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What Makes Us Fat

By Dr. Moghissi - March 2010

Several years ago I wrote an article about weight loss discussing energy balance and “calories in” needing to be less than “calories out”. It turns out that was a very naïve and simplistic view, and very rarely works. I’ve been doing lots of research, and would like to share some very interesting information with you. It turns out, that limiting carbs really may be the answer to weight loss and good health. This will get a little technical, but bear with me, because understanding the physiology behind fat storage is extremely enlightening when trying to make lifestyle changes. BTW -what I’m about to explain actually comes out of basic medical textbooks, and in that sense is not controversial.

Basically, foods are either composed of fats, proteins, or carbohydrates (CHO) or a mixture of the three. When we eat food, the proteins are absorbed as proteins, fats as fatty acids (FA) and carbohydrates as various forms of glucose (sugar). All three can be used for fuel. Right now we are only interested in FA and CHO.

When we eat, CHO will be absorbed and cause a rise in glucose (blood sugar). Insulin is then produced by the pancreas to allow the glucose to be taken up by the cells as fuel. Glycerol is then produced as a byproduct. FA can also be used as fuel. BTW – the liver can and will also produce glucose and fatty acids when necessary.

In the fat cells, fat is stored as triglycerides (TG), which are comprised of one glycerol molecule + three FA molecules. Glycerol is produced when glucose is used as fuel. TG’s are too big to go through the cell walls so must be broken down into its individual pieces to go through the wall. The only way glycerol can get into the fat cell is with the help of insulin, and the only way it can get out is when the insulin level is very low.

Fat Diagram

So the fat in the fat cells are actually TG molecules that are assembled in the fat cell from glycerol and fatty acids that get stuck there because the TG molecule is too big to get back out. Actually, the TG molecule is constantly breaking up and reforming, but as long as there is a glycerol molecule inside the cell, it will suck in enough FA molecules to make sure it can be a TG. Remember, the only way that glycerol can get out is when the insulin level in the blood stream is very low.

So how do we decrease the storage of fat? We need to prevent TG from forming in the fat cells. Since the liver will produce fatty acids to pair with the glycerol, we need to prevent glycerol from getting into the fat cells. To do that, we need to lower the insulin level in the blood stream. What causes insulin secretion? The ingestion of carbohydrates. So how do we prevent from getting fat? Eat less carbs. That, by the way, is why the Atkins diet worked. People can eat as many calories as they want as long as they eat no carbs and not only will they not get fat, but they will lose fat like crazy because their insulin levels are low and the glycerol and FA’s come streaming out of the fat cells.

So you can see why right now all the major players in the weight loss industry are advocating low carb diets. This is only the tip of the iceberg, and there are lots more out there as to why it is so difficult to lose weight. If you have questions, I’d love to talk about your situation in person with you; feel free to come in for an appointment to discuss this further.

Please watch for additional articles with further information in the near future.

Jasmine Moghissi, M.D.

Focus - Health Tips » What Makes Us Fat

What Makes Us Fat

By Dr. Moghissi - March 2010

Several years ago I wrote an article about weight loss discussing energy balance and “calories in” needing to be less than “calories out”. It turns out that was a very naïve and simplistic view, and very rarely works. I’ve been doing lots of research, and would like to share some very interesting information with you. It turns out, that limiting carbs really may be the answer to weight loss and good health. This will get a little technical, but bear with me, because understanding the physiology behind fat storage is extremely enlightening when trying to make lifestyle changes. BTW -what I’m about to explain actually comes out of basic medical textbooks, and in that sense is not controversial.

Basically, foods are either composed of fats, proteins, or carbohydrates (CHO) or a mixture of the three. When we eat food, the proteins are absorbed as proteins, fats as fatty acids (FA) and carbohydrates as various forms of glucose (sugar). All three can be used for fuel. Right now we are only interested in FA and CHO.

When we eat, CHO will be absorbed and cause a rise in glucose (blood sugar). Insulin is then produced by the pancreas to allow the glucose to be taken up by the cells as fuel. Glycerol is then produced as a byproduct. FA can also be used as fuel. BTW – the liver can and will also produce glucose and fatty acids when necessary.

In the fat cells, fat is stored as triglycerides (TG), which are comprised of one glycerol molecule + three FA molecules. Glycerol is produced when glucose is used as fuel. TG’s are too big to go through the cell walls so must be broken down into its individual pieces to go through the wall. The only way glycerol can get into the fat cell is with the help of insulin, and the only way it can get out is when the insulin level is very low.

Fat Diagram

So the fat in the fat cells are actually TG molecules that are assembled in the fat cell from glycerol and fatty acids that get stuck there because the TG molecule is too big to get back out. Actually, the TG molecule is constantly breaking up and reforming, but as long as there is a glycerol molecule inside the cell, it will suck in enough FA molecules to make sure it can be a TG. Remember, the only way that glycerol can get out is when the insulin level in the blood stream is very low.

So how do we decrease the storage of fat? We need to prevent TG from forming in the fat cells. Since the liver will produce fatty acids to pair with the glycerol, we need to prevent glycerol from getting into the fat cells. To do that, we need to lower the insulin level in the blood stream. What causes insulin secretion? The ingestion of carbohydrates. So how do we prevent from getting fat? Eat less carbs. That, by the way, is why the Atkins diet worked. People can eat as many calories as they want as long as they eat no carbs and not only will they not get fat, but they will lose fat like crazy because their insulin levels are low and the glycerol and FA’s come streaming out of the fat cells.

So you can see why right now all the major players in the weight loss industry are advocating low carb diets. This is only the tip of the iceberg, and there are lots more out there as to why it is so difficult to lose weight. If you have questions, I’d love to talk about your situation in person with you; feel free to come in for an appointment to discuss this further.

Please watch for additional articles with further information in the near future.