Saturated fats provided the longest sensation of satiety, followed by protein, then high fibre carbohydrates.
Additionally, our livers have the nifty ability to create sure from pyruvate, lactate, glycerol, and glucogenic amino acids through a process called Gluconeogenesis.[2] Loosely, this is handy for the brain which usually uses glucose for energy, except during fasting when ketones are used.
1. https://en.wikipedia.org/wiki/Glycemic_index 2. https://en.wikipedia.org/wiki/Gluconeogenesis
Not sure about this. Will depend on the type of (over) eater. Do they over eat because of psychology (stress reaction), do they over-eat due to some hormonal imbalance (lower gut hormone despite eating) and subject keeps eating. Then there's binge eaters. Each of these three types of over-eating have a different "neurochemical hunger/stress response" to a normal person who has eaten enough and stops. [0]
[0] BBC Food, Gabriel Weston MDBS, Truth about Fat ~ https://www.youtube.com/watch?v=e9dDlKI623E
Carrying around extra fat causes N to go up.
"Getting fat people to go on diets that cause them to lose weight" is approximately as difficult, motivation-wise, as "Getting skinny people to go on diets that cause them to lose weight". It's extraordinarily difficult, because their bodies are screaming at them to go back to the refrigerator.
The novel question to answer is why overeating - consuming more calories than you burn, and thus gaining weight steadily over long time periods - is so much more prevalent now than it was in previous decades. Why people who are already fat are inclined to eat more (much more) than skinny people, is the simply metabolic reality of the body's drive for homeostasis.
There is a healthcare problem, of course, with having fat people around, but the scientific question of what is making them all have weight problems at higher rates than before, is somewhat distinct from the practical problem of how we get the existing fat demographic to lose weight. Aggressive funding of bariatric surgery seems to be the least-bad method of the latter for the moment; Almost nothing else can be shown to work effectively at the levels required, since we're effectively fighting the strongest drive the body has after breathing.
"The novel question to answer is why overeating - consuming more calories than you burn, and thus gaining weight steadily over long time periods - is so much more prevalent now than it was in previous decades."
Environment: more food, less exercise and incidental exercise. There is one intriguing idea, our bio flora (microbiota) is evolving and it's effecting us. ~ http://www.scientificamerican.com/article/how-gut-bacteria-h...
If a beverage has a certain number of calories from sugar per volume, it doesn't really matter whether it's cola-flavored, orange-flavored, vanilla-flavored, tea-flavored, natural-flavored, artificially-flavored, carbonated, uncarbonated, caffeinated, or uncaffeinated. They're all functionally soft drinks, from a dietary perspective, but the graph that charts the decline in carbonated soda does not show the other members in this group.
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B)
I actually harbor a hypothesis that I have not seen explored which would explain this even if we take it on face value. Contrary to traditional sources of sugar and starch, sweet beverages cause an absorption of sugar unimpeded by the normal vagaries of digestion - there's no chewing, nothing to slow a person down, no cell walls to slowly break down in the stomach, no fiber to absorb and slowly squeeze out the calories.
In the 90's, I used to drink two or three liters of birch beer for something to do while waiting for the pizza. You can keep pouring orange soda into a human body without complaint, long after they would have vomitted up a sugar-equivalent cherry pie. And often our behavior shifts to adopting soda whenever we look for a drink, as the default, several times a day.
We know that blood sugar spikes cause insulin spikes, and we know that ghrelin, insulin, & related hormones act together to modulate the hunger & satiety responses.
My hypothesis is that rapid sugar intake via drinks, when combined with our natural impulse to slake our thirst, acts to dysregulate our hunger and satiety responses in the longer term. Through whatever processes, it detaches hunger from ad libitum consumption levels, sufficient that an extra few hundred calories per day is the 'natural' level that affected people, on average, feel they should be eating. 100 extra calories a day over burn rate is about 10lbs/year of gained weight.
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C) Obesity is a lagging indicator here. People faced with an ad libitum diet find it very, very easy to maintain their weight. There seems to be a nearly universal misconception that baseline gluttony is associated with high weight levels, but that's bullshit. A person weighing 300lbs has roughly the same neurochemical hunger/stress response as a person weighing 150lbs, when you shortchange them each by 500 calories a day relative to their metabolic burn rate: It's just that metabolic burn rate goes way up as one gains weight. Maintaining weight is the default state. The mystery is why people are on average slowly gaining weight, rather than why fat people are not losing weight.