[pvnick]

>I ended up shedding 30 pounds in 90 days, and have kept it off for a full year

>I probably upped my overall calorie consumption but I replaced the sugars with more complex energy sources like nuts

Unless you started exercising, these two statements are incompatible with one another (violates the first law of thermodynamics). What's more likely is you felt "fuller" from eating healthy foods and therefore consumed less calories.

[philwelch]

The laws of thermodynamics do not preclude your body from ingesting something that has calories and shitting it out without actually doing anything with the calories. Your shit would just have more calories left in it, kind of like how a poorly made car might leak gasoline everywhere.

[pvnick]

Your statement is only marginally correct, but mostly misleading to the point of being practically wrong. Depending on what you eat, your body absorbs 80%-97% of calories according to the following (simplified) equation:

Energy in = Energy out + Change in Body Stores [1]

Where "change in body stores" is, for all intents and purposes, either muscle or fat. So while going from eating 3000 calories of pure butter to eating 3000 calories of straight fibrous vegetables will show a modest difference in caloric retention, I guarantee you that's not the case here.

[1] http://www.bodyrecomposition.com/fat-loss/the-energy-balance...

[philwelch]

The point is, don't gloss over things by making dumb statements like "it's impossible because of the laws of thermodynamics". The laws of thermodynamics don't preclude engines that either leak fuel or are fantastically inefficient in converting them to any particular form whether it be locomotion, electricity, or adipose tissue. If your point is that the human body is fantastically efficient at producing fat in ways that don't really vary, then prove that point.

[pvnick]

Please don't insult me like that without at least reading the article I posted, which directly supports the statement "it's impossible because of the laws of thermodynamics"

[philwelch]

I'm not insulting you. The law of conservation of energy is insufficient to support your claim because your claim relies more on the particulars of human physiology than on the basic physics. If it were all down to physics, then my car would get fat when I put fuel in the gas tank and didn't drive it. But even though my car and my body are both governed by the same laws of physics, the details are different.

[iopq]

But your body doesn't do this so it's completely irrelevant. You can't fool your body into being less efficient by eating "healthier" which is the point of the parent.

[richcollins]

More likely increased BMR

[nitrogen]

It's possible that they are eating more calories, but digesting or storing fewer (thus passing more as waste).

[isleyaardvark]

Possible, but how likely is that? Is it more likely that he's eating foods that are inefficiently digested (and where are the scientific studies on that?) Or is it more likely that he's underestimating calories consumed (numerous studies showing many people doing just that)?

[donaldc]

Unless you started exercising, these two statements are incompatible with one another (violates the first law of thermodynamics). What's more likely is you felt "fuller" from eating healthy foods and therefore consumed less calories.

Another possibility is that the food eaten affects the metabolic rate. I've known multiple people who stopped having cold extremities when they cut back on their sugar intake.

[jaggederest]

Less than ten percent of your daily energy expenditure goes towards thermogenesis. That's not going to make enough of a different to lose 30 pounds in 90 days while taking in more calories.

You need a calorie deficit of approximately half a standard daily intake to lose a third of a pound a day.

[donaldc]

Not the full thirty pounds, but it could definitely be a contributing factor. And, if one's extremities get warmer while one's core temperature remains the same, the same amount of clothing is worn, and the ambient temperature remains the same, it's pretty much a certainty that more calories are being spent on heating the body.

[jaggederest]

You're talking about an extra 50 calories a day. It's going to be negligible against the 1100-1200 calorie deficit needed for that kind of weight loss. A half tablespoon of peanut butter.

Over the course of 90 days, you'd lose a grand total of a pound of fat or so.

[donaldc]

I think it could be more than that. Studies have found that some people have burned off an increase of hundreds of calories a day just through an increase in fidgeting.

And then there's this (http://www.medicinenet.com/script/main/art.asp?articlekey=99...)

Despite the fact that all of the subjects spent the same amount of time in exactly the same confined space, the results showed large differences in the number of calories they burned. Some subjects burned as few as 1,300 calories in 24 hours, while others burned as much as 3,600 calories, a difference of 2,300 calories in one 24-hour period!

Keep in mind that most of what these subjects were doing would not be counted as "exercise".

[jaggederest]

You were talking about thermogenesis, now you're talking about different activity levels. Not the same thing at all, really.

[iopq]

No, only calories really matter in terms of metabolic rate. Your metabolic rate increases in a surplus and decreases in a deficit.