Calorie Accuracy

albayin

I have been wondering about this for quite some time...

As we see quite a few posts daily asking why they (we) are not losing even when we track/log religiously...the questions that came to my head are

1. How do we know the number we find on this site/any other site is accurate? say does a 120 gram banana really have 125 calories?

2. Each individul is different. So if I eat 300 calorie worth of chicken breast, would it be broken down and converted to 300 calories? or less for some folks?

There are so many successful stories using the caloric deficit method. I don't doubt the science behind it but can't help but thinking does the science treat everybody equal, medical condition excluded of course...

I am honestly curious about this. Thoughts?

Mike13815

The nutrition facts on the site are pulled from many different sources. They're fairly accurate, matching ~5% to what I used to log before mfp manually, although I'm very precise in my matching and measurement while the average person isn't.

Calories aren't measured according to what the body is expected to utilize. They're measured through combustion, giving us an accurate reading (upon peer review) the maximum possible calories of a food.

So it's a maximum number, and nobody is going to absorb more than 300 calories from a 300 calorie food product, although they may absorb considerably less.

The biggest factor in losing weight when calorie intake is taken out of the equation is metabolism. Some people will burn considerably less calories for the same activities as others. The least efficient metabolisms are people you see eating burgers every day and not gaining weight. The most efficient ones are usually us, the ones on this site, struggling to lose weight.

Regardless of metabolism, a pound of fat is ~3500 calories. Eating 500 calories below your daily usage will burn one pound a week... you just need to find what your daily usage is.

bridgie101

I have been wondering about this for quite some time...

As we see quite a few posts daily asking why they (we) are not losing even when we track/log religiously...the questions that came to my head are

1. How do we know the number we find on this site/any other site is accurate? say does a 120 gram banana really have 125 calories?

2. Each individul is different. So if I eat 300 calorie worth of chicken breast, would it be broken down and converted to 300 calories? or less for some folks?

There are so many successful stories using the caloric deficit method. I don't doubt the science behind it but can't help but thinking does the science treat everybody equal, medical condition excluded of course...

I am honestly curious about this. Thoughts?

The laws of physics rule the situation. A calorie is the amount of energy required to heat one cubic centimetre of water one degree from something (can't remember the specific temps) like 3*c to 4*c.

which is to say, it's a unit of energy.

If you have done any physics in high school, you might remember the first law of thermodynamics: that energy is neither created nor lost, but can only be transferred, transformed... transmuted. It can neither increase in size nor shrink in size. what were the kinds of energy? heat energy, kinetic energy, potential kinetic energy, gravitational energy, stuff like that.

so anyway, that banana is capable, if dried and set on fire, of heating 120 cc's of water one degree from 3 to 4*c (or whatever that number is above zero.) That's all it can heat. It can't heat more. That 120 calories is capable of moving an object of x mass y distance, and that's all there is to it. No more kinetic energy can be 'created' from that 120 calories worth, than that locked in 120 calories. The first law of thermodynamics underpins the entire fundamentals of the situation, and if for some reason anyone or any thing is capable of breaking this law, they will be world famous in an instant. (And probably dissected for science but that's a separate issue.)

How your personal body uses is has been governed again by physics and also by chemistry for the last 200,000 years, and the ones that could not be efficient with their energy use bought the farm and did not procreate. So that's 200,000 years of weeding out people who could not use calories very well.

I rather suspect that those of us who are left are pretty good at it, and what's more, pretty similar. We've been interbreeding for 200,000 years. Our genetics are 99.9% the same as each others.

In the big view, we're just not different enough for there to be any reasonable likelihood (other than genetic disorders and things like diabetes) that one person would have a special way of using calories.

Dalton1720

Regardless of metabolism, a pound of fat is ~3500 calories. Eating 500 calories below your daily usage will burn one pound a week... you just need to find what your daily usage is.

By daily usage do you mean your BMR? Because that seems awfully low.

lacroyx

1. How do we know the number we find on this site/any other site is accurate? say does a 120 gram banana really have 125 calories?

I like to cross check with this site http://ndb.nal.usda.gov/ndb/search/list
when I am not sure about the calories that a MFP entry has. I usually go with the closest and if I am not feeling lazy, create my own.

mactaffy84

If you have done any physics in high school, you might remember the first law of thermodynamics: that energy is neither created nor lost, but can only be transferred, transformed... transmuted. It can neither increase in size nor shrink in size. what were the kinds of energy? heat energy, kinetic energy, potential kinetic energy, gravitational energy, stuff like

In a closed system only. Humans are not a closed system! Why do we always forget this? It is hugely important when figuring out the kinetics of weight loss.