10 calories for 1 calorie of food

In summary, the conversation discusses the ratio of energy input required to produce 1 calorie of food, taking into account the fact that food calories are actually kilo calories. The speakers also mention how certain foods may require more energy to produce, such as lettuce, compared to others like beans. There is also mention of the energy input from sunlight, fertilizer, and transportation in the production of food. The conversation concludes with a discussion on the efficiency of producing ethanol from corn.
  • #1
PhilKravitz
When people say it takes 10 calories of energy to produce 1 calorie of food are they taking into account the fact that food calories are actually kilo calories? Does it really take 10 kilo calories of energy to make one kilo calorie of food energy? Or do they mean 10 calories of energy to make 1 kilo calorie (1000 calories of food) of food energy?
 
Physics news on Phys.org
  • #2
I'm sure they have their units correct and it takes 10x as much energy to produce food. Some foods are probably ridiculous in this comparison. A piece of lettuce? How much food energy could that possibly store? Then think about all the energy it takes to harvest foods like that, process it, transport it to a store, etc.
 
  • #3
on the other extreme we have beans
 
  • #4
To my understanding it would be against the nature of entropy increase over time for 0.01 kcals being sufficient to produce 1kcal of food. Which, while not impossible is tremendously unlikely. Especially to such a huge magnitude.
 
  • #5
Does it take 10 calories from fuel to produce 1 calorie in the form of ethanol derived from corn?
 
  • #6
TheTechNoir said:
To my understanding it would be against the nature of entropy increase over time for 0.01 kcals being sufficient to produce 1kcal of food. Which, while not impossible is tremendously unlikely. Especially to such a huge magnitude.

There is energy input from sunlight on the growing plant. We are talking about energy in fertilizer and tractor use and truck distribution.

Yes if I grow beans in my back yard with no added fertilizer and pick them by hand and walk them to the kitchen yes we can have 1 kcal of food with 0.01 kcal of energy from sources other than the sun.
 
  • #7
Phrak said:
Does it take 10 calories from fuel to produce 1 calorie in the form of ethanol derived from corn?

You make a good point if it really did take 10 cal to make 1 cal ethanol would be a bigger looser than it already is.
 

1. What does "10 calories for 1 calorie of food" mean?

This phrase refers to the concept of energy density in food, which is the amount of calories per unit of weight or volume. In this case, it means that for every 1 calorie of food, there are 10 additional calories of energy that the body must use to digest and absorb the food.

2. How is the energy density of food determined?

The energy density of food is determined by calculating the number of calories per gram of the food. This can vary depending on the macronutrient composition of the food, with fats having the highest energy density at 9 calories per gram, followed by carbohydrates and proteins at 4 calories per gram.

3. Why is the concept of "10 calories for 1 calorie of food" important?

Understanding the energy density of food is important for maintaining a healthy diet and managing weight. Foods with a higher energy density, such as processed and high-fat foods, tend to be more calorie-dense and can lead to overconsumption and weight gain. Choosing lower energy-dense foods, such as fruits and vegetables, can help with weight management.

4. Is it possible to consume negative calories with this concept?

No, it is not possible to consume negative calories with this concept. While some foods, such as celery or grapefruit, have a very low energy density and may require more energy to digest than they provide, the body still receives some calories from these foods. Negative calorie foods do not exist.

5. Can the energy density of food change?

Yes, the energy density of food can change depending on how it is prepared. For example, cooking methods such as frying or adding sauces and oils can significantly increase the energy density of a food. On the other hand, steaming or boiling can decrease the energy density. Additionally, the addition of fiber, water, or air to a food can also lower its energy density.

Similar threads

  • General Math
Replies
1
Views
693
  • Introductory Physics Homework Help
Replies
1
Views
3K
  • Biology and Medical
Replies
9
Views
2K
Replies
18
Views
1K
Replies
16
Views
4K
  • Other Physics Topics
Replies
12
Views
3K
Replies
2
Views
1K
Replies
4
Views
7K
  • General Discussion
Replies
6
Views
879
  • Thermodynamics
Replies
2
Views
1K
Back
Top