fat, and the other weight is lossed lymph, plasma, or blood that is no longer needed due to the fat loss, then my BMR is around 12.0 cal/lb/day, which sounds more realistic. I was hoping that there was an “efficiency factor” that would explain the ‘caloried gap’.
I could go on and on, but it looks like the ‘gap’ explanation lies elsewhere.