Dear Dr Rosensweet:
I am 53 and am 40 lbs. overweight. I have dieted many times. I have cut as much fat out of my diet as I possibly can, but still do not lose weight. Can you help? J.F., Naples

Dear J.F:
Weight loss is a complex topic with many factors related to it. It is rarely just a matter of calorie counting and fat intake. Today I will use the clues you have given me to discuss one of the common causes of unwanted weight gain: excessive carbohydrates. Because fat deposition is so obvious in excessive weight gain there is a generalized 'fear of fat'. Intake of excessive carbohydrates are more often at the root of the problem. Let me explain.

Pure food consists, as you probably know, of carbohydrates, proteins, fats, vitamins and minerals. Carbohydrates are comprised, in essence, of long chains of glucose molecules that break down to glucose by a healthy digestive process. Glucose is like rocket fuel: it burns 'hot' through a process called 'oxidation'. You may know that excessive oxidation can be harmful to the body and it is why you hear so much about "anti-oxidants". Glucose is so quick to "oxidize" that it is a far more dangerous molecule, if not carefully managed, than fat (which oxidizes slowly).

Our body strongly regulates the amount of glucose in the blood available at any moment. Our physiology aggressively prevents excesses of glucose by a significant protective mechanism that relies upon a hormone called insulin. Insulin reduces excessive glucose in the blood by causing the glucose to move out of the blood and into cells. Insulin also causes fats that are in the blood to move into cells.

The process of glucose regulation begins with digestion. As soon as glucose is absorbed out of the intestine and into the blood of the 'portal vein' (a blood vessel that goes from the intestine directly to the liver), sensors in the 'portal vein' detect its presence. During a meal that contains carbohydrate, the absorption of glucose will quickly raise the portal vein glucose content. The sensors then call for the release of insulin. Most of the glucose from the meal is immediately taken up by liver cells because excessive glucose levels in the blood are not safe.

There is no immediate metabolic need for all of the glucose that would be available from a meal that contains abundant carbohydrates. We wouldn't want excessive easy-to-oxidize glucose floating about with no purpose. Therefore, much of this glucose is processed in the liver. It is converted to storage forms, either as glycogen, (a re-usable form of carbohydrate), or as simple fats called 'triglycerides', (a fat that can be circulated and 'burned' as fuel, or stored). Again, fats are slower and 'quiet' in their oxidation and are thus safer to 'burn'.

The body stores reserves of fuel to be available for the times in the day when we are not eating or digesting. Glycogen is stored in the liver or the muscles, though not in great quantities. Fat is burned or stored, depending on needs generated by basic living and physical activity levels. It is the excessive storage of fat that sooner or later in our lives becomes our concern. Remember that fat can be derived from glucose, the base of all carbohydrates!

When you don't listen to the words of your mother and you skip your breakfast or other meals, you gradually use up enough blood glucose to decrease it below an acceptable level. This low blood glucose is not tolerable because many crucial body cells need energy. Mechanisms to restore normal glucose levels will come into play. Most, but not all, of our cells can burn either glucose or simple fats to produce energy. The simple fat, triglyceride, even though derived primarily from glucose, cannot be converted back to glucose. It is not possible for your body to pull glucose from stored fat. It can pull that fat back into service as fuel for many cells. It cannot convert it back to glucose. Because the brain, red blood cells and certain kidney cells can burn only glucose, when glycogen reserves are too low, the body resorts to another mechanism to supply glucose from within. A hormone is secreted that can actually stimulate the conversion of protein into glucose, in a process called "gluconeogenesis". The principle source of that protein is your muscles. Yikes! Under conditions of glucose need you will eventually break down your own muscles! You may have thought by skipping that meal you lose weight, but in reality, you often wind up losing muscle.

By the way, have you ever been hungry, not eaten, and noticed that the hunger disappeared? That sensation of hunger occurred because blood glucose levels had fallen too low. Your brain had detected this and gave you a strong signal to go out foraging for food. The hunger disappeared because when you did not eat your body accessed stored fuel from glycogen, fat, and muscles, as mentioned above. The hormones that are used to access stored fuel are adrenaline, cortisol, and glucagon. It is the cortisol that initiates gluconeogenesis.

Do adrenaline and cortisol sound familiar? They are the principal hormone first-responders in stress. Stress, of course, also has increased metabolic needs and supplying extra fuel is part of what these stress hormones generate. Excessive adrenaline and cortisol lead to a biological insulin resistance, which is harmful. In this phenomenon, insulin just does not work as well. Another cause of insulin resistance is the long term overstimulation of insulin from excessive intake of carbohydrates. As insulin resistance develops, glucose, triglyceride and cholesterol have more difficulty entering cells to be utilized as fuel, and the levels of these in the blood elevate.

You can surmise that one way to gain weight would be eat excessive carbohydrates. Many of the carbohydrates will coverted to fat and much of the fat will be stored. Also, if you eat excessive carbohydrates you will have to generate more insulin and, thus, raise its levels to higher than ideal. Eventually you will wear down your ability to produce adequate insulin.

Look at the possibilities: overeating carbohydrates, skipping meals, and stress all lead to elevated insulin, elevated cortisone and adrenaline, and insulin resistance. When you are no longer young but still eating as if you were, and become less physically active, the fat deposition begins. So you diet. And you reduce the fat content in your meals because you are afraid of fat. (That means you will emphasize carbohydrates by default). Also, you reduce your calories. But, your body needs glucose so your cortisol and adrenaline are secreted and you convert your muscles into glucose. Insulin levels rise. You, however, continue to eat carbohydrates. You store more fat!

This is an abbreviated version of a part of the complex picture relating to weight gain. For those interested in more details, I highly recommend the book, The Schwartzbein Principle by Diana Schwartzbein M.D.. High blood pressure, diabetes and hardening of the arteries are all related to this topic as well. You didn't ask about that, however, so I will save it for another time.

You can find more extensive information on this topic in the chapter on weight loss in my new book: Menopause and Natural Hormones- available at www.MenopauseandNaturalHormones.com

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This article is from www.RosensweetMD.com and is Copyright 2003 Daved Rosensweet M.D.