Help ...... need explanation of raw/cooked calorie labelling!

[philph]

Most food products in the UK have a nutrition label from the manufacturer, indicating number of calories and number of grams of certain nutrients.

As I'm trying to control my calorie intake with some precision, I usually use the numbers on these labels in my calculations, to see how much of everything is in a can, or 100 g, or whatever.

But some foods have no labelling at all, and in those cases I try to use the nutrition info from various web sites.

In some cases, though, I just can't make head nor tail of the numbers. Take "gunga peas", for instance. Having first of all discovered that these are called "pigeon peas" in the US, I looked up the nutrition info for this food, and found that it lists one lot of numbers for the "raw" beans and another lot for "cooked - boiled".

Just looking at the total calories, here's what it says:

cooked - 1 cup (168 g) = 203 calories
raw - 1 cup (205 g) = 703 calories

Now, as we don't have a measurement called "cups" in the UK, I divided the weights out to give the following per 100 g:

cooked - 100g = 121 calories
raw - 100g = 343 calories

Now, the manufacturer's label on my can of beans lists a net weight and a drained weight. The drained weight is 230g.

So - my questions are: if I take a can of these beans and drain them, leaving 230 g of beans, and then I heat them up ready to eat, what is the total number of calories that will be consumed?

Why does the raw bean have nearly 3 times as many calories as the equivalent weight of the cooked bean? Does it lose calories during the heating? Or what?

[CJohnson]

It really depends on how you actually do the heating. All heating methods deplete vegetables of nutrients. If you were to microwave the beans, then you would deplete a large portion of the nutrients and lower the calories. Steaming them, however, doesn't remove much at all. The equilibrium works something like this (from least loss to greatest):


Raw - Steamed - Baked - Microwaved - Boiled

[jsbrook]

From fitday: pigeon peas, cooked from can, fat not added, 100 grams = 110 calories. If you have diet software like fitday, you can look up pigeon peas raw, cooked, in cups, by ounces, by grams, or any other way that you can. Fitday is $29 I think. I find that it's worth the money. There are other programs that are very popular like DietPower. I think there's actually a recent thread on them.

[philph]

Originally Posted by jsbrook

From fitday: pigeon peas, cooked from can, fat not added, 100 grams = 110 calories. If you have diet software like fitday, you can look up pigeon peas raw, cooked, in cups, by ounces, by grams, or any other way that you can. Fitday is $29 I think. I find that it's worth the money. There are other programs that are very popular like DietPower. I think there's actually a recent thread on them.

Thanks for the suggestion, jsbrook. I think I'm going to buy the PC version, as it seems to list more food variations than the online version. I use the online system at fitday.com, and when I search for "pigeon peas" it lists only:

Pigeon peas (red gram), mature seeds, raw
Pigeon peas (red gram), mature seeds, cooked, boiled, with salt
Pigeon peas (red gram), mature seeds, cooked, boiled, without salt
Stewed pigeon peas, Puerto Rican style (Gandules guisados, Gandur, Gandules)

But regarding "cooked from can" - does that mean if I take a can and drain it, then cook 100g of the (raw) drained contents, then the cooked yield will be 110 calories? Or does it mean that if I weighed out 100g of the finished, cooked beans (which might be a different weight than they were raw, depending on whether they soak up water, etc), then we'll get 110 calories?

Originally Posted by cjohnson

Raw - Steamed - Baked - Microwaved - Boiled

Thanks - I knew there was some reduction in nutrients, but I had no idea that boiling could destroy nearly two thirds of the calories in the raw food. As I have been boiling most of my beans (and occasionally microwaving), this means I've completely miscalculated a lot of my calories for the last few weeks.

To make matters worse, on the foods I buy, the label never says which method of cooking is understood to yield the calories quoted. It also doesn't say whether the weights used to reference the calories are the weights of the raw food or the weight when cooked - which might be different

[philph]

However.........as my wife reminded me when I told her about this, when you cook beans, they absorb water and get heavier. Therefore, gram for gram, the cooked bean (which now has added water) has fewer calories.

Moreover, beans in a can come pre-cooked. When I warm them up prior to eating, this is a different situation from when I buy raw beans, soak them for 12 hours and then boil them for 45 minutes.

I'm guessing, then, that the drained weight of these beans corresponds with what fitday.com calls "Pigeon peas (red gram), mature seeds, cooked, boiled, with salt". Now, if only I knew what a "cup" is (which is the only available unit that fitday.com allows for pigeon peas), I'd be in business