Hunger and Satiety
Many people observe that when they eat foods high in protein and fat, they have a hard time binging. However, with carbohydrates, we don’t seem to have that protection. Many of us can imagine eating an entire container of movie popcorn with the butter, or finishing off a dozen donuts or even an entire pizza.
Researchers have studied the metabolic background of hunger and they made two important universal observations:
First, it’s possible to still be hungry on 10,000 calories of carbohydrates; and,
Second, that obese people tend to prefer carbohydrates more than lean individuals.
University of Vermont researcher Ethan Sims conducted overfeeding experiments on convicts. He found that a person can eat as much as 10,000 calories per day of mostly carbohydrates and still feel hunger late in the day. Subjects fed 800 superfluous calories of fat developed marked anorexia.
Sims and his colleagues neglected to publish the fact that it seemed impossible to fatten their subjects on high-fat, high-protein diets. Edward Horton, who was a colleague of Sims at the time, related that volunteers would sit staring at “plates of pork chops a mile high and they would refuse to eat enough of this meat to constitute the excess thousand calories a day that the Vermont investigators were asking of them. Elliot Danforth worked along with Sims and stated, “The bottom line is that you cannot gain weight on the Atkins diet. It’s just too hard. I challenge anyone to do an overfeeding study with just meat. You can’t do it. I think it’s a physical impossibility.”
On a more familiar level, one can imagine eating a large 20-ounce bag of movie popcorn (over 1100 calories) but not 1100 calories of cheese or even a cup and a half of melted Brie.
Both the anticipation of carbohydrates and the actual eating of them cause our bodies to secrete the hormone insulin which serves to deposit both fatty acids and glucose in fat tissue and it keeps those calories trapped in fat tissue once they get there. As long as we respond to carbohydrates by secreting more insulin, we continue to move nutrients from our bloodstream in expectation of the arrival of more, so we remain hungry or at least not fulfilled.
It’s not that fat fills us up; rather, it’s that carbohydrates prevent satiety. For the obese, these are profound complications. Whenever insulin is in circulation, fatty acids are not. Obesity results when fatty acids stay stored longer than they should.
We notice this at restaurants after we eat a large steak. We are particularly stuffed yet when the wait staff comes and offers a delectable treat, we seem to find room even though we know we’re stuffed. If the wait staff were to offer us more steak, we would likely refuse. This is the vicious cycle of hyperinsulinemia and this is present even in lean people.
The second observation is that obese people crave carbohydrates in two ways. In the first case, chronic insulinemia makes us hungry rather than insulin secretion
during a meal. In the second, we have the usual insulin responses in anticipation of and as a result of the meal. In both cases, insulin induces hunger or prevents satiety. In the case of hyperinsulinemia, this happens even between meals and/or during the night when the cells should be living off a fuel mixture predominantly of fatty acids. Instead, the high insulin traps the fatty acids in fat tissue and primes the cells to take up glucose in place of oxygen. As far as the body is concerned, this elevated insulin indicates that we’ve just eaten. However, in this case, we haven’t.
Our homeostatic system is expecting to deal with glucose but there is none coming in the diet. However, we’ve still hyper-secreting insulin. The liver will not give up its glycogen because of the high insulin in circulation and our blood sugar drops causing us to crave glucose. Even if we eat fat and protein, the hyperinsulinemia will serve to store those nutrients rather than allow them to be used for fuel.
The implication is critical to how we perceive the dietary treatment of obesity and one in which the current low-carbohydrate diet plans do not address.
The craving for carbohydrates is a physiological one heralded by high insulin. Any diet that fails to control both cravings and hunger is sure to fail. The craving for carbohydrates is more closely akin to an addiction as British clinician Robert Kemp described it in 1963. Carbohydrates cause Hyperinsulinemia through the diet creating an addiction similar to nicotine or cocaine or any other addictive substance. There is nothing inherently natural about these addictions. Te hunger that goes along with semi-starvation is an unavoidable condition. The craving for carbohydrates is not.
Sugar provides an exaggerated response to the region of the brain known as the reward center, the nucleus accumbens. Intense cravings for sugar may be explained by the intensity of the dopamine secretion in the brain when sugar is consumed. When the nucleas accubens is excessively activated by sweets or powerful drugs, it leads to abuse or addiction. When the system is underactive, it results in signs of depression. The fact that this is an addiction indicates that it can be overcome with sufficient time, effort, and motivation and this is not the case with hunger itself (except in the case of the anorexic).
Avoiding carbohydrates will lower insulin over time and so ameliorate the hyperinsulinemia that causes the carbohydrate craving itself. Dr. James Sidbury found that after a year to 18 months the appetite is normalized and the craving for sweets is lost.
Carbohydrate restriction is very difficult but with sufficient time and motivation, a person can indeed overcome their addiction to the sweet and thus improve their health.
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on November 12, 2008 at 10:19 am
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(Sigh!) So it will be 12 – 18 months before my hyperinsulinemia gets better? It’s a long time to be patient and keep the faith. I’m working on it.
on November 12, 2008 at 10:23 am
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What else would you do? It’s kind of like a drug addict who is having trouble with rehab. Some of them go to prison for two years (drug free) and they come out and go back immediately to the drugs. Dr. Sidbury said a year to 18 months before the urge for the sweet is lost and maybe he’s right.