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You can convert protein to glucose, called something I can't spell,
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The process of converting amino acids (protein) or the glycerol portion of fats to glucose is called gluconeogenesis.
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There are least 4 distinct fuels which the body can use: glucose, protein, free fatty acids (FFA), and ketones. However when we look at the relationships between these four fuels, we see that only glucose and FFA (fat) need to be considered.
The difference in the proportion of each fuel used will depend on the metabolic state of the body (i.e. aerobic exercise, weight training, normal diet, ketogenic diet/fasting).
In general, tissues of the body will use a given fuel in proportion to its concentration in the bloodstream. So if a given fuel (i.e. glucose) increases in the bloodstream, the body will utilize that fuel in preference to others. By the same token, if the concentrations of a given fuel decrease in the bloodstream, the body will use less of that fuel. By decreasing carbohydrate availability, the ketogenic diet shifts the body to using fat as its primary fuel.
Glucose and protein use
When present in sufficient quantities, glucose is the preferred fuel for most tissues in the body. The major exception to this is the heart, which uses a mix of glucose, FFA and ketones.
The major source of glucose in the body is from dietary carbohydrate. However, other substances can be converted to glucose in the liver and kidney through a process called
gluconeogenesis. This includes certain amino acids, especially alanine and glutamine. With normal glucose availability, there is little gluconeogenesis from the body’s protein stores. This has led many to state that carbohydrate has a ‘protein sparing’ effect in that it prevents the breakdown of protein to make glucose. While it is true that a high carbohydrate intake can be protein sparing, it is often ignored that this same high carbohydrate also decreases the use of fat for fuel. Thus in addition to being ‘protein sparing’, carbohydrate is also ‘fat sparing’
If glucose requirements are high but glucose availability is low, as in the initial days of fasting, the body will break down its own protein stores to produce glucose. This is probably the origin of the concept that low carbohydrate diets are muscle wasting. An adequate protein intake during the first weeks of a ketogenic diet will prevent muscle loss by supplying the amino acids for gluconeogenesis that would otherwise come from body proteins.
By extension, under conditions of low glucose availability, if glucose requirements go down due to increases in alternative fuels such as FFA and ketones, the need for gluconeogenesis from protein will also decrease.
Since protein breakdown is intimately related to glucose requirements and availability, we can effectively consider these two fuels together. Arguably the major adaptation to the ketogenic diet is a decrease in glucose use by the body, which exerts a protein sparing effect.
Free Fatty Acids (FFA) and Ketones
Most tissues of the body can use FFA for fuel if it is available. This includes skeletal muscle, the heart, and most organs. However, there are other tissues such as the brain, red blood cells, the renal medulla, bone marrow and Type II muscle fibers which cannot use FFA and require glucose. The fact that the brain is incapable of using FFA for fuel has led to one of the biggest misconceptions about human physiology: that the brain can only use glucose for fuel. While it is true that the brain normally runs on glucose, the brain will readily use ketones for fuel if they are available.
Arguably the most important tissue in terms of ketone utilization is the brain which can derive up to 75% of its total energy requirements from ketones after adaptation. In all
likelihood, ketones exist primarily to provide a fat-derived fuel for the brain during periods when carbohydrates are unavailable.
As with glucose and FFA, the utilization of ketones is related to their availability. Under normal dietary conditions, ketone concentrations are so low that ketones provide a negligible amount of energy to the tissues of the body. If ketone concentrations increase, most tissues in the body will begin to derive some portion of their energy requirements from ketones. Some research also suggests that ketones are the preferred fuel of many tissues. One exception is the liver which does not use ketones for fuel, relying instead on FFA.
By the third day of ketosis, all of the non-protein fuel is derived from the oxidation of FFA and ketones. As ketosis develops, most tissues which can use ketones for fuel will stop using them to a significant degree by the third week. This decrease in ketone utilization occurs due to a down regulation of the enzymes responsible for ketone use and occurs in all tissues except the brain. After three weeks, most tissues will meet their energy requirements almost exclusively through the breakdown of FFA. This is thought to be an adaptation to ensure adequate ketone levels for the brain. Except in the case of Type I diabetes, ketones will only be present in the bloodstream under conditions where FFA use by the body has increased. For all practical purposes we can assume that a large increase in FFA use is accompanied by an increase in ketone utilization and these two fuels can be considered together.
Relationships between carbohydrates and fat
Excess dietary carbohydrates can be converted to fat in the liver through a process called de novo lipognesis (DNL). However short term studies show that DNL does not contribute significantly to fat gain in humans. As long as muscle and liver glycogen stores are not completely filled, the body is able to store or burn off excess dietary carbohydrates. Of course this process occurs at the expense of limiting fat burning, meaning that any dietary fat which is
ingested with a high carbohydrate intake is stored as fat. Under certain circumstances, excess dietary carbohydrate can go through DNL, and be stored in fat cells although the contribution to fat gain is thought to be minimal. Those
circumstances occur when muscle and liver glycogen levels are filled and there is an excess of carbohydrate being consumed.
The most likely scenario in which this would occur would be one in which an individual was inactive and consuming an excess of carbohydrates/calories in their diet. As well, the
combination of inactivity with a very high carbohydrate AND high fat diet is much worse in terms of fat gain. With chronically overfilled glycogen stores and a high carbohydrate intake, fat utilization is almost completely blocked and any dietary fat consumed is stored. This has led some authors to suggest an absolute minimization of dietary fat for weight loss. The premise is that, since incoming carbohydrate will block fat burning by the body, less fat must be eaten to avoid storage. The ketogenic diet approaches this problem from the opposite direction. By reducing carbohydrate intake to minimum levels, fat utilization by the body is maximized.
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http://www.allyourstrength.com/nutrition_1002Fuel.html
Fats from animal and vegetable sources provide a concentrated source of energy in the diet; they also provide the building blocks for cell membranes and a variety of hormones and hormonelike substances. Fats as part of a meal slow down absorption so that we can go longer without feeling hungry. In addition, they act as carriers for important fat-soluble vitamins A, D, E and K. Dietary fats are needed for the conversion of carotene to vitamin A, for mineral absorption and for a host of other processes.
Fats—or lipids—are a class of organic substances that are not soluble in water. In simple terms, fatty acids are chains of carbon atoms with hydrogen atoms filling the available bonds. Most fat in our bodies and in the food we eat is in the form of triglycerides, that is, three fatty-acid chains attached to a glycerol molecule. Elevated triglycerides in the blood have been positively linked to proneness to heart disease, but these triglycerides do not come directly from dietary fats; they are made in the liver from any excess sugars that have not been used for energy. The source of these excess sugars is any food containing carbohydrates, particularly refined sugar and white flour.
Saturated fatty acids constitute at least 50% of the cell membranes. They are what gives our cells necessary stiffness and integrity.
They play a vital role in the health of our bones. For calcium to be effectively incorporated into the skeletal structure, at least 50% of the dietary fats should be saturated.
They lower Lp(a), a substance in the blood that indicates proneness to heart disease.
They protect the liver from alcohol and other toxins, such as Tylenol.
They enhance the immune system.
They are needed for the proper utilization of essential fatty acids.
Elongated omega-3 fatty acids are better retained in the tissues when the diet is rich in saturated fats.
Saturated 18-carbon stearic acid and 16-carbon palmitic acid are the preferred foods for the heart, which is why the fat around the heart muscle is highly saturated. The heart draws on this reserve of fat in times of stress.
Short- and medium-chain saturated fatty acids have important antimicrobial properties. They protect us against harmful microorganisms in the digestive tract.
Our blood vessels can become damaged in a number of ways—through irritations caused by free radicals or viruses, or because they are structurally weak—and when this happens, the body's natural healing substance steps in to repair the damage. That substance is cholesterol. Cholesterol is a high-molecular-weight alcohol that is manufactured in the liver and in most human cells. Like saturated fats, the cholesterol we make and consume plays many vital roles:
Along with saturated fats, cholesterol in the cell membrane gives our cells necessary stiffness and stability. When the diet contains an excess of polyunsaturated fatty acids, these replace saturated fatty acids in the cell membrane, so that the cell walls actually become flabby. When this happens, cholesterol from the blood is "driven" into the tissues to give them structural integrity. This is why serum cholesterol levels may go down temporarily when we replace saturated fats with polyunsaturated oils in the diet.
Cholesterol acts as a precursor to vital corticosteroids, hormones that help us deal with stress and protect the body against heart disease and cancer; and to the sex hormones like androgen, testosterone, estrogen and progesterone.
Cholesterol is a precursor to vitamin D, a very important fat-soluble vitamin needed for healthy bones and nervous system, proper growth, mineral metabolism, muscle tone, insulin production, reproduction and immune system function.
The bile salts are made from cholesterol. Bile is vital for digestion and assimilation of fats in the diet.
Recent research shows that cholesterol acts as an antioxidant. This is the likely explanation for the fact that cholesterol levels go up with age. As an antioxidant, cholesterol protects us against free radical damage that leads to heart disease and cancer.
Cholesterol is needed for proper function of serotonin receptors in the brain. Serotonin is the body's natural "feel-good" chemical. Low cholesterol levels have been linked to aggressive and violent behavior, depression and suicidal tendencies.
Mother's milk is especially rich in cholesterol and contains a special enzyme that helps the baby utilize this nutrient. Babies and children need cholesterol-rich foods throughout their growing years to ensure proper development of the brain and nervous system.
Dietary cholesterol plays an important role in maintaining the health of the intestinal wall. This is why low-cholesterol vegetarian diets can lead to leaky gut syndrome and other intestinal disorders.
Cholesterol is not the cause of heart disease but rather a potent antioxidant weapon against free radicals in the blood, and a repair substance that helps heal arterial damage (although the arterial plaques themselves contain very little cholesterol.)
http://www.westonaprice.org/know_your_fats/skinny.html
Why FAT?
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