does food realy make you fat

Regardless of what you think about cals in vs cals out... I think the 1 thing people should take away from this thread is to quit paying so much attention to other people and get your own sht in order.

no, not necessarily.

"Why are thin people not fat":
http://inhumanexperiment.blogspot.co.uk/2010/07/why-are-thin-people-not-fat.html

"Does dieting make you fat?" (Twin study):
http://www.nature.com/ijo/journal/v36/n3/full/ijo2011160a.html

There is also a very interesting study giving evidence for the pretty much complete lack of correlation between someone's weight and calories consumed, but I can't seem to find it right now...

no, not necessarily.

"Why are thin people not fat":
http://inhumanexperiment.blogspot.co.uk/2010/07/why-are-thin-people-not-fat.html

"Does dieting make you fat?" (Twin study):
http://www.nature.com/ijo/journal/v36/n3/full/ijo2011160a.html

There is also a very interesting study giving evidence for the pretty much complete lack of correlation between someone's weight and calories consumed, but I can't seem to find it right now...

Ok first one is really interersting. I like it good read.

The second one looks insane. Is it really pointing out that people who have attempted to lose weight are more likely to become overweight? ...duh. And then they claim that means that calorie restriction causes weight gain long term...isn't that like saying that because diabetics avoid sugar that avoiding sugar causes diabetes?

Why do you all have to make it "skinny people eat less than they say"? I don't. Can you not accept the fact that there are naturally thin people?

No one said all skinny people eat less than they say.

What we are saying is that skinny people who try to claim they eat tons of food and therefore the calorie model is wrong eat less they say.

Thermodynamics, people: it's the law.

First off, it's LAWS. There's more than one. If you are referring to the first, when applied to humans -

The first Law of Thermodynamics in real life

A doctor leading a weight loss group responded to a question posed by her group as to why they were unable to lose weight. She said it was all because of the Law Of Conservation of Mass, also known as the Law of Thermodynamics. “This law of physics,” Dr. Val Jones wrote, “states that matter cannot be created or destroyed, although it may be rearranged.” That means that to lose weight, someone else has to gain it, since fat cannot be destroyed only rearranged. So, give your fat to someone else, she said. To that end, she’s been baking cookies. :-)

Of course, that was all in fun and the law of thermodynamics doesn’t really work that way. But Dr. Val was right about one thing: A lot of students probably slept during their pre-med physics class and don’t remember their professor’s lecture on the Law of Thermodynamics. That is evident, just as she quoted, by the fact that the most important part of the Law of Thermodynamics is usually left off.

Did you catch it?

As is often the case when science is dummied down into soundbytes, it becomes wrong. Such is the case in the distortion of the Law of Thermodynamics which has been simplified into the popular wisdom: “Calories in = calories out.” This simplistic adage has become something “everyone knows” to be true. It’s behind widely held beliefs that managing our weight is simply a matter of balancing calories eaten and exercise. While that’s been used to sell a lot of calorie-reduced diets and calorie-burning exercise programs for weight loss; sadly, it’s also been used to support beliefs that fat people “most certainly must be lying” about their diets and activity levels, because otherwise their failure to lose weight would seem to “defy the Law of Thermodynamics.”

While it might seem inconceivable, this simplified maxim is little more than superstition and urban legend. To realize this fact requires us to first go back to physics class and fill in the missing parts of the first Law of Thermodynamics.

The first Law of Thermodynamics, or energy balance, basically states that in a closed system, energy can neither be created nor destroyed, only transformed or transferred.

The human body is not a machine. There are countless, wildly varying, variables (external and internal) involved and that affect the efficiencies of a system and for which we have no control over. Understanding this helps to explain why calories cannot be balanced like a checkbook, and why people never seem to gain or lose precisely as calculated.

Balance in an open system, like the human body, is when all energy going into the system equals all energy leaving the system plus the storage of energy within the system. But energy in any thermodynamic system includes kinetic energy, potential energy, internal energy, and flow energy, as well as heat and work processes.

In other words, in real life, balancing energy includes a lot more than just the calories we eat and the calories we burn according to those exercise charts. The energy parts of the equation include: calories consumed; calories converted to energy and used in involuntary movement; calories used for heat generation and in response to external environmental exposures and temperatures; calories used with inflammatory and infectious processes; calories used in growth, tissue restoration and numerous metabolic processes; calories used in voluntary movement; calories not absorbed in the digestive tract and matter expelled; calories stored as fat, and fat converted in the liver to glucose; and more. Add to that, to put it simply, each variable affects the others, varies with mass and age, involves complex hormonal and enzyme regulatory influences, and differs in efficiency.

Calories eaten and calories used in voluntary movement are only two small parts of energy balance and are meaningless by themselves, unless all of the other variables are controlled for, as our metabolism… which they can never be as they aren’t under our control.


Engineering

These principles are well recognized by engineers and scientists who design thermodynamic systems. To better understand the Laws of Thermodynamics, as healthcare professionals we can learn a lot from engineers. Here’s an especially good explanation from Engineers Edge. [The entire book is available online here.] When balancing all of the energies-in to all of the energies-out plus energies stored within a system, engineers begin by considering:

If all of these energies interact within the system, then it’s an isolated system. But, of course, the human body is not an isolated system, exactly. It’s exposed to countless external influences and stresses. [Such as infections or external temperatures which can affect metabolism.]


There’s also a second Law of Thermodynamics, by the way, which explains the efficiencies of a closed system. This law dates back to the mid-1800s and basically says that it’s impossible to create a system that has perfect efficiency of energy conversion, as there are always some losses in the conversion process. The maximum possible efficiency is different than the observed efficiency. Over time, entropy increases and a system becomes more disordered and less efficient. Early in the developing science of thermodynamics, explains Engineers Edge, researchers realized that while work could be converted completely into heat, the converse is never true for a cyclic process. “Certain natural processes were also observed always to proceed in a certain direction” (such as heat always moves from hot to cold). A machine that converts heat from a warm body into work, without losing heat to a cooler body, would violate the second law of thermodynamics. The second Law of Thermodynamics is why physicists know that a perpetual motion machine is impossible (and not so simple, either).


Biology - Back to our bodies

The human body is a remarkable and incredibly complex and sophisticated system that normally keeps all sorts of things in balance, such as our fluid and electrolyte levels, our body temperature… and, yes, even our fat stores. When fat levels deviate from each body’s natural range, compensatory mechanisms kick in over weeks to return the body to its individual normal state, all without us having to think about it or having much to say about it. Even when eating a range of calories, our body weights stay within a surprisingly narrow range. The Law of Thermodynamics is more complicated than just calories eaten and burned in exercise, but it works in the body just like any other system.

“Body weight is remarkably stable in humans,” explained Dr. Jeffrey M. Friedman, M.D., Ph.D., head of the Laboratory of Molecular Genetics at Rockefeller University in New York. “The average human consumes one million or more calories per year, yet weight changes very little in most people. These facts lead to the conclusion that energy balance is regulated with a precision of greater than 99.5%, which far exceeds what can be consciously monitored.” In fact, error ranges in food calorie labels, assessed by calorimetry, are typically greater than 10%!

Scientists at Rockefeller University have conducted some of the most detailed, complex and precise metabolic research on energy balance and the biochemistry of fat, and shown in their renowned studies that fat people are metabolically no different from lean people, except they’re bigger. When within the weight range genetically normal for them, a fat person’s energy (caloric) balance per unit of lean body mass is indistinguishable from that of a ‘normal’ weight person. Fat people eat and burn calories no differently than naturally thinner people.

“A four hundred pounder who is maintaining his weight at his set point is no more a glutton than a hundred-fifty pounder at his set point,” wrote Robert Pool of his interviews with the Rockefeller researchers. Each body is eating and burning calories in energy balance.

Naturally fat and thin people are also alike in another way: It’s just as difficult for us to consciously vary our weights significantly — be it to lose OR gain — from what’s natural for our individual bodies and to maintain it for any length of time. Our bodies’ regulatory mechanisms work hard to preserve our bodies in their normal states — and biology nearly always wins. Research has shown that through willpower, diet and exercise, people have a long-term control over their weights within a 10- or 15-pound range, said Dr. Friedman. That's not going to ever change someone into a different body type -- make a naturally fat person thin or a genetically lean person obese.