Negative Calorie Foods: Not

Rick bet me a dollar, saying that apples are a “negative calorie food”. IE: it takes more calories for your body to digest apples than the number of calories you get from them.

I was dubious to say the least. So I took the bet.

On about 7-14-09 I called the University of California at Davis at 530-754-9708. I spoke with a woman named Judy. She referred me to Dr Scott Johnson.

I called Dr Scott Johnson, Extension Pomologist at Department of Plant Sciences, UC Davis. He didn’t know the answer but said I should try 3 folks at the Department of Food Science and Technology at UC Davis:

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* Dianne Barrett, Specialist in Cooperative Extension, UC Davis School of Food Science and Technology (left message 7-14-09 4pm) no response.

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* Christine Bruhn, Specialist in the Cooperative Extension, UC Davis School of Food Science and Technology  (left message 7-17-09 12pm)

I spoke with Doctor Christine Bruhn she says that some of the nutritional values of foods in the USDA nutrition lists are determined in part by having people eat the food and then they measure all of the outputs (breathing, pooping, peeing, etc) to see how the body digested it. So the USDA nutrition info is pretty correct. If it says that celery has 6 calories per stalk, that accounts for the calories it takes to digest it… IE: Celery is a positive calorie food. Raw unpeeled apples really do give you 81 calories (page 28 of the USDA Nutritive Value of Foods book, or search for foods here)

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* Adel Kader, Professor of Postharvest Physiology UC Davis (spoke to him 7-17-09) said that there is no such thing as a negative calorie food… and that he didn’t know of any studies suggesting otherwise. I asked about how fiber might take more energy for the body to attempt to digest. He said, “Fiber facilitates thing moving quickly, so it might even end up taking less calories”.

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Next week I’m going to call my favorite science talk show, Doctor Karl and ask! I’ve always wanted an excuse to call him. He’s on 11am Thursday… errrr. That’s 6pm Wednesday PST, the show is in Australia :-)

In the mean time, I’ve asked Rick to get that dollar ready for me.

3 Comments

  1. Alexis says:

    I still hold true some form of this theory for ice cream; it must take a lot calories to process the icy delight (namely, heating it up to body temp)! Ask me sometime about my theory of how ice cream “melts around”.

  2. lee says:

    Oh yes, the incredible food science team of Ben Cohen and Jerry Greenfield have made innumerable advances in additive flavor enthalpy of fusion combinations.

  3. muffin says:

    i have heard there is a myth about spinach being super high in iron but that it came form a por shlub lab worker who misplaced a decimal point once…

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