Counting Calories for Cooked vs. Raw Foods
Simply put, foods change in volume/weight during cooking. Certain foods, like meat or fish, shrink. Others, like pasta or oatmeal, expand. But what’s important to remember, is that the difference between cooked vs. raw is mainly due to changes in water content. Meat shrinks because moisture is lost. Oatmeal expands because water is absorbed. Water has no calories, so the absolute calories and macronutrient content of the cooked food doesn’t change to a significant extent…just the calories and macronutrients per unit volume.
Whether you use “cooked” vs. “raw” calories really comes down to the number of people being served. If, for example, you’re making a single serving of oatmeal, the “raw” calories will do nicely…what goes into the pot is also what comes out. Yes, it’s expanded from – say – 1/2 cup to 1 cup – but it doesn’t matter, since you’re eating the whole thing. Ditto for a boneless, skinless chicken breast…the 5 oz. breast you put in the pan may shrink to 3.5 oz. after its cooked, but it it’s no big deal…the total amount of protein – the primary source of calories – hasn’t changed. A few fat calories may have been lost during cooking, but since the chicken was low in fat to begin with, the “error” is trivial.
Of course, you could also use the “cooked” calories for the above examples too…if you decide to measure your food after it’s cooked vs. before. Doesn’t matter, really, as long as you realize it’s not necessary to measure things TWICE (i.e., before AND after cooking). Dieting can be difficult enough, without adding unnecessary work.
On the flip side, if you’re cooking a pot of rice to serve for a family dinner, it’s simpler to measure your serving AFTER cooking, and use the “cooked” calories. Ditto if you’re carving a serving of meat from a larger roast (like pot roast or a turkey breast), or a portion from a recipe (like chili).
It’s not hard to find comprehensive calorie and nutrition information for both cooked and raw foods: my two favorite online sources are calorieking.com and nutritiondata.com.
December 2, 2011
from Physics, energy (calories) can neither be created or destroyed. So unless there is a chemical change that gives off heat in the cooking process, all the calories you put into the pot are still there. I read once, and it sounds logical, that the reason cooked foods can be more fattening is that cooking breaks down the food tissues and therefor your digestive system can utilize it more efficiently. Apparently this was a factor in mans evolution. When he learned to eat cooked food, his development accelerated.
February 16, 2012
But does not the nutrition content changes, how to you account for that?
February 16, 2012
Yes, some nutritional changes occur with cooking, although determining how much isn’t quite so straightforward! A lot depends on how you do your cooking. For example, you’ll lose more nutrients boiling broccoli in a pot of water than you will lightly steaming it.
NutritionData.com provides detailed values for the nutrients in foods that have been cooked/processed in different ways. Check it out.
March 1, 2012
I’m sorry, but that answer is just bull. It all sounds so reasoned. So, here’s a more specific question; 8 oz of 95 percent lean ground beef has 486 calories, or 60.75 calories per oz. By my measurement, after cooking that 8 oz of meat now weighs 6.3 oz. So if I multiply 6.3 oz times 60.75 cals, my calorie count is now 382.73 calories.
I understand that the nutritional values have not changed, other than changed caused by heat. But your calorie premise does not hold up under even the most basic scrutiny.
In your example above, with the chicken, you are simply saying that the raw chicken weight is being used to measure.
March 1, 2012
Wrong. Since you’re using very lean meat in your example, we can assume little-to-no fat rendering has occurred… most of the change in weight is due to loss of water (which has no calories). An ounce by weight of raw meat has more “water weight” than an ounce by weight of cooked meat, so the calorie counts per ounce are not the same between raw and cooked.