The way a food is prepared can change the percentage of calories and nutrients absorbed from it. For example:
Cooking. Cooking breaks down food and makes it more absorbable–both the contained calories and some of the nutrients. This is a bummer for those of us who hoped baked apples and all-fruit jam were as weight-friendly as raw fruit.
Grinding. You absorb more calories from flour than from whole grains and more from peanut butter (or any nut butter) than from eating the whole nut. One study found a 25% difference between nuts and nut butters. Ground meat also offers more absorbable calories than steak.
Juicing. The fiber in fruits and veggies can prevent some calories from getting absorbed when eaten whole. Removing the fiber makes it easier (and faster) to absorb everything else. This is why many experts are fine with vegetable juices–which barely contain any sugar or calories–but warn against consuming too many fruit juices. (Carrots, beets and a few other veggies do have enough sugar that experts suggest eating those more than juicing them.)
Blending. Fruit smoothies generally give you more absorbed calories than chewing your own fresh fruit. Ditto for most other things you might put in the blender, such as beans (for hummus) or blended soups or mashed potatoes.
Heating (or re-heating). Even if a food is already cooked, like a day-old leftover baked potato, there appears to be a difference between eating it cold versus reheated.
In some ways, this feels like the same old “processed foods make you gain weight” information, although it reminds us that just heating or blending healthy whole foods counts as processing them. It suggests that for folks who want to lose weight, it really does make a difference to exchange nut butter for raw nuts, cereal or bread for whole grains like brown rice, fruit roll-ups for fresh fruit, and so on.
Many clients ask how to count absorbed calories versus eaten ones, and I’m stumped on that one. Let me know if you have any ideas.
Have a good week!