6) CONTROLLING WEIGHT
c) The Endless Cycles of an Overweight Person with Type 2 Diabetes
In type 2 diabetes excess weight and excess body fat around the middle acts in a circular fashion, feeding on itself to increase weight. The excess of body fat around the middle results in insulin resistance via mechanisms that are unclear at the current time. Insulin resistance results in elevated levels of circulating fat (triglycerides) in the blood stream. The liver reacts to the high levels of circulating fat by converting excessive amounts of it to cholesterol. The cholesterol is released to the intestines where it is absorbed into the bloodstream. The high levels of both cholesterol and triglycerides in the blood stream (hyperlipidemia) coat the inside of the blood vessels and can result in heart attacks and strokes. More fat builds up in the blood and more fat is stored around the middle. The weight goes up. And the cycle just gets more and more vicious.
There are other related cycles that are just as damaging. Most type 2 diabetes begins being overweight which in turn results in a resistance to insulin which in turn results in high glucose levels. If a person with type 2 diabetes is in the early stages of the disease and the underlying cause of their type 2 diabetes is insulin resistance and not the inability to produce insulin, then it is very possible that the person with diabetes actually has much more circulating insulin than a "normal" person. Reducing the amount of glucose in the blood is only one of the many functions of insulin. Insulin drives the liver to produce glycogen (body stores of carbohydrate) from glucose until the liver is saturated with glycogen. At that point insulin begins to drive the liver to produce triglyceride fats. And the insulin then drives the fat cells in the body to pick up and store the triglyceride fats. Furthermore, the excess insulin forces the muscle cells of the body to absorb glucose preferentially over triglyceride fats. So the body weight goes up and the cydle repeats itself.
Excess insulin reduces metabolism (actually catabolism), increases the level of triglyceride fat in the blood and increases the incorporation of triglyceride fat into adipose fat cells. Because the person with type 2 diabetes is insulin resistant, the glucose that would normally be shunted into the muscles via the high levels of insulin ends up going into fat. In other words, a person with type 2 diabetes who makes excess amounts of insulin is going to have less energy, gain weight, get fatter and have higher levels of damaging triglycerides in the blood stream. And the insulin resistance will increase as the weight increases.
Ultimately, as the beta cells in the pancreas die off, the amount of insulin produced will decrease to levels well below normal. It would be nice if everything would balance out at that point and the reduced insulin increased energy (basal metabolism or catabolism), decreased the level of triglycerides in the blood and decreased the incorporation of triglycerides into fat cells. But the glucose intolerance of the cells doesn't get any better, so glucose can't get into the cells, the individual will have even less energy, the individual will have to inject insulin, glucose will build up in the bloodstream, the liver will convert the glucose to triglycerides, the triglycerides will coat the blood vessels and build up in the fat cells, weight will increase, insulin resistance will increase and the cycle continues unabated.
It can all be summed up by saying that having diabetes causes fat to accumulate and fat accumulation causes diabetes. These "vicious circles" explain why people who are even slightly insulin resistant can have great difficulty losing weight and keeping the weight off, the greater the insulin resistance the greater the difficulty of losing weight. But they also explain why persons with type 2 diabetes must get down to absolutely minimum weights.
Current Chapter: 6) CONTROLLING WEIGHT
a) Introduction
b) What is "Overweight"
c) The Endless Cycles of an Overweight Person with Type 2 Diabetes
d) Food and Diet
e) Food "Rules"
f) USDA Food Pyramid
g) Adaptive Human Body
h) Timing of Meals
i) Serving Size
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