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Does caloric value in food change with cooking?

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I've noticed when searching for things like eggs and chicken, even veggies like tomatoes or spinach, the caloric value is different based on how its cooked.

Why is this? I include what I use to cook these things with (for example if I'm making an omelet, I log in a tablespoon of margarine or olive oil or whatever I use to fry the omelet), is that right?

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Probably because the weight of the food changes as water evaporates during cooking (so 4 oz of chicken raw is different from 4 oz of cooked chicken), or it assumes that you cooked it in oil or added salt, etc.

I just log everything raw (with raw weights/quantities) so that nothing is assumed.

I think that depends on whether the cooked item is more or less calories compared to the raw item.

If the cooked item is listed with a higher caloric content, then I suggest that amethystgirl is correct and that a constant weight of cooked material has a higher density and has more calories associated with it.

If the cooked item is listed with a lower calorie content, then there is an interesting explanation. The whole concept of cooking comes down to chemistry. When you apply sufficient heat to a food item, then you cause chemical reactions to occur. So what does that mean for calorie content? It essentially means that when you cook food, you are literally burning calories that are contained within the food itself.

This is actually where the underlying science of calorimetry comes from. The measured value of Calories within a food item is a measurement of the energy contained within the chemicals within the food. In order to measure the amount of energy within something (usually in calories or joules), a scientist will place the item into a calorimeter and burn it. After accounting for the amount of heat applied to the system to light the item, the additional heat given off from burning the item is the energy within the chemicals themselves (the calorie content of the food).

Sorry if that was a bit too complicated than what you were expecting. I can try to explain better if I didn't make it clear. The basic take-home point is that when you cook anything, it loses Calories, although it may not be much.

ETA: oh yeah, and different ways of cooking apply different environments to the food, leading to different chemical reactions.

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Hello Simwaves1.  As an example: 100g of a certain coconut milk reports 200 cal.  If I were to chug 100g straight from the can I am certain I would reap all 200 of the calories.  However, If I fire up my wok and use the coconut milk in place of oil, after adding the vegetables and reducing  the "milk" to a non-liquid sauce, have I not effectivly "burned" a large percentage of the calories of the coconut milk much in the same way, (yet more extremely), than a body burns calories? And if I am correct in my supposition, what estimate would I use to accertain the correct caloric measure?

This info is very important to me.  I have just been diagnosed with onset diabetes and I am on a 90 day program to reverse it, (if possible). I have reverted to vegan diet and goodies like coconut milk add excitement to my cuisine selection.  But I'm willing to cut items like it out if I can't reduce their calories.  The example above is an actual event and I pondered the query as I stir-fried my veggies and concluded that there could not be many calories left from the coconut as there was no trace of the milk yet all the flavor was retained in the vegetables. Bor


Hi Bor. I'm sorry to say that I can't help you there. The amount of calories that you burn off by cooking your coconut milk really depends on how much you cook it. The longer you cook the milk, the more calories you are burning off. The only real way to get a good estimate would be to cook your meal in a calorimeter and measure directly the amount of calories that were burnt. That likely isn't a realistic option for you.

Since you are fighting off diabetes, it would probably be more effective and more conservative if you just use the uncooked calories in your log. There are lots of resources for diabetics in diet training. Have you been hooked into a diabetes education course yet?

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