Fundamentals of Human Nutrition/Dietary intake Carbs< Fundamentals of Human Nutrition
4.5 Dietary Intake CarbohydratesEdit
This is personal, but exist reference what correct in any country for example: Dietary reference values for the intake of nutrients by Americans and Canadians - Adults should get 45 percent to 65 percent of their calories from carbohydrates.
- Type 2 Diabetes
4.5.2 Low-carbohydrate dietsEdit
A DASH diet recommends a diet that is 50-65% carbohydrate, 15% protein, and 20-35% fat. Low carbohydrate diets range between 5-30% carbohydrate. As protein intake tends to be fixed at 10-20%, carbohydrates and fat must be traded in order to ensure adequate caloric intake.
There are many different types of low carbohydrate diets. By restricting carbohydrates to roughly less than 150 grams/day, glucose, and thus insulin is decreased. High levels of insulin, especially in those that are insulin resistant, increase the level of fat storage. When insulin levels are low, either long after a high carbohydrate meal or nearly all the time if someone is on a low carbohydrate diet, free fatty acids accumulate in the blood stream. This increases energy availability and decreases hunger sensations as cells have a steady supply of energy.
When very low carbohydrate diets (less than 50 grams/day), an alternative metabolic state is entered. Free fatty acid release is significantly up-regulated and a metabolic state known as ketosis is entered. Ketones may be measured using "ketostix", which are available at drug stores.
Effectiveness of Carbohydrate DietsEdit
Cause of Heart DiseaseEdit
There are two models of heart disease, the Lipid Hypothesis and the Carbohydrate Hypothesis.
The Lipid Hypothesis states that a diet high in saturated fat will raise blood cholesterol, which will increase the risk for plaque formation and thus heart disease. Fat also has 9 calories/gram, while protein and carbohydrates have 4 calories/gram, and alcohol has 7 calories/gram. The well accepted nutritional advice states that fat makes you fat because it has more calories/gram. This was proposed by Ancel Keyes in the early 1960s, and after the 1972 conference governed by United States Senator George McGovern, lowering fat intake became the standard recommendation. People such as Dr. Robert Atkins fought the recommendations, but ultimately did not convince the committee.
The Carbohydrate Hypothesis is an alternative, largely untested, hypothesis for what makes people fat and what causes heart disease. High carbohydrate diets, especially those high in refined carbohydrates like white bread, white rice, pasta, and sugar raise blood glucose levels very quickly. Glucose, which can react with small, dense LDL, must be put into the cells. The pancreas releases large amounts of insulin, which stores the glucose in the fat cells in the form of fat. In between meals, fat is released and provides the individual with energy.
Chronically high insulin levels will cause muscle cells to become insulin resistant. The muscle cells down-regulate insulin receptor activity and thus the glucose stays in the blood where it can cause problems. The pancreas must produce more insulin in order to store the glucose, which increases the risk of fat cells becoming insulin resistant. When the fat cells are insulin resistant and there is free floating insulin in the blood stream, free fatty acids release is down-regulated. An individual then experiences hunger, as their alternative source of energy is no longer easily available. They then overeat, which increases their caloric intake leading to weight gain. If they do not overeat, their metabolism will be decreased in response to their decreased energy availability, despite eating an adequate number of calories. People do not get fat because they overeat, people overeat because they're getting fat. It's a starvation response and lowering caloric intake, which will promote weight loss, will also promote muscle loss.
Carbohydrates also increase the small, dense LDL particles and triglycerides, whereas saturated fat increases large, buoyant LDL and HDL. The small, dense LDL particles can get under the arterial cell walls, where the can oxidize and form a plaque. This plaque necessitates increased arterial pressure leading to high blood pressure and an enlarged heart to pump blood at an increased pressure. If the plaque is large enough and breaks, it may form a clot in the brain, heart, or other vital organ leading to strokes, heart attacks and other damage. If the plaque does not detach, but the heart continues to work hard, heart disease may occur.
In biology, ketosis is a state of the organism characterised by elevated levels of ketone bodies in the blood, by the processes of lipolysis and beta-oxidation. Ketone bodies are formed from excess amount of fat break down. Some of these ketone bodies such as acetoacetate and ß-hydroxybutyrate can also be used for energy. When glycogen stores are not available in the cells, fat (triacylglycerol) is cleaved to give 3 fatty acid chains and 1 glycerol molecule in a process called lipolysis. Most of the body is able to utilize fatty acids as an alternative source of energy in a process in which fatty acid chains are cleaved by coenzyme A (CoA) to form acetyl-CoA, which can then be fed into the Krebs cycle. Acetyl-CoA can only enter the Krebs cycle bound to oxaloacetate. When carbohydratesupplies are inadequate to maintain blood glucose levels, the liver naturally converts oxaloacetate in the liver to glucose via gluconeogenesis for use by the brain and other tissues. Excess acetyl-CoA in the liver is used to produce ketone bodies, leading to a state of ketosis. During this process, a high concentration of glucagon is present in the serum, which inactivates hexokinase and phosphofructokinase-1 (regulators of glycolysis) indirectly, causing most cells in the body to use fatty acids as their primary energy source. Condition usually caused by diabetes and accompanied by dehydration, hyperglycemia, ketonuria, and increased levels of glucagon. The high-glucagon, low-insulin serum levels signal the body to produce more glucose via gluconeogenesis and glycogenolysis, and ketone bodies via ketogenesis.
During times when you can't eat (like when you are sleeping, when no food is available, or just when you are busy) your body switches over to burning the fat stored from last week's mammoth binge, and creates molecules called ketones or ketone bodies. The ketones can be used by your cells in place of the missing sugars, thanks to the body's ability to switch metabolic pathways on the fly. In other words, since you've burned up all your stored glycogen, and you don't have any new food coming in, ketosis kicks in, and your body uses the fat that was stored from a previous meal to fuel itself.
Contrary to popular rhetoric, a ketogenic, low carbohydrate diet is NOT a high protein diet. It's a high fat diet, with a moderate protein and a very low carbohydrate intake. A typical ketogenic meal includes some sort of protein, a source of natural fats (butter, cream sauce, olive oil, or coconut oil) and green leafy vegetables, such as in the picture at right.
Ketosis vs Ketoacidosis
The difference between the two conditions is a matter of volume and flow rate :
Benign dietary ketosis is a biochemically regulated and controlled process which results in a mild release of fatty acids and ketone bodies. Ketoacidosis is a condition in which massive, way above normal quantities of ketones are produced in an unregulated, wildly out of control biochemical situation.
Critics of low carbohydrate diets express concerns about the long-term health consequences of ketosis. The idea behind ketosis producing diets (typically very low-calorie diet programs) is to force the body to lose weight by burning body fat. Supporters of low carbohydrate eating plans claim that low-carbohydrate-diet induced ketosis is safe. They point out that dietary ketosis should not be confused with ketoacidosis, which is a life-threatening condition associated with untreated Type 1 Diabetes, caused by a lack of insulin. They argue that ketoacidosis doesn't occur in normal healthy individuals because the presence of insulin keeps ketone production in check so that only a mild, beneficial ketosis is achieved.
Zero Carb DietEdit
Low-carbohydrate diets can lead to quick weight loss, which has made several of them very popular. At the same time, however, these diets usually call for followers to eat more meat, and that can lead to other health problems along the way.
- Weight loss: This diets to lose weight, since the body first burns glycogen, which comes from the consumption of carbohydrates, for energy. Without these carbohydrates in your body, you begin burning fat for energy, which leads to short-term weight loss.
- Appetite control: That's often exactly what happens with low carb, high fat diets - you tend to eat less automatically - so appetite control appears to be a legitimate benefit of low carb diets.
- Another potential benefit of carb restriction is better glycemic (blood sugar) control.
- This diet canattributed to higher thermic effect and a decrease in appetite.
Foods with higher fat values, such as many proteins, usually contain more cholesterol. A high-cholesterol diet increases your chance of contracting heart disease, cancer and diabetes. You could also deprive your body of vitamins and minerals found in many carbohydrates that remain essential to your overall health.
When the person do this type diet also he/she doesn't have micronutrient and macronutrients, take headache, nausea, weakness, dizziness ab other</ref>
This diet is based in the caveman diet, Stone Age diet and hunter-gatherer diet. The paleolithic diet (abbreviated paleo diet or paleodiet), also popularly referred to as the caveman diet, Stone Age diet and hunter-gatherer diet. The ancestors would have thrived on during the Paleolithic era, the time period from about 2.6 million years ago to the beginning of the agricultural revolution, about 10,000 years ago.
Just eaten beef, pork, lamb, poultry, and game meat, if you can get it), fish, seafood, fresh fruits, vegetables, seeds, nuts, and healthful oils (olive, coconut, avocado, macadamia, walnut and flaxseed). Dairy products, cereal grains, legumes, refined sugars and processed foods were not part of our ancestral menu.
Benefits: When diet do to reduce food intake and exercise, this is will weight loss and consequent increase the risk chronic diseases But, according with Pedro Carrera Bastos believes this:
- Cardiovascular disease (heart disease, stroke, high blood pressure, congestive heart failure, atherosclerosis)
- Type 2 diabetes
- Autoimmune diseases (multiple sclerosis, rheumatoid arthritis, Crohn’s disease, ulcerative colitis, etc.)
- Nearsightedness, macular degeneration, glaucoma
- Varicose veins, hemorrhoids, diverticulosis, gastric reflux.
- Unbalanced diet
- High saturated fat consumption
- Totally new eating habits