How do some things not have calories?

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Like, water has no calories. But plants do? And some random elements have like billions of calories but if you just pick up a rock and eat it you won’t get any energy.

In: Biology

4 Answers

Anonymous 0 Comments

Nutritional calories are measuring how much energy you get from food when you digest it. Digestion means taking bigger molecules and breaking them down into smaller molecules, releasing energy.

Your body can’t break down water into anything smaller. Water is a really happy, stable molecule. It’s not easy to break water down into the hydrogen and oxygen atoms that make it up.

You can digest plants, because plants have molecules in them like sugars and other carbohydrates, which your body can digest and get energy from.

When people talk about things like uranium having calories, they’re kind of joking. They’re talking about the energy that uranium could release in a nuclear reaction, and measuring it in calories. You can’t eat uranium. And if uranium was undergoing a nuclear reaction in your stomach, it wouldn’t nourish you. It would just kill you. And everyone around you.

Anonymous 0 Comments

There’s a 449 rule that everyone should know. It’s a rule of thumb and take with that grain of salt!

It states that on average, 1 gram of carbs or protein contain 4 calories and 1 gram of fat contains 9 calories. So to calculate the total calories for a food you’d sum: (grams of carbs x 4) + (grams of protein x 4) + (grams of fat x 9).

Look at your food now. Which of the above three do you expect in it? Water? None. Plants? Carbs and protein. That donut? Lot of sugar (equivalent of carbs) and fat. Potato fries? Lot of fat (that too saturated) and carbs

Anonymous 0 Comments

Easiest (and, incredibly, accurate from a chemistry perspective) is to ask yourself “can I burn it?” Not just char it, mind you, but set it on fire and get energy from burning it directly.

If burning it produces energy, it has calories. The bigger the fire, the more the calories.

Anonymous 0 Comments

Plants are carbs but we can’t digest them, our gut microbiome does. So we absorb minimal calories from these.

But it’s important to eat plants because the gut microbiome biome is responsible for 70% of our immune, mood and metabolism.

Some healthy fats like nuts are high in calories, but pass through the body partially undigested, meaning less calories absorbed. Fats also help metabolism = more calories used.

Proteins are hard work to break down (thermic effect), so although we’re consuming calories, we’re burning more as well.

Natural healthy carbs are packed with fibre and fruit. That’s why they’re lower in calories. Glucose spikes and absorption are reduced by fibre.

Also calories in / out is a gross simplification of how the body works. Calories mean nothing if you’re causing glucose spikes and releasing insulin, both storing fat and being unable to access fat stores to burn.