Everyone believed this cargo cult "science" and it has had a devastating impact for hundreds of millions of people.
I want to believe the obesity problem is more of a portion control thing, for example, when McDonald's opened, did a normal adult actually eat a hamburger and small fries for lunch instead of a big mac and large fries? But once again, I always have trouble finding any real data to verify my hypothesis.
Junk food is also popular in Japan, though probably not as much as in the US. However, in general portions are smaller here in Japan and people don't drink soft drinks all day. Apparently the average American geek needs as much food as a Japanese construction worker.
http://www.guardian.co.uk/world/2006/mar/02/japan.justinmccu...
"About 24% of people aged 15 and over are considered overweight, compared with 65% in the United States."
Some of the conclusions from that article:
+ [H]ealth experts have warned that dietary changes, coupled with an increasingly sedentary lifestyle, are storing up trouble for Japanese children who, in their taste for burgers and instant noodles, have more in common with the average western teenager than with their tofu-loving grandparents.
+ "The Japanese used to eat food high in protein, but over the past few decades there has been a shift towards eating more animal fat, and that is at the root of the problem," said Shinobu Matsui.
+ [The Health Japan 21 program] has drawn up nutrition charts aimed at those most at risk of obesity - men, children and people living alone - encouraging them to eat more rice and vegetables and to cut down on meat.
They're not sedentary, and the portions are usually small.
You still see obesity in those cultures, particularly among the rich - and bingo! those groups are more sedentary and can afford to eat more.
I can tell you, the portions were significantly smaller in all cases.
For example: http://itc.conversationsnetwork.org/shows/detail4528.html
(Weight gain/loss is ultimately a simple equation: calories in ‒ calories out. Eat more but exercise more and they'll cancel out.)
Saying you're fat because you eat too much is like saying you're an alcoholic because you drink too much. It's true but it doesn't say anything about how to solve the problem and it mixes up cause and effect - in the former case you're eating more because you're getting fat (due to insulin resistance, caused by chronically high consumption of carbohydrates according to some or due to chronically high consumption of fructose according to others) and in the latter case you're drinking more because you're dependent upon alcohol.
I think you're really close to getting at the root of this problem right here. Fundamentally, we're talking about a behavioral compulsion here - people are literally getting addicted to food. Fructose is the substance that's hijacking the brain's reward system. A particular individual's susceptibility to obesity is very likely set up by the same factors that function in other addictions, whether chemical (as in alcoholism) or behavioral (as in gambling) - namely, dysfunctional family systems, psychological trauma, stress, etc. If this is, in fact, what's really going on then the solution is to (A) treat obesity as an addiction and (B) limit the proliferation of fructose in the food supply.
calories in - calories out = fat stored/burned.
So for calories in == calories out, stable weight. For calories in > calories out, weight gain. For calories in < calories out, weight loss.
The mistake that most people make is that they assume that the left side is independent of the right side. We can rewrite the equation as:
//Assume that a negative fat stored is fat burned calories in - fat stored - calories out = 0 OR calories in - fat stored = calories out
Now in your original equation, assume that the person needs 1000 calories for their body to function normally. Also assume that the person eats 1000 calories a day. In your equation, since you assume that fat storage is a function of imbalance between needs and consumption, you get 0 fat storage.
However, in reality because of an insulin imbalance, what happens is this: 1000 calories are consumed. 200 calories are stored as fat.
This only leaves 800 calories to be used by the body. But wait, the body requires 1000 calories to function normally! Well there's two ways to compensate for that, either the person will consumed an additional 200 calories to get the body functioning normally, or the body will adjust it's needs, reduce the energy and movement of the individual, sleep more, etc.
1. Your body is expecting a certain amount of calories at any point during the day which is either being pumped into your bloodstream from your fat or food in your gut.
2. Your fat doesn't work right, (probably because you eat too many carbs), and doesn't release enough calories, so you get hungry.
3. You keep over eating until you have enough volume of fat so that even though your fat doesn't work as well at releasing calories into your bloodstream, you make up for it by just having more.
4. Voila, you have reached homeostasis. Your body conspires to keep you at this weight. You are either hungry and thin or full and fat.
As for exercise, well, I can only offer up a personal anecdote. I lost 50 pounds. At first by starving myself with a calorie deficit and now I've figured out how to keep the weight off with the food I eat. (I no longer calorie count -- hooray).
During this period of weight loss I attempted to increase the amount I exercised to speed the process along. It didn't work. The only thing that moved the scale was either counting calories or eating a low carb diet, (paleo to be exact). If I had it to do over I'd just start with changing the things I eat, although because of years of calorie counting I'm now very aware of what I put in my mouth -- a good habit to have.
Edit: I do actually believe exercise can help you lose weight. I am currently training to race bikes. I go for very long rides (3-4 hours twice a week) to train my body to burn fat. This is critical for endurance sports. But I don't think it's realistic to ask everyone to become an endurance athlete.
I have weighed more, and i have weighed less. Not morbidly obese, but my doctor would prefer I dropped 20. I have found stress is a factor.
Carbs are supposedly "habit forming", they make you crave more carbs sooner.
Ultimately it's up to the individual to control how much they eat and exercise, but we've been misinformed for decades (and still, to this day!) on how to live healthily. The reason obesity has become an epidemic is surely due, at least in part, to this.
Literally.