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  • Ever counted calories using nutritional labels?

  • But just how accurate are they anyway?

  • Hey, guys, Julia here for DNews.

  • Food labels are great.

  • They give you an estimate of how many calories are in any certain food.

  • But they have a teeny bit of a flaw.

  • They fail to take into account cooking.

  • So we end up with a system that likely overestimates the calories available in unprocessed foods and underestimates the calories in processed food.

  • The way we currently count calories is based on the Atwater System, which is at least a hundred years old.

  • The System standardized the idea of the amount of energy available in food, 9 calories in a gram of fat or 4 calories in every gram of protein.

  • But this measures the availability of energy in food, not the digestibility.

  • A calorie is a unit of energy.

  • It's technically the amount of energy needed to heat up a kilogram of water by 1 degree Celsius.

  • Our body burns calories in food through metabolizing the carbohydrates and proteins and whatnot into smaller molecules our body can use as energy.

  • Cooking food changes how many calories are digestible.

  • Take potatoes for example.

  • When raw, the sugar molecules in potatoes are too tightly packed for our digestive system to handle.

  • Cooking causes the starches in the potato to gelatinize.

  • That process allows us to access the sugars stored in the starch, so we get more calories out of the cooked potato.

  • On top of that, the type of cooking method might change the chemistry of food as well, whether it's boiled, baked, or microwaved.

  • On the other hand, digesting raw food takes work: A stick of celery might have 10 calories, but the chewing and digesting burns about half of them.

  • All that work means there are fewer calories for your body to absorb for energy.

  • But before you go nibbling on an all-carrot diet, consider this:

  • For our ancestors, cooking meant the difference between life and death.

  • The invention of a cooked meal might have changed everything.

  • Cooking food provided more energy and led to humans with bigger brains and bigger babies.

  • And people who consume an all-raw diet now might not be getting enough calories, even when eating food packed with nutrients.

  • Some women on an all-raw diet get irregular menstrual cycles—a sign of undernourishmentnot to mention the bacteria of your gut steal a few of the calories for themselves.

  • So the exact number of calories you're getting is affected by way too many factors for those labels to be truly accurate.

  • But while modifications to the Atwater system have improved it some over the years, there's still no real alternative.

  • So until nutrition scientists come up with a better calorie counting system, take food labels with a grain of salt.

  • See what I did there? Grain of salt? It's a... pun... ok.

  • Switching gears for a second, I wanted to let you know that tomorrow, Trace, Amy, and Ian are gonna be chatting with a real-live astronaut about what it's like to live and work in space.

  • And if you wanna hang out with us space nerds, be sure to RSVP using the link we've got in the description.

  • That's at 3 p.m. Eastern time, noon Pacific.

  • So, do you trust nutritional labels?

  • Do they need to be updated?

  • Leave your thoughts and comments below, and don't forget to subscribe for more DNews everyday.

Ever counted calories using nutritional labels?

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