Calories in calories out what science says

Also - it's not necessarily the laws of thermodynamics, it's the law of conservation of energy. Energy is conserved. So, for any system (our body for example), The amount of energy we take in (by eating) is equal to the amount of energy we expend (through our TDEE) plus the amount of energy we store (as fat). Period.

And the unit of energy is the calorie.

The weight we gain and lose is not in the form of calories, it's in the form of molecules which have a measurable mass. The ones involved in gaining and losing fat are (typically) retained by the body (and thus we gain weight) because they contain usable calories, and are (typically) released from the body when they are broken down as the calories are utilized.

There is no law of thermodynamics that is directly related to the above retention/release of molecules by the body. The "calories" we talk about aren't even actual calories, they are just a metaphor for "calorie-containing molecules." However, the efficiency with which an individual keeps/utilizes/releases those molecules tends to be consistent enough over time (except when certain diseases intercede) so that the concept of calories in/out still is the only effective way to control one's weight.

All other methods which claim to ignore calories still do create a deficit to produce fat loss. They might mask it by preventing someone from eating all the foods they like, thus producing a low caloric intake, or other smoke-in-mirrors, but it's still ultimately the calorie surplus/deficit itself that produces fat gain/loss.

The problem with "a calorie is a calorie" is that it does not account for the synergistic effects of selecting the wrong type of calories.

There is no such thing as "right" or "wrong" calories. Calories are a unit of energy. There are foods that are nutrient dense or less nutrient dense or not very nutrient dense but that doesn't make them right or wrong. They can all be good or bad depending on context and dose. You are confusing calories with nutrients.

The "nutshell" confuses the conservation of energy with the conservation of mass. A closed system can lose or gain energy without changing mass. The only way to lose weight through a loss of energy is through an atomic reaction. Those are not happening in your body (unless you are very unlucky).

The main way that we lose weight is by breathing. We inhale O2 and we exhale CO2. That's a loss of excess carbon with every breath we take. We also lose weight by urinating and sweating. This has us lose H2O. Both CO2 and H2O are the results of the oxidation process that happens within our cells. And we happen to get rid of this waste with nearly perfect efficiency.

Thus, we burn O2 that we breath, and fuel in our body. This creates waste largely in the form of CO2 and water. We eliminate the waste. The burning process causes the waste, and that is what creates the link between burning calories and losing weight. But its not a direct link. And the loss of weight is a loss of mass, not energy.

DuffyPrat? Perfect username. Strong first post.

Here's a study for you all to dissect. Happy New Year!

http://www.ncbi.nlm.nih.gov/pubmed/22215165

Still CICO.

There were no significant differences between energy intake and energy expenditure between the 3 diets. We can account for all excess energy consumed through energy stored in fat and in protein or expended in higher total energy. With the low protein diet, more than 90% of the extra energy was stored as fat. Because there was no change in lean body mass, the 6.6% increase in total energy expenditure reflects the energy cost of storing fat and is close to the estimate of 4% to 8% for fat storage derived by Flatt.31 With the normal and high protein diets, only about 50% of the excess energy was stored as fat with most of the rest consumed (thermogenesis). The high total energy expenditure probably reflects the higher cost of protein turnover and storage.

(Taken from the full report.)

In classical physics, there was a law of the conservation of energy, and a law of the conservation of mass. Special relativity merged these two laws because in atomic reactions matter can turn into energy. Atomic reactions don't occur in the body.

In the body, there are physical (mechanical) changes, and there are also chemical reactions. In either of these, mass is conserved.

On the mechanical side, when you ingest food and when you inhale, you gain weight. When you excrete waste, sweat, and exhale, you lose weight. On the one hand, stuff that was outside of you is now inside of you. And then, stuff that was inside of you is outside of you.

At the chemical level, you don't lose weight. Instead, what you do is convert stuff that you put inside of you into stuff that becomes waste and then gets put out of you. One of the main ways that we do that is by burning glucose, which is the fuel that cells use in aerobic metabolism. Here is the simple glucose reaction:

6O2 + C6H12O6 ---> 6CO2 + 6H2O

The oxygen molecules get into the body by breathing. The glucose enters the body by eating (and then may go through some other conversions before being burned, because we rarely eat anything like pure glucose). During the reaction, all mass is preserved, so no weight loss occurs. The Carbon dioxide gets exhaled, and its heavier than the oxygen that was inhaled. The water gets retained or excreted through urination.

There are all sorts of ways to lose weight. A quick way, but one that most people seem not to prefer, is simply to cut off your legs. But we're not interested in losing weight, we are mostly interested in reducing stored fat. Lots of diets work to begin with because people lose water weight, and again thats not what we are interested in. Other diets work in a way that burn lean tissue along with excess fat, and we don't want that. Instead, we are looking for ways to make it so that the above reaction occurs and the source of the glucose in the reaction is largely our stored fat tissue.

And for what its worth, what I've said should probably be very troubling to the OP.